Milk fat globule epidermal growth factor 8 alleviates liver injury in severe acute pancreatitis by restoring autophagy flux and inhibiting ferroptosis in hepatocytes

BACKGROUND

Liver injury is common in severe acute pancreatitis (SAP). Excessive autophagy often leads to an imbalance of homeostasis in hepatocytes, which induces lipid peroxidation and mitochondrial iron deposition and ultimately leads to ferroptosis. Our previous study found that milk fat globule epidermal growth factor 8 (MFG-E8) alleviates acinar cell damage during SAP via binding to αvβ3/5 integrins. MFG-E8 also seems to mitigate pancreatic fibrosis via inhibiting chaperone-mediated autophagy.

AIM

To speculate whether MFG-E8 could also alleviate SAP induced liver injury by restoring the abnormal autophagy flux.

METHODS

SAP was induced in mice by 2 hly intraperitoneal injections of 4.0 g/kg L-arginine or 7 hly injections of 50 μg/kg cerulein plus lipopolysaccharide. mfge8-knockout mice were used to study the effect of MFG-E8 deficiency on SAP-induced liver injury. Cilengitide, a specific αvβ3/5 integrin inhibitor, was used to investigate the possible mechanism of MFG-E8.

RESULTS

The results showed that MFG-E8 deficiency aggravated SAP-induced liver injury in mice, enhanced autophagy flux in hepatocyte, and worsened the degree of ferroptosis. Exogenous MFG-E8 reduced SAP-induced liver injury in a dose-dependent manner. Mechanistically, MFG-E8 mitigated excessive autophagy and inhibited ferroptosis in liver cells. Cilengitide abolished MFG-E8's beneficial effects in SAP-induced liver injury.

CONCLUSION

MFG-E8 acts as an endogenous protective mediator in SAP-induced liver injury. MFG-E8 alleviates the excessive autophagy and inhibits ferroptosis in hepatocytes by binding to integrin αVβ3/5.

[Population structure of food-borne Staphylococcus aureus in China]

Objective: To understand the population structure of food-borne Staphylococcus (S.) aureus in China. Methods: Whole genome sequencing was used to analyze 763 food-borne S. aureus strains from 16 provinces in China from 2006 to 2020. Multilocus sequence typing (MLST), staphylococcal protein A gene (spa) typing, and staphylococcal chromosome cassettemec (SCCmec) typing were conducted, and minimum spanning tree based on ST types (STs) was constructed by BioNumerics 7.5 software. Thirty-one S. aureus strains isolated from imported food products were also included in constructing the genome phylogenetic tree. Results: A total of 90 STs (20 novel types) and 160 spa types were detected in the 763 S. aureus isolates. The 72 STs (72/90, 80.0%) were related to 22 clone complexes. The predominant clone complexes were CC7, CC1, CC5, CC398, CC188, CC59, CC6, CC88, CC15, and CC25, accounting for 82.44% (629/763) of the total. The STs and spa types in the predominant clone complexes changed over the years. The methicillin-resistant S. aureus (MRSA) detection rate was 7.60%, and 7 SCCmec types were identified. The ST59-t437-Ⅳa (17.24%, 10/58), ST239-t030-Ⅲ (12.07%, 7/58), ST59-t437-Ⅴb (8.62%, 5/58), ST338-t437-Ⅴb (6.90%, 4/58) and ST338-t441-Ⅴb (6.90%, 4/58) were the main types in MRSA strains. The genome phylogenetic tree had two clades, and the strains with the same CC, ST, and spa types clustered together. All CC7 methicillin sensitive S. aureus strains were included in Clade1, while 21 clone complexes and all MRSA strains were in Clade2. The MRSA strains clustered according to the SCCmec and STs. The strains from imported food products in CC398, CC7, CC30, CC12, and CC188 had far distances from Chinese strains in the tree. Conclusions: In this study, the predominant clone complexes of food-borne strains were CC7, CC1, CC5, CC398, CC188, CC59, CC6, CC88, CC15, and CC25, which overlapped with the previously reported clone complexes of hospital and community-associated strains in China, suggesting that close attention needs to be paid to food, a vehicle of pathogen transmission in community and food poisoning.

[Safety of an inactivated 2019-nCoV vaccine (Vero) in adults aged 60 years and older]

Objective: To analyze the safety of an inactivated 2019-nCoV vaccine (Vero cell) in adults aged 60 years and older. Methods: A randomized, double-blind, placebo-controlled clinical study was conducted in May 2020 The eligible residents aged 60 and above were recruited in Renqiu city, Hebei Province. A total of 422 subjects (phase Ⅰ/Ⅱ:72/350) were enrolled. Two doses of the trial vaccine or placebo were randomly administered according to a 0 and 28-day immunization schedule. Subjects were randomly divided into two groups in Phase Ⅰ. Within each group, participants received vaccine or placebo in a ratio of 2∶1. Subjects were randomly divided into four groups in phase Ⅱ to receive low-dose, medium-dose, high-dose vaccine and placebo, respectively, in a ratio of 2∶2∶2∶1. A combination of regular follow-up and active reporting was used to observe adverse reactions within 28 days after vaccination, and compare the incidence rate of adverse reactions in the trial and control groups. Results: 422 subjects were (66.45±4.70) years old, and 48.82% were male (206/422). There were 100, 124, 124 and 74 patients enrolled into the low-dose, medium-dose, high-dose vaccine groups and the placebo group, respectively. One person without the vaccination was removed, and 421 participants who received at least one dose of vaccine were included in the safety analysis. Within 28 days after the first or second dose, a total of 20.67% (87/421) subjects had adverse reactions (both solicitation and non-solicitation). About 76 patients suffered grade 1 adverse reactions [18.05% (76/421)] and 22 patients suffered grade 2 adverse reactions [5.23% (22/421)]. No grade 3 or above adverse reactions occurred. A total of 19.71% (83/421) subjects had solicited adverse reactions. The most common grade 1 adverse reaction was injection site pain, followed by fever and fatigue. The most common grade 2 adverse reactions were fever and fatigue, followed by muscle pain and injection site redness. A total of 2.61% (11/421) subjects had unsolicited adverse reactions. A total of 1.66% (7/421) subjects had serious adverse events after vaccination, and no serious vaccine-related adverse events were reported. Conclusions: The inactivated SARS-CoV-2 vaccine is safe for people aged 60 years and above.

[Application of deep learning-based chest CT auxiliary diagnosis system in emergency trauma patients]

Objective: To investigate the diagnostic efficacy and potential application value of deep learning-based chest CT auxiliary diagnosis system in emergency trauma patients. Methods: A total of 403 patients, including 254 males and 149 females aged from 16 to 100 (50±19) years, who received emergency treatment for trauma and chest CT examination in the Eastern Theater General Hospital from September 2019 to November 2019 were retrospectively analyzed. Dr. Wise Lung Analyzer's chest CT auxiliary diagnosis system was applied to detect 5 types of injuries, including pneumothorax, pleural effusion/hemothorax, pulmonary contusion (shown as consolidation and ground glass opacity), rib fractures, and other fractures (including thoracic vertebrae, sternum, scapula and clavicle, etc.) and 6 other abnormalities (bullae, emphysema, pulmonary nodules, stripe, reticulation, pleural thickening). The diagnostic reference standards were labeled by two radiologists independently. The sensitivity and specificity of the auxiliary diagnosis system were evaluated. The imaging diagnostic reports were compared with the results of the auxiliary diagnosis system, and the diagnostic consistency between the two was calculated by using the Kappa test. Results: According to the reference standards, among the 403 patients, 29 were pneumothorax, 75 were pleural effusion/hemothorax, 131 were pulmonary contusion, 124 were rib fractures, and 63 were other fractures. The sensitivity and specificity of the auxiliary diagnosis system for detection of pneumothorax, pleural effusion/hemothorax, rib fractures, and other fractures were 96.6%, 97.6%, 80.0%, 99.7%, 99.2%, 83.9%, 84.1%, and 99.7%, respectively. The sensitivity of detecting lung contusion was 97.7%. There was a high consistency between the auxiliary diagnosis system and imaging diagnosis in the diagnosis of injuries, in which the kappa values of pneumothorax, pleural effusion, rib fracture and other fractures were 0.783, 0.821, 0.706 and 0.813, respectively (all P<0.001). Two cases of pneumothorax, three cases of pleural effusion/hemothorax, nine cases of rib fractures, and six cases of other fractures missed by imaging diagnosis were all detected by the auxiliary diagnosis system. The detection sensitivity of the auxiliary diagnosis system was higher for emphysema, pulmonary nodules and stripe (all>85%), but lower for bullae, reticulation and pleural thickening. Conclusions: The deep learning-based chest CT auxiliary diagnosis system could effectively assist chest CT to detect injuries in emergency trauma patients, which was expected to optimize the clinical workflow.

[The effect of booster dose vaccination 21- to 32-years after primary vaccination with hepatitis B vaccine in the population born from 1986 to 1996 in Zhengding County of Hebei Province]

Objective: Aanalysis the effect of booster one dose of hepatitis B vaccine after 21-32 years of primary immunization in Zhengding Country of Hebei Province. Methods: A total of 322 participants who were born between 1986 and 1996, received a full course of primary vaccination with plasma-derived hepatitis B vaccine (HepB), had no experience with booster vaccination, were HBsAg, anti-HBcnegative, had anti-HBs<10 mIU/ml, completed the booster and had laboratory results were enrolled between August 2017 to February 2018. A simple random method was uesd to randomly assigned 322 subjects to two groups, receiving a booster dose of HepB derived from either Saccharomyces cerevisiae ［HepB (SC), (151 cases)］ or Chinese hamster ovary-derived HepB ［HepB (CHO), (171 cases)］, the dose was 20 μg. Blood samples were collected 30 days after boosting and quantitatively tested for the geometric mean concentration (GMC) of anti-HBs to assess immunological effect. The related influencing factors of GMC and seroconversion rates of anti-HBs were analyzed by multiple linear regression and multivariate logistic regression models. Results: The 266 subjects (82.61%) had anti-HBs≥ 10 mIU/ml, and GMC was (131.63±12.94) mIU/ml.The seroconversion rates of anti-HBs in the anti-HBs<2.5 mIU/ml group and 2.5-10 mIU/ml group were 74.54% (161 cases) and 99.06% (105 cases), respectively (P<0.001).The seroconversion rates of anti-HBs after one dose of HepB (CHO) was higher than that of one dose of HepB (SC), the seroconversion rates were 87.13% (149 cases) and 77.48% (117 cases), respectively (P=0.023). Participants boostered with HepB (CHO) was the factor influencing the effect of strengthening immunization compared with boostered with HepB (SC), and OR (95%CI) was 1.91 (1.02-3.56) (P=0.042).Compared with anti-HBs<2.5 mIU/ml, prebooster anti-HBs was between 2.5 mIU/ml and 10 mIU/ml was the related factor of seroconversion rates of anti-HBs after booster immunization, and OR (95%CI) was 36.15 (4.91-266.02) (P<0.001). Conclusion: Participants boostered withone dose of HepB had a good immune response. Pre-booster anti-HBs concentration and a variety of vaccine were related factors of immune response.

Biological and ecological evidences suggest Stipa krylovii (Pooideae), contributes to optimal growth performance and population distribution of the grasshopper Oedaleus asiaticus

Oedaleus asiaticus Bey. Bienko is a significant grasshopper pest species occurring in north Asian grasslands. Outbreaks often result in significant loss in grasses and economic losses. Interestingly, we found this grasshopper was mainly restricted to Stipa-dominated grassland. We suspected this may be related to the dominant grasses species, Stipa krylovii Roshev, and hypothesized that S. krylovii contributes to optimal growth performance and population distribution of O. asiaticus. A 4 year investigation showed that O. asiaticus density was positively correlated to the above-ground biomass of S. krylovii and O. asiaticus growth performance variables (survival rate, size, growth rate) were significantly higher in Stipa-dominated grassland. A feeding trial also showed that O. asiaticus had a higher growth performance when feeding exclusively on S. krylovii. In addition, the choice, consumption and the efficiency of conversion of ingested food (ECI) by O. asiaticus was highest for S. krylovii compared with other plant species found in the Asian grasslands. These ecological and biological traits revealed why O. asiaticus is strongly associated with Stipa-dominated grasslands. We concluded that the existence of S. krylovii benefited the growth performance and explained the distribution of O. asiaticus. These results are useful for improved pest management strategies and developing guidelines for the monitoring of grasshopper population dynamics against the background of vegetation succession and changing plant communities in response to activities such as grazing, fire and climate change.

Clinical epidemiological survey of gallbladder carcinoma in northwestern China, 2009-2013: 2379 cases in 17 centers

Objective

To analyze the clinical epidemiological characteristics of patients with gallbladder carcinoma recruited from 17 hospitals in five northwestern provinces of China (Shaanxi Province, Gansu Province, Qinghai Province, Ningxia Hui Autonomous Region, and Xinjiang Uygur Autonomous Region) from 2009 to 2013, and to summarize the clinical diagnosis and treatment data of gallbladder carcinoma.

Methods

Clinical information of 2379 patients with gallbladder carcinoma from 17 hospitals in five northwestern provinces of China was retrospectively collected and analyzed using the “Questionnaire for Gallbladder Carcinoma Patients in Northwestern Area of China.” All information was verified with EpiData software and analyzed with SPSS 13.0 software.

Results

(1) Gallbladder carcinoma accounted for 2.7% (2379/86,609) of all biliary tract diseases during the study period, which was significantly higher than that from 1986 to 1998 (P < 0.001). (2) Gallbladder carcinoma was more prone to occur in elderly women. The male:female incidence ratio was 1.0:2.1, the average age of onset of disease was 63.7 ± 11.3 years, and the incidence was higher in farmers than in other occupational groups. (3) A total of 57.2% (1360/2379) of patients with gallbladder carcinoma also had gallstones. (4) Abdominal pain (1796/2379, 75.5%) and jaundice (727/2379, 30.6%) were the most common clinical manifestations, 81.2% (1527/1881) were positive in those receiving B ultrasound examinations and 90.7% (1567/1727) were positive in those undergoing computed tomography, and 64.5% (1124/1742) of patients with gallbladder carcinoma were positive for carbohydrate antigen (CA) 19-9. (5) The pathological type of gallbladder carcinoma was mainly moderately and poorly differentiated adenocarcinoma with a high degree of malignancy. At admission, 55.1% (1091/1981) of patients had stage IV cancer among patients with TNM staging information; 55.9% (1331/2379) had lymphatic metastasis, 29.7% (706/2379) had bile duct metastasis, and 53.1% (1263/2379) had liver metastasis. (6) A total of 283 patients (283/2379, 11.9%) had incidentally detected gallbladder carcinoma. (7) The rate of radical surgical resection was 30.4% (723/2379).

Conclusion

The proportion of gallbladder carcinoma in biliary tract diseases in the northwestern area of China was significantly higher from 2009 to 2013 than from 1986 to 1998. Gallbladder carcinoma was common in older women and mainly diagnosed at an advanced stage. Compared with other surveys in different regions, the rate of metastasis in this survey was high, leading to a low resection rate. Populations at high risk should undergo B-ultrasound examinations at regular follow-up intervals to increase the rate of early diagnosis of gallbladder carcinoma.

Tenascin-C promotes migration of hepatic stellate cells and production of type I collagen

Tenascin-C (TN-C) is an extracellular matrix glycoprotein markedly upregulated during liver fibrosis. The study is performed to explore the role of TN-C during the growth and activation of hepatic stellate cells (HSCs). We found that TN-C was accumulated accompanying with the HSC activation. Our data on cell migration assay revealed that the rTN-C treatment enhanced HSC migration in a dose- and time-dependent manner, but did not influence their proliferation. HSCs transfected with pTARGET-TN-C overexpression vector displayed increased the type I collagen (Col I) production. TN-C overexpression enhanced the process of HSC activation through TGF-β1 signaling. Moreover, the anti-α9β1 integrin antibody treatment blocked the TN-C-driven Col I increase in rat HSCs. Collectively, TN-C had a positive role in activation of HSCs mediated by TGF-β1 and α9β1 integrin, manifesting elevation of Col I production and promotion of cell migration. Our results provide a potential insight for the therapy of hepatic fibrosis.

[Progress of study on changes of mitochondrial and its role in obstructive sleep apnea hypopnea syndrome]

Obstructive sleep apnea hypopnea syndrome (OSAHS) is a common respiratory disease which has become an important public health problem. A high prevalence of OSAHS in the elderly may suggest that aging could be considered as a risk factor for the development of OSAHS. Recent work that has advanced understanding of mutations accumulating over time in the mitochondrial DNA (mtDNA) has been closely associated with aging. More and more researchers pay attention to changes of mitochondria morphology, electron transport chain enzymes and mtDNA. The process research of accumulation of circular mtDNA bearing deletions or mtDNA with accumulated point mutations in OSAHS subjects might be able to make mitochondrial become a representative biomarker for adverse outcomes from oxidative stress and cardiovascular diseases in the future.

Clinical effects of an improved preoperative bowel preparation method in colorectal cancer

AIM: To evaluate the clinical effects of an improved method of preoperative bowel preparation for colorectal cancer patients.

METHODS: Two hundred and ten colorectal cancer patients were randomly divided into three groups: A, B, and C (n = 80, 50, and 80, respectively). Groups A, B and C were given oral compound polyethylene glycol electrolyte powder (208.68 g) 18 h, 12 h and 12 h before operation, respectively. Group C was additionally given 40 mL glycerine enema into the anus 2 h preoperatively. All patients ate a liquid diet the night before operation and were forbidden from drinking water 4 h before operation. Then the patients underwent colonoscopy 1 h before operation. Intestinal cleanness and patient tolerance were compared among the three groups.

RESULTS: The rate of intestinal cleaning was significantly higher in group C than in groups A and B (P < 0.05). The tolerance was significantly better in groups B and C than in group A (P < 0.05).

CONCLUSION: Compound polyethylene glycol electrolyte powder combined with glycerine enema is a simple, safe, effective and rapid method for preoperative bowel preparation in colorectal cancer patients.

[Effects of alprostadil in prevention of portal vein thrombogenesis after splenectomy and devascularization: a clinical observation of 76 patients with portal hypertension]

OBJECTIVE

To investigate the effects of alprostadil (Lipo PGE1) in prevention of portal vein thrombogenesis (PVT) after splenectomy for portal hypertension.

METHODS

Seventy-six patients with portal hypertension undergoing splenectomy and pericardial devascularization were randomly divided into 2 groups :treatment group (n = 40), receiving intravenous drip of injection of radix Salviae miliorrhazae (RSM) 40 ml and alprostadil 20 microg, both once a day since the third day after operation for 2 weeks and then oral administration of dropping pill of SM, and control group (n = 36), receiving intravenous drip of injection of RSM and taking enteric coated aspirin 3 times a day for 2 weeks and then taking dropping pill of SM. Platelets (PLT), prothrombin time (PT), and liver function were detected periodically. Color Doppler ultrasonography was conducted every week to observe the blood flow velocity and diameter of the portal and splenic veins, and if PVT event and ascites occurred. All patients were followed up for 8 - 20 months.

RESULTS

No prolongation of coagulation time and bleeding tendency was found in both groups. The PLT number increased remarkably in the 7th to 14th days after operation without significant difference between the 2 groups (P >0.05). The PVT rate of the treatment group was 5.0%, significantly lower than that of the control group (25.0%, chi2 = 6.12, P < 0.05). The ascites rate of the treatment group was 10.0%, significantly lower than that of the control group (33.3%, chi2 = 7.44, P <0.01). The levels of ALT and total bilirubin 7 and 16 days after operation of the treatment group were all significantly lower than those of the control group (all P <0.05).

CONCLUSION

Use of alprostadil early after devascularization is an effective and safe measure to prevent PVT, improve liver function, and decrease ascites rate.

Activation of neurons in cardiovascular areas of cat brain stem affects spinal reflexes

In 65 cats anesthetized with chloralose (40 mg/kg) and urethane (400 mg/kg), the effects of electrical stimulation and microinjection of sodium glutamate (0.25 M, 100-200 nl) in the pressor areas in the rostral brain stem on the evoked L5 ventral root response (EVRR) due to intermittent stimulation of sciatic afferents were compared to stimulating the dorsomedial (DM) and ventrolateral (VLM) medulla. In general, stimulating these rostral brain stem pressor areas including the diencephalon (DIC) and rostral pons (RP) produced increases in systemic arterial pressure (SAP). In most of the cases (85%) there were associated changes in the EVRR, predominantly a decrease in EVRR (72%). Stimulation of the midbrain (MB, principally in the periaqueductal grey) produced decreases in SAP and EVRR. Decreases in EVRR was observed in 91% of the DM and VLM stimulations in which an increase in SAP was produced. This EVRR inhibition was essentially unaltered after acute midcollicular decerebration. Increases in EVRR were also observed and occurred more often in the rostral brain stem than in the medulla. Since changes of both EVRR and SAP could be reproduced by microinjection of Glu into the cardiovascular-reactive areas of the brain stem, this suggests that neuronal perikarya in these areas are responsible for both actions. On some occasions, Glu induced changes in EVRR but not in SAP. This effect occurred more frequently in the rostral brain stem than in the medulla. The present data suggest that separate neuron population exist in the brain stem for the integration of SAP and spinal reflexes.(ABSTRACT TRUNCATED AT 250 WORDS)

Increased plasma endothelin-1 concentration in patients with acute cerebral infarction and actions of endothelin-1 on pial arterioles of rat

In acute cerebral ischemia there are severe damages of endothelium which have been recognized as the stimuli to secrete endothelin-1, an endothelium-derived peptide and the most potent vasoconstrictor ever known. This study was to measure plasma endothelin-1 level in patients with cerebral infarction and explore the relationship between endothelin-1 and ischemic stroke. The possible involvement of endothelin-1 in local regulation of cerebral arterioles was also investigated. Plasma levels of endothelin-1 were measured by radioimmunoassay in 21 patients. Using a micro-video system, the endothelin-1 actions were also observed on rat pial arterioles in vivo, and with incomplete cerebral ischemia model (rat), effect of ischemia affects the endothelin-1 action. There was a marked increase in plasma endothelin-1 level in the patients and the elevation persisted during the acute and subacute period of stroke. There was a positive correlation between the peptide concentration and infarct size (r = 0.655, P < 0.01). In rats, endothelin-1 (dose range: 10(-10) mole/L-10(-7) mole/L) induced a dose-dependent arteriole contraction after subdural administration. Arteriole calibers were decreased by 27.7% +/- 3.8% (10(-9) mole/L), 46.8% +/- 4.9% (10(-8) mole/L) and 78.5% +/- 4.7% (10(-7) mole/L), respectively. Cerebral ischemia significantly enhanced the action of endothelin-1 (96.4% +/- 7.2% vs 58.2% +/- 6.8%). Endothelin-1 plays an important role in regulating local circulation of ischemic brain. The notable and lasting increase in plasma level of endothelin-1 are associated with cerebral ischemia and infarction.(ABSTRACT TRUNCATED AT 250 WORDS)

Evidence that rifampicin can stimulate readthrough of transcriptional terminators in Escherichia coli, including the attenuator of the rpoBC operon

The genes encoding the beta and beta' subunits of RNA polymerase in E.coli, rpoB and rpoC, lie downstream of at least two ribosomal protein genes, rplJ (encoding L10) and rplL (L7/12), in a common operon. All four genes are served by promoter PL10, and an attenuator (partial terminator) of transcription, t1, lies between rplJL and rpoBC. Treatment of E.coli with rifampicin, under conditions producing partial inhibition of general RNA synthesis, can stimulate transcription of rpoBC. We have investigated the locus of this effect by fusing PL10 and t1 separately to galK, in suitable plasmids. Our studies of these fusions, and similar fusions involving transcriptional terminators derived from coliphage T7, indicate that low concentrations of rifampicin cause increased readthrough of several different transcriptional terminators in E.coli in vivo, including rpo t1. We discuss whether or not this unspecific mechanism is solely responsible for the observed stimulatory effects of the drug on rpoBC transcription.

Internal promoters of the rpoBC operon of Escherichia coli

Four ribosomal protein genes, rplA, rplJ, rplK and rplL form an operon in E. coli together with the genes rpoB and rpoC which encode the beta and beta' subunits of RNA polymerase. Transcription is initiated principally at two promoters, PL11 and Pl, the overall structure of the operon being (in the direction of transcription) PL11 rplK rplA Pl rplJ rplL rpoB rpoC. Here we describe studies of phage lambda derivatives carrying various segments of this operon, which demonstrate the existence of at least three additional weak internal promoters, and help to define their positions and strengths.

The haemostatic effects of the Chinese herbal drug Yunnan Bai Yao: a pilot study

The effects of Yunnan Bai Yao on the bleeding time in rats and the blood clotting time in rabbits and man were studied. The medicinal preparation markedly shortened both the bleeding and clotting times; the decreases were significantly more intense than those inconsistently produced by starch or by starch with calcium. These preliminary findings suggest that the action of Yunnan Bai Yao appears not to be due to its pH (5.2) or to vasoconstriction, but other factors such as its calcium content or the physical effect of its particle size cannot yet be excluded.