[Radiological assessment of interstitial lung disease: what can lung ultrasound do?]

The use of lung ultrasound in the screening, diagnosis, and evaluation of interstitial lung disease has been relatively well studied, but has not been widely accepted and applied in clinical practice. There are also some differences in the examination methods applied in these studies. This paper summarized the application, advantages, and disadvantages of lung ultrasound in the diagnosis and follow-up of interstitial lung disease by comprehensively reviewing the examination methods, research results and progress of new technologies of lung ultrasound in interstitial lung disease.

Development and validation of a nomogram for predicting the risk of nursing home-acquired pneumonia

OBJECTIVE

Nursing home-acquired pneumonia (NHAP) is one of the most frequent infections in nursing homes, with a difficult diagnosis, poor prognosis, and high mortality. The present study was performed to develop and validate a nomogram to predict the risk of NHAP in nursing homes.

MATERIALS AND METHODS

Based on a literature review and clinician's recommendations, we identified and collected the possible factors affecting the occurrence of NHAP. Based on the above factors, a retrospective observational study of 620 nursing home residents' medical records was performed from September 2016 to September 2021. Significant risk factors for NHAP were identified by univariate and multivariate analysis successively. A nomogram was constructed based on the binary logistic regression models to visualize the prediction model. The model's performance was determined by the concordance index (C-index), and the prediction accuracy was evaluated using a calibration curve. Clinical effectiveness was evaluated by decision curve analysis (DCA).

RESULTS

Finally, 12 independent risk factors were identified and assembled into the nomogram. The nomogram had a C-index of 0.958 (95% confidence interval: 0.943-0.972). The area under the receiver operating characteristic curve (AUC-ROC) value of the nomogram was 0.958 (p<0.05), and the calibration plot showed good goodness of fit. The decision curve analysis and clinical impact curve showed good clinical usefulness of the nomogram.

CONCLUSIONS

A nomogram for the early prediction of NHAP, which is easy for nurses to perform in nursing homes, was successfully constructed and validated, and it had a good predictive performance.

Critical prognostic factors for poststroke dysphagia: a meta-analysis

OBJECTIVE

Poststroke dysphagia (PSD) is one of the most significant problems after stroke. The prognosis of dysphagia is closely related to the outcomes of stroke. This meta-analysis aimed at identifying and evaluating critical predictors of prognosis for PSD.

MATERIALS AND METHODS

Electronic databases were searched for relevant case-control and cohort studies in which the prognostic factors of PSD were reported. The methodological quality of the studies was assessed using the Newcastle-Ottawa Scale. Review Manager 5.3 was used to calculate odds ratios (OR) and their 95% confidence intervals (CI) of the included factors and to perform heterogeneity and sensitivity analyses. Stata 15.1 was used to evaluate publication bias.

RESULTS

Eighteen of 3132 total studies were finally included in this meta-analysis. Ten predictors of PSD were identified, including 2 protective factors and 8 risk factors. Early intervention (OR=0.75, 95% CI=0.61-0.93) and an MRS (modified Rankin scale) score of 0 before onset (OR=0.58, 95% CI=0.47-0.71) were related to a better prognosis of PSD. The risk factors ranked by pooled OR values were aspiration (OR=7.64, 95% CI=5.94-9.82), brainstem injury (OR=4.82, 95% CI=3.01-7.72), severity of stroke (OR= 3.06, 95% CI=1.69-5.53), bihemispheric injury (OR=3.0, 95% CI=1.67-5.40), older age (OR=1.75, 95% CI=1.50-2.04), malnutrition (OR=1.36, 95% CI=1.22-1.53), severe dysphagia on admission (OR=1.16, 95% CI=1.03-1.29), and reduced level of consciousness (OR=1.03, 95% CI=1.00-1.07).

CONCLUSIONS

Prognostic factors for a good outcome of PSD included early intervention and an MRS score of 0 before onset. Aspiration, brainstem injury, severe stroke and bihemispheric injury are the four most significant predictors of poor prognosis in PSD. Identifying these prognostic factors should help clinicians to better detect patients at risk and provide effective interventions for PSD.

[Prognosis and related risk factors of acute respiratory distress syndrome in elder patients]

Objective: To study the risk factors associated with the hospital survival rate of elder patients with acute respiratory distress syndrome (ARDS) in Medical/Respiratory Intensive Care Units (MICUs/RICUs) by evaluating the prognosis, and therefore to provide insight into patient treatment strategy. Methods: Twenty MICUs/RICUs of 19 general hospitals in mainland China participated in the multicenter prospective cohort study carried out from Mar 1^st, 2016 to Feb 28^th, 2018. Patients who met the criteria of Berlin ARDS and older than 65 years were recruited. Baseline data, risk factors of ARDS, ventilator setup and prognosis data were collected from all patients. Univariant and multivariant regression analysis were conducted to analyze the factors associated with the prognosis. Results: 170 elder ARDS patients (age≥65 years) met the Berlin ARDS criteria, among whom 8.8% (15/170), 42.9% (73/170) and 48.2% (82/170) patients had mild, moderate and severe ARDS, respectively. The most common predisposing factor for elder ARDS was pneumonia, which was present in 134 patients (78.8%). 37.6% (64/170) patients were treated with noninvasive mechanical ventilation (NIV), but 43.8% (28/64) cases experienced treatment failure. 76.5% (130/170) patients were treated with invasive mechanical ventilation. All patients 80 years or older were given invasive mechanical ventilation. 51.8% (88/170) cases had complications of non-pulmonary organ failure. 61.8% (105/170) patients deceased during hospital stay. Multivariant logistic analysis showed that the independent risk factors for hospital survival rate in elder patients with ARDS were SOFA score (P=0.030, RR=0.725, 95% CI 0.543-0.969), oxygen index after 24 hours of ARDS diagnosis (P=0.030, RR=0.196, 95% CI 0.045-0.853), accumulated fluid balance within 7 days after diagnosis of ARDS (P=0.026, RR=1.000, 95% CI 1.000-1.000) and shock (P=0.034, RR=0.140, 95% CI 0.023-0.863). Conclusion: Among 20 ICUs, the high mortality rate of elder patients with ARDS was correlated with higher 24 hour SOFA score, lower 24 hour oxygen index after ARDS diagnosis, more positive fluid balance within 7 days and concomitant shock. The conservative fluid strategy within 7 days of ARDS diagnosis may benefit the elder ARDS patients.

[The differentiation and vicissitude of variety of Aucklandiae Radix]

Aucklandiae Radix is a commonly used Chinese herbal medicine. Historically, the varieties of Aucklandiae Radix for its medicinal use are complicated. Early Radix Aucklandiae was produced domestically, and it began to be imported since the Northern and Southern Dynasties. The two families, four genera, including Saussure Aucklandiae Radix of Compositae, Inula Inulae Radix, Vladimiria Vladimiriae Radix, dali Aucklandiae Radix and Aristolochiaceae Aristolochic aristolochia debilis, are all applied for medicinal purposes. In modern time, there are 3 major classes of crude drugs of Aucklandiae Radix, namely, Aucklandiae Radix, Inulae Radix, root of common Vladimiriae Radix.

Flagellin-PAc Fusion Protein Inhibits Progression of Established Caries

Dental caries remains one of the most common infectious diseases of humankind, which develops slowly throughout life, affecting children, adolescents, and adults. A vaccine against caries is urgently needed. We previously developed recombinant flagellin as a mucosal adjuvant for anti-Streptococcus mutans vaccines by nasal immunization. Furthermore, we demonstrated a fusion protein strategy that combined flagellin and the target surface adhesion protein (PAc) in a single construct. This construct enhanced specific IgA responses in oral fluids and provided improved prophylactic protection against caries. In the present study, we observed prolonged progression of dental caries in rats after S. mutans Ingbritt challenge. In addition, we observed a therapeutic effect of the flagellin-PAc fusion protein (KF-rPAc) against dental caries as a mucosal vaccine with a new immunization protocol. The present study demonstrated that KF-rPAc by nasal immunization can promote PAc-specific systemic and mucosal antibody responses and inhibit dental caries progression efficiently after the implant of S. mutans into the oral cavity of the rats. The rats immunized with KF-rPAc exhibited 53.9% caries reduction compared with the sham-immunized rats. Our data support the concept of administration of KF-rPAc to humans after infection and even caries that has begun to alleviate caries progression. In conclusion, our study demonstrated that KF-rPAc could be used as an anticaries therapeutic mucosal vaccine.

Knockdown of MMP11 inhibits proliferation and invasion of gastric cancer cells

Matrix metalloproteinase 11 (MMP11 or stromelysin-3) has recently been reported to play a crucial role in the development and progression of multiple malignancies. The aim of this study was to investigate the function of MMP11 expression in human gastric adenocarcinoma (GAC). Using immunohistochemistry assay, we studied the expression level of MMP11 in GAC and adjacent non-cancerous tissues (ANCT). The association between MMP11 expression and tumor size and pathological grade, as well as metastatic potential was analyzed. Through small hairpin RNA (shRNA)-mediated MMP11 knockdown in SGC-7901 GAC cells, we observed the changes of the biological behaviors of GAC cells. Our results indicated that the rate of positive expression of MMP11 was higher in GAC tissues than in ANCT (55.0 vs 30.0 percent, P=0.025). MMP11 expression had no association with the factors of age or gender of the GAC patients, or the size, pathological staging and lymph node metastases of the tumors (each P greater than 0.05). Furthermore, MMP11 knockdown inhibited the proliferative activities and invasive potential of SGC-7901 GAC cells with decreased expression of IGF-1, PCNA and VEGF. Taken together, our findings demonstrated that MMP11 expression was increased in GAC tissues, but did not correlate with the clinicopathologic features. Knockdown of MMP11 expression could inhibit the proliferation and invasion of GAC cells probably through down-regulation of the IGF-1 signaling pathway, suggesting that MMP11 might be a potential therapeutic target for the treatment of gastric cancer.

Different effects of five catechins on 6-hydroxydopamine-induced apoptosis in PC12 cells

Five catechins [(-)-epigallocatechins gallate (EGCG), (-)-epicatechin gallate (ECG), (-)-epigallocatechin (EGC), (-)-epicatechin (EC), and (+)-catechin (C)] were compared with regard to their effects on 6-hydroxydopamine (OHDA)-induced apoptosis in PC12 cells--the vitro model of Parkinson's disease. Measured by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, 6-OHDA inhibited cell viability in a time- and concentration-dependent manner. When PC12 cells were pretreated with the five catechins for 30 min before exposure to 250 microM 6-OHDA, MTT results showed that the five catechins had different effects: EGCG and ECG had obvious concentration-dependent protective effects at 50-400 microM; EC and (+)-C had almost no effects; and EGC especially decreased cell viability. Catechins also had different effects on apoptotic morphology. Only 200-400 microM EGCG and ECG kept cells adhering well. When pretreated with other catechins at any concentration, PC12 cells became round and some of them were detached as when treated with 6-OHDA. In addition, typical apoptotic characteristics of PC12 cells were determined by fluorescence microscopy, flow cytometry, and DNA fragment electrophoresis after the cells were treated with 250 microM 6-OHDA for 24 h or pretreated with catechins before it. Preincubation with 200-400 microM EGCG and ECG led to significant inhibitory effects against PC12 cell apoptosis, as shown by flow cytometry. The other catechins have little protective effect. Therefore, at 200-400 microM, the classified protective effects of the five catechins were in the order ECG > EGCG >> EC > (+)-C > EGC. The data also indicated that EGCG and ECG might be potent neuroprotective agents for Parkinson's disease. The results of fluorescence microscopy and DNA fragment analysis supported the conclusion.

[The biochemical properties of L-arginine/nitric oxide pathway in rat brain mitochondria]

Biochemical property of L-arginine (L-Arg)/nitric oxide synthase (NOS)/nitric oxide (NO) system was observed in rat brain mitochondria. The results showed that there existed L-Arg transporters of high-affinity, low-transport and saturability in mitochondria membrane of normal rat brain. The maximum transport velocity (V(max)) and Michaelis constant (Km) were 5.87+/ -0.46 nmol/mg pro x min(-1) and 7.8+/- 0.56 micromol/L respectively. In normal condition, endothelium-type NOS was expressed in the mitochondria of rat brain, with its V(max) and Km being 2.7+/-0.3 nmol/mg pro x min(- 1) and 20.85+/-3.27 micromol/L, respectively. NO production was increased in a time-dependent manner and reached a maximum value at 60 min. These results suggest that the L-Arg transporters in MT membrane of normal rat brain were similar with Y(+) type amino acid transporters in cellullar membrane. Furthermore the NOS of mitochondria belongs to eNOS, whereas the L-Arg/NOS/NO system may be a source of NO.

[Determination of catechins in grape seeds by capillary electrophoresis]

A capillary zone electrophoresis (CZE) method has been developed for the determination of four pharmacologically active catechins in grape seed. The components analyzed were (+)-catechin, (-)-epicatechin, epigallocatechin and epicatechin gallate. Separation was achieved by using a mixed buffer of 0.02 mol/L borate and 0.005 mol/L phosphate at pH 10.0 as background electrolyte and an uncoated fused silica capillary with 50 microns i.d. x 375 microns o.d. (effective length 41.5 cm) maintained at 25 degrees C. The applied voltage was 25 kV, and detection was performed by DAD at wavelength of 210 nm. By using proposed CZE method, four catechins were well separated within only 10 minutes with the repeatability of < 1% RSD for migration time and < 5% RSD for peak area. Correlation coefficients better than 0.995 were obtained within the concentration range from 0.005 g/L to 0.5 g/L for the four analytes studied with the detection limit of 3 mg/L-10 mg/L. The contents of these compounds in ten species of grape seeds cultivated in China were successfully determined.

Chinonin, a novel drug against cardiomyocyte apoptosis induced by hypoxia and reoxygenation

The inhibitory effects of Chinonin, a natural antioxidant extracted from a Chinese medicine, on apoptotic and necrotic cell death of cardiomyocytes in hypoxia-reoxygenation process were observed in this study. The possible mechanisms of Chinonin on scavenging reactive oxygen species and regulating apoptotic related genes bcl-2 and p53 were also investigated. Neonatal rat cardiomyocytes were subjected to 24-h hypoxia and 4-h reoxygenation. Cell death was evaluated by DNA electrophoresis on agarose gel, cell death ELISA and annexin-V-FLUOS/propidium iodide (PI) double staining cytometry. Hypoxia caused the increase of apoptotic rates and the release of lactate dehydrogenase (LDH), while reoxygenation not only further increased the apoptotic rates and leakage of LDH, but also induced necrosis of cardiomyocytes. In addition, hypoxia increased the levels of NO(2)(-)/NO(3)(-) and thiobarbituric acid reacted substances (TBARS), while reoxygenation decreased NO(2)(-)/NO(3)(-), but further increased TBARS in the cultured media. Moreover, hypoxia up-regulated the expression levels of bcl-2 and p53 proteins, while reoxygenation down-regulated bcl-2 and further up-regulated p53. Chinonin significantly decreased the rates of apoptotic and necrotic cardiomyocytes, and inhibited the leakage of LDH. It also diminished NO(2)(-)/NO(3)(-) and TBARS, down-regulated the expression level of p53 protein, and up-regulated bcl-2 protein, respectively. The results suggest that Chinonin has preventive effects against apoptotic and necrotic cell death and its protective mechanisms are related to the antioxidant properties of scavenging nitric oxide and oxygen free radicals, and the modulating effects on the expression levels of bcl-2 and p53 proteins.

Protective effects of sodium tanshinone IIA sulphonate against adriamycin-induced lipid peroxidation in mice hearts in vivo and in vitro

Protective effects of sodium tanshinone IIA sulphonate against adriamycin-induced lipid peroxidation were investigated. Data showed that treatment with sodium tanshinone IIA sulphonate could prevent mice from decrease in body weight caused by adriamycin. It was found that myocardial lipid peroxidation in sodium tanshinone IIA sulphonate-treated mice was lower compared with that in adriamycin-treated ones. The activities of some endogenous antioxidant enzymes, such as superoxide dismutase, glutathione peroxidase and catalase, were higher in the sodium tanshinone IIA sulphonate group than that in the adriamycin group. In vitro experiments showed that sodium tanshinone IIA sulphonate could inhibit adriamycin-induced mitochondrial lipid peroxidation and swelling. Sodium tanshinone IIA sulphonate could scavenge adriamycin semiquinone free radical in heart homogenate dose-dependently. Thus, protective effects of sodium tanshinone IIA sulphonate may not only be related to its antioxidant activity but also to its regulation of antioxidant enzyme activities in the heart.

Two-peak kinetic curve of the chemiluminescence in phorbol-induced macrophage

Phorbol-1,2-myristate-1,3-acetate can induce rat macrophage to emit chemiluminescence. The kinetic curve of the chemiluminescence clearly showed two peaks when a proper ratio of phorbol-1,2-myristate-1,3-acetate and macrophage were mixed. It was proved that the first one mainly came from the oxygen free radicals and the second one from NO generated in the phorbol-1,2-myristate-1,3-acetate stimulated cells by using the substitute and inhibitor of NO synthase.

Studies on nitric oxide free radicals generated from polymorphonuclear leukocytes (PMN) stimulated by phorbol myristate acetate (PMA)

The interaction of NO and O2- free radicals generated from PMA (phorbol myristate acetate)-stimulated PMN (polymorphonuclear leukocytes) was studied by a nitroxide spin trap, DMPO (5,5-dimethyl-1-pyrroline-1-oxide). It was found that addition of L-arginine to the system would significantly decrease the trapped O2- by DMPO and addition of NG-monomethyl-arginine (NGMA) would significantly increase the trapped O2- by DMPO. It was proved that the formation of ONOO- by the reaction of NO and O2- was the main reason for the decrease of trapped O2- in the experiment with xanthine/xanthine oxidase and irradiation of riboflavin systems. The yield of NO during this process was calculated. The generation dynamic of NO was studied by a luminol-dependent chemiluminescence technique and it was found that after stimulation of PMN by PMA, there would be an immediate, significant chemiluminescence, which came mainly from the active oxygen free radicals generated by PMN. If L-arginine was added to this system, the chemiluminescence would increase about 100-fold, but NGMA inhibited the increase of the chemiluminescence. Ten minutes after addition of L-arginine, this increase did not change, the chemiluminescence peak decreased gradually, but the half life increased. The ESR and chemiluminescence properties of NO and ONOO- synthesized were also studied in model systems.

Scavenging effects of salvia miltiorrhiza on free radicals and its protection for myocardial mitochondrial membranes from ischemia-reperfusion injury

Using low temperature electron spin resonance (ESR) technique, we found that Salvia miltiorrhiza injection could scavenge the oxygen free radicals generated from ischemia-reperfusion injury in the myocardium as effectively as SOD. Using ESR spin trapping technique we found that one of its effective components, Danshensu, could scavenge superoxide anion free radicals generated from the reaction system of xanthine and xanthine oxidase, and that lipid free radicals generated from lipid peroxidation of myocardial mitochondrial membranes could be scavenged by another effective component, Tanshinone. The membrane fluidity of the mitochondria isolated from the ischemia-reperfused hearts was studied with the ESR spin labelling technique, and the TBA-method was used to detect the lipid peroxidation. It was found that Danshensu could protect the mitochondrial membrane from the ischemia-reperfusion injury and lipid peroxidation.

[Mechanism of scavenging effects of (-)-epigallocatechin gallate on active oxygen free radicals]

The concentration of 50% scavenging ratio (SC50) and the scavenging rate constants (k) and stiochiometric factor (n) were determined when (-)-epigallocatechin gallate [(-)-EGCG] scavenging superoxide anion free radical (O2.-) and hydroxyl radical (.OH). The mechanism of scavenging active free radicals of (-)-EGCG and the promotion of (-)-EGCG free radical and its structure were analyzed in vitro. Our results suggest that the centers of scavenging reaction of (-)-EGCG are B, D, and A cycles, and each (-)-EGCG traps six O2.- or .OH. It is in accord with the value of stiochiometric factor n = 6.

Scavenging effects of tetramethylpyrazine on active oxygen free radicals

The scavenging effects of tetramethylpyrazine (ligustrazine, Lig) isolated from Ligusticum wallichii Franch on active oxygen free radicals were studied using spin trapping technic and chemiluminescence methods. The scavenging rate of superoxide anion (O2-.) by Lig (25 mg.ml-1) was 100% in xanthine/xanthine oxidase (Xan/XO) system, and that of hydroxyl radical (OH-.) was 44% in Fenton's reaction. The scavenging rate of lipid peroxyl radical (LOO-.) by Lig (25 mg.ml-1) was 80% in peroxidizing microsome system. It is possible that Lig scavenged O2-. by catalyzing its spontaneous dismutation. The results showed that Lig had strong effects of scavenging cyotoxic oxygen free radicals (O2-., LOO-., OH-.).

[A study on the protective effect of metallic chelators on ischemia-reperfusion injury of isolated rat heart]

A Langendorff isolated rat heart preparation was used to determine the effect of the metallic chelators, deferoxamine and penicillamine on the extent of myocardial ischemia reperfusion injury. Each heart was subjected to 15-60 minutes of total ischemia at 37 degrees C followed by 15-60 minutes of reperfusion with either saline, deferoxamine (0.61 mmol/L), or penicillamine (30 mmol/L) treated perfusate. Reperfusion injury was assessed by the production of free radicals with electronic spin resonance spectroscopy and spin trap PBN, by the amount of creatine phospholipase released into the perfusate, by the changes in the myocardial vascular resistance, and by pathologic examination of myocardium. The results showed that the drug treated groups released significantly less radical adducts of PBN (P < 0.01) and creatine phosphokinase into the perfusate than the saline treated group (P < 0.01). The mean vascular resistance significantly increased in the saline treated group than in the drug treated groups (P < 0.01). Ultrastructural examination showed prominent attenuation of mitochondrial swelling in drug treated groups in comparison with the saline one. These findings indicated that both deferoxamine and penicillamine can protect the isolated rat heart from ischemia reperfusion injury. The possible mechanism of which is that metallic chelators block the transitional metal-catalyzed fenton reaction, and subsequently decrease the production of hydroxyl radical.

Scavenging effect of catechin on free radicals studied by molecular orbital calculation

The eigenvectors, net charges, and electron population on catechin were calculated with molecular orbital method MNDO. It was found that the 2 hydroxyls on the benzene ring of the chromane were more active than the others on the other benzene ring when it reacted with a free radical.

Effects of oxygen radicals on the conformation of sulfhydryl groups on human polymorphonuclear leukocyte membranes

The healthy intact polymorphonuclear leukocytes (PMNs) were labeled with 4-maleimide-TEMPO spin labeling compound (MAL) to study the effects of oxygen radicals produced by phorbol myristate acetate (PMA)-stimulated PMNs on the conformation of sulfhydryl (SH) groups of PMN membrane proteins. The lipid peroxidation induced by PMA-stimulated PMNs was detected by evaluating the formation of malonaldehyde (MDA) with the thiobarbituric acid (TBA) test. From the experiments of luminol-dependent chemiluminescence (CL) and fluorometry, it was found that Chinese herbs schizandrin B (Sin B) and quercetin (Q) possessed scavenging properties for oxygen radicals produced during the PMN respiratory burst. These two herbs can also inhibit the conformation changes in SH binding sites on the PMN membrane proteins caused by oxygen radicals produced by the PMNs themselves. They also decreased the amount of MDA, which was a final product formed during lipid peroxidation.

ESR spin trapping studies on the free radicals in gasphase of cigarette smoking

Free radicals in the gasphase of cigarette smoke were determined by spin trapping agent PBN (N-tert-butyl-2-phenyl nitrone) and DMPO (5,5-dimethyl-1-pyrroline-oxide) on electron spin resonance spectrometer. They were identified according to the spectrum parameters calculated from the spectra. The free radicals mainly consist of alkoxyl and alkyl free radicals, of which alkoxyl free radicals make up 60-70% of the total spectral components. These free radicals are very active and reactive. They can damage cells and lead to some diseases. This work points out the importance of scavenging the free radicals of cigarette smoke to prevent diseases caused by them.

[Scavenging of probimane on semiquinone free radical formation by doxorubicin in rat heart]

Probimane, dl-bis (4-morpholin-methyl 3,5-dioxopipweazin-1-yl) propane first synthesized in China, is a dioxopiperazin compound with antineoplastic, antimetastatic and radiopotentiating activities. In order to evaluate the mechanisms of cardiotoxicity protective action of probimane, the free radical induced by doxorubicin were analysed by electron spin resonance (ESR) techniques. Our studies showed that doxorubicin stimulated the formation of semiquinone free radicals in the rat heart homogenate and heart cell mitochondria systems, and probimane inhibited the free radical formation in both systems, with the dose-dependent and time-dependent responses. The inhibitory rates of doxorubicin free radical formation in rat heart homogenate system by probimane 0.6 mmol.L-1 at time of 3, 5, 10, 15, 30, 45 and 60 min were 44.6%, 43.0%, 51.5%, 74.3%, 68.1%, 56.1% and 39.9% respectively. The inhibitory rates of semiquinone free radical formation in mitochondria system by probimane at the concentration of 0.02, 0.06, 0.6, 1.2 and 2.4 mmol.L-1 were 17.07%, 29.87%, 63.95%, 64.62% and 83.64%, respectively. Probimane had no effect on NADH2, but inhibited NADH dehydrogenase activity at higher concentration.

Lymphocytes can produce respiratory burst and oxygen radicals as polymorphonuclear leukocytes

The respiratory burst and production of oxygen radicals by lymphocytes stimulated with phorbol myristate acetate (PMA) was studied and compared with that of polymorphonuclear leukocytes (PMN) by electron paramagnetic resonance (EPR) and spin trapping technique. Superoxide anion and hydroxyl radicals spin adducts of DMPO were detected in the stimulated PMN system, but only hydroxyl radical spin adducts of DMPO were detected in the stimulated lymphocyte system. It was proved by superoxide dismutase (SOD) and catalase that the hydroxyl radicals produced in the stimulated lymphocyte system came from superoxide anions, just like the hydroxyl radicals produced in the stimulated PMN.

Active oxygen radicals produced by leukocytes of malignant lymphoma

The electron spin resonance (ESR) spectra of active oxygen radicals produced during the respiratory burst of PMA-stimulated leukocytes and oxygen consumption are studied by ESR spin trapping and spin probe oxymetry for 31 times in 17 cases of malignant lymphoma. The results showed that the spectra produced from PMA-stimulated patients' leukocytes were predominantly spin adducts of DMPO-hydroxyl radicals (DMPO-OH). The decrease in oxygen consumption during respiratory burst suggested that respiratory burst function was inhibited. Kinetic observations of patient condition showed that respiratory burst and oxygen consumption were improved and even approached normal, when the patient was in remission or the condition was ameliorated. This paper is the first of its type and helps clarify the mechanism of malignant proliferation and metastasis.

Detection of free radical scavenging activity of schisanhenol by electron spin resonance

It was reported that Schisanhenol (Sal) isolated from Schisandrae Rubriflora inhibited lipid peroxidation induced by ferrous-cysteine and NADPH-ascorbic acid. In this studies the oxygen radical scavenging activity of Sal was detected by electron spin resonance (ESR) and spin trapping. Sal was shown to scavenge oxygen radicals produced by human neutrophils (Neu) stimulated by tetradecanoylphorbol acetate (TDPA). But no effect of Sal was seen on oxygen consumption measured by spin label oximetry in Neu during respiratory burst. In Fenton reaction system, the inhibitory rate of hydroxyl radical by Sal was 34.4%. In xanthine-xanthine oxidase and uv-irradiation of riboflavin systems, Sal scavenged superoxide anion radical by 26.1% and 21.9%, respectively. In all these systems the action of Sal was more potent than that of vitamin E. It may be concluded that Sal possesses a free radical-scavenging activity.

[Scavenging effects of sodium ferulate and 18 beta-glycyrrhetic acid on oxygen free radicals]

The scavenging effects of sodium ferulate (SF) and glycyrrhetic acid (GA) on oxygen free radicals were studied by using spin trapping technique and chemiluminescence (CL) methods. SF 0.3 mmol/L and GA 0.3 mmol/L effectively scavenged oxygen free radicals produced by phorbol myristate acetate (PMA)-stimulated polymorphonuclear leukocytes (PMN), but had no effect on the oxygen consumption by PMN, measured with spin probe oxymetry. In 3 cell-free oxygen free radical generating systems, both SF and GA showed a remarkably scavenging effects on O2- and OH.. SF 30 mumol/L and GA 30 mumol/L prominently inhibited the CL response of PMA-stimulated PMN. The results demonstrated that SF and GA are oxygen free radical scavengers.

Scavenging effect of berbamine on active oxygen radicals in phorbol ester-stimulated human polymorphonuclear leukocytes

The scavenging effect of berbamine (Ber) on active oxygen radicals was studied, using a spin-trapping technique and a chemiluminescence (CL) method in phorbol myristate acetate (PMA) stimulated polymorphonuclear leukocytes (PMN) and in four cell-free superoxide (O2-.) or hydroxyl radical (OH.) generating systems. Ber (0.1 to 0.3 mM) effectively reduced active oxygen radicals in PMN stimulated with PMA, but had no obvious effect on oxygen consumption during the respiratory burst of PMN, measured with spin probe oxymetry. Ber (0.3 mM) prominently inhibited the CL response of PMA-stimulated PMN. The agent remarkably quenched O2-. in xanthine/xanthine oxidase and irradiation riboflavin systems and OH. in the Fenton reaction. Its scavenging action on O2-. was stronger than that of Vitamin E in the xanthine/xanthine oxidase system but the same as Vitamin E in the riboflavin system, and its action on OH. was similar to that of Vitamin E.

Scavenging effect of schizandrins on active oxygen radicals

The reactive oxygen radicals produced from human polymorphonuclear leukocytes (PMN) stimulated with PMA (phorbol myristate acetate), hydroxyl radicals generated by a Fenton reaction, and superoxide anion radicals produced by irradiating solutions of riboflavin in the presence of EDTA have been taken as the models for production of oxygen radicals. With the use of the electron spin resonance spin trapping method, the scavenging effects of schizandrol A (solA) (5 x 10(-4) M) and schizandrin B (sinB) (5 x 10(-4) M) have been studied and compared with the effects of vitamin E (5 x 10(-4) M) and vitamin C (5 x 10(-4) M). It has been found that in cell system the scavenging effects of sinB and solA, as judged by ESR spin trappings, on hydrpxyl radicals (.OH) are greater than vitamin E and vitamin C and the scavenging effects on superoxide anion (O2) are greater than vitamin E but lower than vitamin C. With respect to the Fenton reaction, sinB has the strogest scavenging effect on .OH (77%) and solA has strong scavenging effect on .OH (63%), both of them larger than that of vitamin E (35%) and vitamin C (56%). In the riboflavin/EDTA system, the scavenging effect of sinB (46%) is smaller than that of vitamin C (96%) but larger than that of vitamin E (23%); the scavenging effect of solA is not obvious (14%). With the use of spin probe oximetry, the oxygen consumption during the respiratory burst of stimulated PMN has been measured when exposed to schizandrins. The experiment results demonstrated that they do not affect the activity of production of active oxygen radicals in the respiratory burst of PMN stimulated with PMA.

Scavenging effects on active oxygen radicals by schizandrins with different structures and configurations

We have studied the scavenging effects of different structures and configurations of schizandrins isolated from Fructus Schizandrae, a traditional Chinese herb, on active oxygen radicals with the method of spin-trapping technique. The active oxygen radicals were produced from human polymorphonuclear leukocytes (PMN) stimulated with phorbol myristate acetate (PMA). In addition, the scavenging effects of schizandrins on hydroxyl radicals (.OH) in Fenton's reaction and the scavenging effects on superoxide anions (O2-.) in both riboflavin/EDTA and xanthine/xanthine oxidase systems have also been studied. They are compared with the scavenging effects of both Vitamin C (Vc) and Vitamin E (VE). The experimental results have shown that the scavenging effect of schizandrin B (Sin B) on the active oxygen radicals is stronger than that of S(-) Sin B and R(+) Sin B. For schizandrins of the same molecular structures with different stereoconfigurations the scavenging effects of S type of the benzene ring on active oxygen radicals are stronger than those of R type and for schizandrins of the same stereoconfigurations with different structures the scavenging effects of schizandrin C (Sin C) on the active oxygen radicals are stronger than those of Sin B.

[Scavenging effects of probimane on active oxygen free radicals by electron spin resonance]

Probimane, dl-1,2-bis (4-morpholine-methyl-3, 5-dioxopiperazin-1-yl) propane, is a new antitumor agent synthesized by Shanghai Institute of Materia Medica, Chinese Academy of Sciences. The scavenging effects of probimane on active oxygen radicals produced in 3 different systems were studied with the ESR spin trapping methods. In Fenton's reaction, probimane remarkably scavenged hydroxyl radicals (.OH) and the rate of scavenging .OH by probimane 0.05 mmol/L was 47%, compared to 5% by vitamin E (VE) and 30% by ascorbic acid (AA). In irradiation riboflavin system, in which superoxide (O2-.) was produced, the agent also had the scavenging effects on O2(-.). The rate of scavenging O2-. by probimane 0.05 mmol/L was 13%, higher than that by VE (7%) but lower than that by AA (90%). In cell system where the active oxygen radicals were produced during the respiratory burst of human neutrophils (Neu) stimulated by TPA (tetradecanoylphorbol acetate), probimane exhibited a dose-dependent scavenging action on the radicals. The rate of the radical scavenging by probimane 0.05 mmol/L was 37%, much higher than that by VE (9%) but lower than that by AA (68%). Probimane had no effect on the rate of oxygen consumption by human Neu, measured with spin probe oxymetry.

[Direct detection of oxygen free radicals produced by myocardial reperfusion using electron spin resonance spectroscopy]

There is a growing evidence for the role of oxygen free radicals (OFR) in mediating myocardial tissue injury during myocardial ischemia and particularly during reperfusion. But almost all of the evidence was indirect, using electron spin resonance (ESR) spectroscopy, we have directly measured OFR generated in ischemic and reperfused isolated rabbit hearts. 17 hearts were rapidly frozen in liquid nitrogen after their arrest by cardioplegic solution and sampled after 150 min of sustained hypothermic global ischemia or after reperfusion. The ESR spectra obtained from experiment have directly demonstrated that OFR is produced in significant amounts in the isolated rabbit hearts during early stage of reperfusion but only small amount during ischemia. The mitochondrial electron transport chain appeared to be the main source of OFR. We found that superoxide dismutase scavenged OFR generated during reperfusion efficiently, but catalase did not. We believe that superoxide anion, not hydroxyl radical, is the main OFR which is responsible for myocardial reperfusion injury. We also found that Salvia, a traditional Chinese medicine, a very efficient OFR scavenger, had the similar effect as superoxide dismutase.

ESR studies on active oxygen radicals produced in the respiratory burst of human polymorphonuclear leukocytes

The mechanism and process of production of active oxygen radicals in the respiratory burst of polymorphonuclear leukocytes (PMN) stimulated with PMA (phorbol myristate acetate) was studied in this paper. The experimental results indicate that when the PMA was dilute enough or at the beginning of stimulation even when the PMA concentration was high, the spectrum of hydroxyl radical spin adducts, DMPO-OH, was dominant in the ESR spectra. However, at the maximum level of the respiratory burst, the spectrum of superoxide anion spin adducts, DMPO-OOH, was dominant.

ESR studies on oxygen consumption during the respiratory burst of human polymorphonuclear leukocytes

Oxygen consumption during the respiratory burst of human polymorphonuclear leukocytes (PMN) stimulated with phorbol myristate acetate (PMA) was studied with spin probe oxymetry and using the transition metal ion CrOX (potassium trioxalatochromate) as a widening agent. The experimental results demonstrated that during the respiratory burst of PMN stimulated with PMA, oxygen consumption was found mainly in the intercellular medium but no change of oxygen concentration was found in the intracellular medium.

Scavenging effect of extracts of green tea and natural antioxidants on active oxygen radicals

With the use of the spin trapping methods, the scavenging effects of the extracts of green tea and other natural foods are studied. In stimulated polymorphonuclear leukocytes (PMN) system, water extract fraction 6 (F6) from green tea and green tea polyphenols (GTP) have the strongest scavenging effect on the active oxygen radicals, much stronger than vitamin C (Vc) and vitamin E (VE). Rosemary antioxidants (RA) and Curcumin (Cur) have weaker scavenging effects than Vc, but stronger than VE. In Fenton Reaction, Cur has the strongest scavenging effect (69%) on hydroxyl radicals. In irradiation, riboflavin system F6(74%) and GTP(72%) have very strong scavenging effects that are weaker than Vc, but much stronger than VE (23%). With the use of spin probe oxymetry, the oxygen consumption in respiratory burst of stimulated PMN were measured when the antioxidants existed in these systems. The results demonstrated that these antioxidants did not affect the respiratory burst of human polymorphonuclear leukocytes stimulated with PMA.

Spin-label and fluorescence labeling studies of the thioester bonds in human alpha 2-macroglobulin

Upon cleavage of the reactive thioester bonds (Cys-949-Glx-952) of tetrameric human alpha 2-macroglobulin (alpha 2M) by methylamine, one sulfhydryl group per alpha 2M subunit is exposed. These identical sulfhydryl group sites were labeled with the thiol-specific nitroxide spin-labels (1-oxy-2,2,5,5-tetramethyl-3-pyrrolin-3-yl)methyl methanethiosulfonate and (1-oxy-2,2,6,6-tetramethyl-4-piperidinyl)methyl methanethiosulfonate, a homologous series of maleimide spin-labels, and the thiol-specific fluorescent probe 2-[(4-maleimidophenyl)amino]naphthalene-6-sulfonic acid sodium salt (MANS). The ESR and fluorescence results showed that these sulfhydryl group sites were at the base of a narrow crevice that is greater than or equal to 8 A deep. Although the bound MANS fluorophore was slightly blue shifted with an enhanced quantum yield vs the free label in water, the environment of the sulfhydryl site appeared to be of a polar nature when compared with the emission maxima in several solvents of varying polarity. The Glx residue participating in the thioester linkage in the intact protein was labeled with 4-amino-2,2,6,6-tetramethylpiperidine-1-oxyl. The distance between the Glx and Cys moieties was estimated at greater than or equal to 10-25 A from double spin-labeling experiments.

Studies on the property of sulfhydryl binding site on the lung normal and cancer cell membrane of Chinese hamster with maleimide spin labels

In this paper, five maleimide spin labels with different chain lengths were used to study the properties of binding sites of sulfhydryl groups on the membrane proteins of normal cell V79 and cancer cells V79-B1 in the lung of Chinese hamster. The ratio of the strongly immobilized component to the weakly immobilized component (s/w) and the rotational correlation time (tau c) were calculated on the basis of ESR spectra. From the varying of the s/w and tau c with the chain lengths of spin labels it was deducted that the binding sites of sulfhydryl groups on V79 and V79-B1 membrane proteins were of conical shape and that the binding sites of sulfhydryl groups on V79 membrane protein were deeper and narrower than those on V79-B1.