[Effect of obstructive sleep apnea on cardiopulmonary function in patients with chronic obstructive pulmonary disease]

Objective: To study the characteristics of cardiopulmonary function in patients with chronic obstructive pulmonary disease (COPD) and obstructive sleep apnea (OSA) overlapping syndrome (OS). Methods: A total of 149 COPD patients, who were on stable treatment, were enrolled from the Second Affiliated Hospital of Soochow University from December 2017 to December 2019. The patients were divided into the OS group (n=56) and the COPD only group (n=93) according to their apnea hypopnea index (AHI) measured by the Apnealink device. Data were gathered from polysomnograph (PSG), spirometry, arterial blood gas and N-terminal pro-brain natriuretic peptide (NT-proBNP) assay to assess the cardiopulmonary function of patients. Partial correlation analysis was used to analyze the correlation between AHI and various factors, to study the characteristic changes in the cardiopulmonary function of these OS patients. Results: There were no significant cross-group differences in age and gender (all P>0.05). In the OS group, the forced expiratory volume in one second to forced vital capacity ratio (FEV₁/FVC), the forced expiratory volume in the first second expressed as percent predicted (FEV₁%pred), pH[M (Q₁, Q₃)], partial pressure of oxygen (PaO₂) and oxygen saturation (SaO₂) were lower than those in the COPD group [(49.46±12.98)% vs (54.38±11.72)%, (47.86±14.78)% vs (57.78±15.81)%, 7.37(7.34, 7.39) vs 7.40(7.39, 7.41), (80.75±10.20) vs (84.28±8.43) mmHg (1 mmHg=0.133 kPa), (94.46±2.52)% vs (95.74±2.28)%], whereas partial pressure of carbon dioxide (PaCO₂) [M (Q₁, Q₃)] was higher than that in the COPD group [55.00 (45.50, 60.00) vs 44.00(40.00, 48.00)mmHg] (all P<0.05). Pulmonary arterial pressure and plasma NT-proBNP levels [M (Q₁, Q₃)] in the OS group were significantly higher than those in the COPD group [38.90 (28.60, 49.05) vs 28.60 (24.95, 32.60) mmHg, 434.00 (273.75, 631.00) vs 136.00 (86.00, 205.00) pg/ml] (P<0.05). Partial correlation analysis showed that AHI was positively correlated with PaCO₂, pulmonary artery pressure, NT-proBNP, and acute exacerbation events (r values: 0.496, 0.544, 0.628, 0.446), and negatively correlated with FEV₁/FVC, FEV₁%pred, pH, PaO₂, and SaO₂ (r values:-0.309, -0.346, -0.410, -0.289, -0.267) (all P<0.05). Conclusion: Patients with OS suffer from more severe hypoxemia, hypercapnia and pulmonary function damage, and their pulmonary arterial pressure and NT-proBNP are significantly higher than those with COPD only.

[Risk factor analysis of the patients with solitary pulmonary nodules and establishment of a prediction model for the probability of malignancy]

Objective: This study aims to analyze the relationship among the clinical features, radiologic characteristics and pathological diagnosis in patients with solitary pulmonary nodules, and establish a prediction model for the probability of malignancy. Methods: Clinical data of 372 patients with solitary pulmonary nodules who underwent surgical resection with definite postoperative pathological diagnosis were retrospectively analyzed. In these cases, we collected clinical and radiologic features including gender, age, smoking history, history of tumor, family history of cancer, the location of lesion, ground-glass opacity, maximum diameter, calcification, vessel convergence sign, vacuole sign, pleural indentation, speculation and lobulation. The cases were divided to modeling group (268 cases) and validation group (104 cases). A new prediction model was established by logistic regression analying the data from modeling group. Then the data of validation group was planned to validate the efficiency of the new model, and was compared with three classical models(Mayo model, VA model and LiYun model). With the calculated probability values for each model from validation group, SPSS 22.0 was used to draw the receiver operating characteristic curve, to assess the predictive value of this new model. Results: 112 benign SPNs and 156 malignant SPNs were included in modeling group. Multivariable logistic regression analysis showed that gender, age, history of tumor, ground -glass opacity, maximum diameter, and speculation were independent predictors of malignancy in patients with SPN(P<0.05). We calculated a prediction model for the probability of malignancy as follow: p=e(x)/(1+ e(x)), x=-4.8029-0.743×gender+ 0.057×age+ 1.306×history of tumor+ 1.305×ground-glass opacity+ 0.051×maximum diameter+ 1.043×speculation. When the data of validation group was added to the four-mathematical prediction model, The area under the curve of our mathematical prediction model was 0.742, which is greater than other models (Mayo 0.696, VA 0.634, LiYun 0.681), while the differences between any two of the four models were not significant (P>0.05). Conclusions: Age of patient, gender, history of tumor, ground-glass opacity, maximum diameter and speculation are independent predictors of malignancy in patients with solitary pulmonary nodule. This logistic regression prediction mathematic model is not inferior to those classical models in estimating the prognosis of SPNs.

A QTL with Major Effect on Reducing Stripe Rust Severity Detected From a Chinese Wheat Landrace

Stripe rust, a devastating disease of wheat worldwide, can be controlled by use of diverse wheat resistance resources. To find new quantitative trait loci (QTL) for resistance to stripe rust, Qing Shumai (a Chinese winter wheat landrace possessing slow rusting resistance) was crossed with the susceptible line Mingxian 169. The parents and 276 recombinant inbred lines (RILs) from the cross were evaluated in five environments involving two locations (Gansu and Shandong provinces, China) and four autumn-sown wheat seasons (2008 to 2012). Disease severities on Qing Shumai were lower than 25%, contrasting with approximately 90% on Mingxian 169. The RILs varied in rust intensity in a continuous and monomodal distribution. A bulked segregant analysis approach using 2,344 simple sequence repeat (SSR) markers mapped a major QTL to the long arm of chromosome 6D (hereby designated as QYr.cau-6DL). An SSR marker (gpw5179, https://wheat.pw.usda.gov/GG2/index.shtml ) was identified as being tightly linked with QYr.cau-6DL. Combination between QYr.cau-6DL and the stripe rust-resistance gene Yr18 was examined using 160 F_2:3 families of Qing Shumai × RL6058 (a near-isogenic line for Yr18 in the genetic background of the spring wheat Thatcher). The combination elevated the resistance consistently across both winter and spring wheat backgrounds, acting synergistically without undesired epistasis.

Enhanced immunity and antiviral effects of an HBV DNA vaccine delivered by a DC-targeting protein

DNA vaccine targeting delivery to DC represents one effective strategy to improve the immunogenicity of the vaccine. In a previous study, we developed a novel DC-targeting recombinant protein that can deliver plasmid DNA to DCs by an electrostatic coupling effect and can thus improve the uptake efficiency of DCs, improving the expression of plasmid DNA in DCs. In this study, we coupled the protein with the HBV DNA vaccine pSVK-HBVA and investigated whether the immunogenicity and antiviral ability of the vaccine can be improved in HBV transgenic mice. The results show that a stronger specific immune response can be induced in mice after immunization with the coupling vaccine. The HBV DNA copy number and circulating antigen HBsAg in the serum of HBV transgenic mice were significantly decreased. Therefore, this study has demonstrated that the DC-targeting protein has the ability to improve the immunogenicity and the antiviral activity of the HBV DNA vaccine pSVK-HBVA. These findings indicate that this DC-targeting protein can be a potential method for the delivery of DNA vaccines directly to DCs.

An efficient [4+3] cycloaddition reaction of aza-o-quinodimethanes with C,N-cyclic azomethine imines: stereoselective synthesis of 1,2,4-triazepines

An efficient [4+3] cycloaddition reaction of in situ generated aza-o-quinodimethanes with C,N-cyclic azomethine imines has been developed.

Electronic structure, bonding and phonon modes in the negative thermal expansion materials of Cd(CN)(2) and Zn(CN)(2)

The disordered configuration, band structures, density of states, Mulliken population, elastic constants, zone center optic phonon modes and their Grüneisen parameters of M(CN)(2) (M =  Cd, Zn) have been studied for possible cyanide-ordering patterns by the first-principles plane-wave pseudopotential method based on density functional theory. Total energy calculations predict that MC(2)N(2)-MC(2)N(2) is the most favorable configuration for Cd(CN)(2) whereas all three possible configurations are near equally favorable for Zn(CN)(2). Effective charges and bond order analyses reveal that the M(CN)(2) (M =  Cd, Zn) frameworks include much stiffer [Formula: see text] and weaker M-C/N bonds, which account for the flexing of the M-CN-M linkage during the transverse motion of the cyanide-bridge. The transverse translational and the librational modes give rise to negative Grüneisen parameters and therefore contribute to the negative thermal expansion. Transverse vibrations of the C and N atoms in the same (transverse translational modes) or opposite (librational modes) directions have the same effect of drawing the anchoring metal atoms closer. Among all the optical phonon modes, the lowest-energy transverse translational optical modes which are neither Raman nor infrared active in Cd(CN)(2) and Zn(CN)(2) give rise to the largest contribution to the negative thermal expansion.

Decolorization of Direct Black 22 by Aspergillus ficuum

The decolorization of Direct Black 22 by Aspergillus ficuum has been studied. It was found that Aspergillus ficuum could effectively decolorize Direct Black 22 especially when grown as pelleted mycelia. Results showed that the media containing Direct Black 22 at 50 mg/L could be decolorized by 98.05% of the initial color in 24 h. The optimum pH and temperature of decolorization are 4.0 and 33 degrees C respectively. Aeration was quite beneficial to decolorization. Medium composition and the concentration of Direct Black 22 could affect the rate of decolorization. The dye degraded products assayed by UV-visible spectrophotometer and macroscopic observation showed that the decolorization of Direct Black 22 by mycelial pellets includes two important processes: bioadsorption and biodegradation. The degradation experiment agree with the Michaelis-Menten kinetics equation.

Inhibitory effects of indomethacin on interleukin-1 and nitric oxide production in rat microglia in vitro

Indomethacin, as a nonsteroidal antiinflammatory drug, is reported to be effective in some degree in the prevention and treatment of Alzheimer's disease (AD). Effects of indomethacin on proinflammatory cytokines interleukin-1 (IL-1), tumor necrosis factor alpha and nitric oxide (NO) on rat microglia in vitro were investigated. The biological activities of IL-1 were assayed by thymocyte proliferation assay and the activities of TNG-alpha, by L929 cytotoxicity assay. NO concentration was represented by nitrite and determined by Griess reaction. Indomethacin inhibited IL-1 and NO production by rat microglia stimulated at the concentration of 0.1-10 micromol/l. However, it did not show any inhibitory effect on TNF-alpha production by resting and LPS-stimulated rat microglia. The results suggest that the mechanism by which indomethacin might be beneficial in treatment of AD might be due to the inhibition IL-1 and NO production from microglia.

ATP-sensitive potassium channel activation mimics the protective effect of ischaemic preconditioning in the rat isolated working heart after prolonged hypothermic storage

1. Ischaemic preconditioning (IP) can significantly reduce the extent of infarct size, contractile dysfunction and necrosis in hearts from a number of animal species. Activation of ATP-sensitive potassium channels has been implicated in this process. The aims of the present study were to determine the extent to which IP preserves haemodynamic function in the rat isolated working heart model after prolonged hypothermic storage and to examine the involvement of activation of potassium channels in this process. 2. Hearts from Wistar rats were perfused on a Langendorff apparatus. After stabilization in working mode, baseline measurements of heart rate, aortic flow, coronary flow and cardiac output were performed. Hearts were randomized to one of six treatment groups: (i) untreated control; (ii) IP; (iii) 3 min perfusion with 200 mumol/L pinacidil; (iv) pinacidil vehicle; (v) 3 min perfusion with 10 mumol/L glibenclamide before IP; and (vi) 3 min perfusion with glibenclamide then pinacidil. Hearts were stored in an extracellular-based preservation solution for 6 or 12 h at 2-3 degrees C, remounted on the perfusion apparatus, stabilized as before and then haemodynamic measurements were repeated, after which time heart water contents were determined. 3. Recovery of haemodynamic function was markedly enhanced in the IP and pinacidil-treated groups compared with untreated and vehicle controls. These beneficial effects were completely blocked by glibenclamide. These results suggest that strategies for activating potassium channels in donor hearts may protect organs during hypothermic storage prior to transplantation.

Effects of ginkgolides on interleukin-1, tumor necrosis factor-alpha and nitric oxide production by rat microglia stimulated with lipopolysaccharides in vitro

The effects of ginkgolide A (CAS 15291-75-5, BN52020, GA) and B (CAS 15291-77-7, BN52021, GB) on interleukin (IL)-1, tumor necrosis factor-alpha (TNF-alpha) and nitric oxide (NO) production in resting and lipopolysaccharide (LPS)-stimulated neonatal rat microglia were studied. Apafant (CAS 105219-56-5), a platelet activating factor (PAF) antagonist of triazolobenzodiazepine type was used as control. The biological activities of IL-1 and TNF-alpha were tested by mouse thymocyte proliferation and L929 cytotoxicity assay, respectively. NO concentration was represented by nitrite and determined by Griess reaction. GA 1 nmol/1-10 mumol/l inhibited IL-1 production, and 100 nmol/l-10 mumol/l decreased TNF-alpha and NO production in dose-dependent manner. GB inhibited IL-1, TNF-alpha and NO production at the concentrations 10 nmol/l-10 mumol/l, 100 nmol/l-10 mumol/l and 10 nmol/l-10 mumol/l, respectively. Apafant inhibited IL-1, but not TNF-alpha and NO production. GB plus apafant (50 mumol/l) showed IL-1 and NO inhibitory effects, but not on TNF-alpha. The manner was different from that of GB or apafant alone. The results suggested that GA and GB inhibited proinflammatory cytokines and NO production from LPS-stimulated rat microglia, however, apafant inhibited IL-1 production only. The effects of GA and GB on proinflammatory cytokines and NO production from rat microglia do not seem to be based on PAF receptor antagonism. In addition, GA and GB are regarded as promising agents for the treatment of some neurodegenerative diseases in the central nervous system.

The nitric oxide donor, diethylamine NONOate, enhances preservation of the donor rat heart

BACKGROUND

Ischemia/reperfusion injury to transplanted organs may be associated with loss of endothelial release of nitric oxide. The aim of this study was to determine whether supplementation of an extracellular-based cardioplegic solution in routine clinical use at our institution with nitric oxide (as diethylamine NONOate) enhanced poststorage functionality of an isolated working heart model.

METHODS

Excised hearts were ligated to an aortic cannula and immediately perfused retrogradely with oxygenated Krebs solution at a hydrostatic pressure of 100 cm H2O at 37 degrees C. This preparation was then converted to a working system by switching the supply of perfusate from the aorta to a left atrial cannula at a filling pressure of 15 cm H2O. After a 1-minute stabilization period, baseline measurements of heart rate, aortic flow, coronary artery flow, and cardiac output were performed. Oxygenated cardioplegic solution (0.1 micromol/L), with or without NONOate, was then infused into the coronary circulation. Hearts were then stored in the same solutions for 6 or 12 hours at 2 degrees to 3 degrees C. The hearts were then remounted on the perfusion apparatus and reperfused as before, and hemodynamic measurements were repeated. Water content of the hearts were then determined.

RESULTS

Addition of the nitric oxide donor significantly improved all hemodynamic parameters measured after 12 hours storage and aortic flow at 6 hours storage compared with the untreated control groups. There was no significant difference between the water contents of the NONOate-treated and control groups.

CONCLUSIONS

The presence of the nitric oxide donor diethylamine NONOate was associated with significantly better preservation of coronary artery flow and cardiac function in the isolated rat heart after a 12-hour period of hypothermic storage and suggests a novel use for this family of compounds in the transplantation context.

Inhibitory effects of ginkgolides on nitric oxide production in neonatal rat microglia in vitro

AIM

To study the effects of ginkgolide A (GA) and B (GB), apafant (Apa), and N omega-nitro-L-arginine (L-NA) on nitric oxide (NO) production in cultured neonatal rat microglia.

METHODS

NO concentration was represented by nitrite which was determined by Griess reaction.

RESULTS

In resting microglia, no inhibitory effects of GA, GB, and Apa were observed. L-NA inhibited NO production, its IC50 value (95% confidence limits) being 3.4 (0.8-14.9) mumol.L-1. GA, GB, and L-NA inhibited NO production in LPS-stimulated microglia, and their IC50 values (95% confidence limits) were 5.7 (1.8-18.1), 1.1 (0.3-4.4), and 0.5 (0.1-2.8) mumol.L-1, respectively. Apa did not inhibit NO production.

CONCLUSION

GA and GB inhibited NO production in LPS-stimulated microglia.

Cardioprotective effects of pinacidil pretreatment and lazaroid (U74500A) preservation in isolated rat hearts after 12-hour hypothermic storage

BACKGROUND

Two important processes in the preservation of the function of donor hearts are the maintenance of ATP-sensitive potassium channel activity during myocardial ischemia and the scavenging of reactive oxygen species formed during reperfusion. The aim of this study was to compare the effect of three protocols on the preservation of hemodynamic function in isolated rat hearts after hypothermic storage. These protocols were: (1) pretreatment of the heart with a potassium channel opener (200 microM pinacidil); (2) storage of the heart in an aspartate-enriched extracellular cardioplegic solution containing the lazaroid antioxidant, U74500A (30 microM); and (3) a combination of protocols 1 and 2.

METHODS

Hearts from Wistar rats were perfused on a Langendorff apparatus. After stabilization in working mode, baseline measurements of heart rate, coronary and aortic flow, and cardiac output were performed. Hearts (n=6 in each group) were then randomized to protocols 1-3, untreated controls, or vehicle-treated controls. Hearts were stored in extracellular-based preservation solution for 12 hr at 2-3 degrees C, remounted on the perfusion apparatus, and stabilized as before; hemodynamic measurements were then repeated.

RESULTS

Recovery of hemodynamic function was enhanced by pinacidil pretreatment or incorporation of lazaroid in the storage solution, but the combination of these two treatments produced the best results.

CONCLUSIONS

Combined pharmacological activation of ATP-sensitive potassium channels before cardioplegia and the addition of U74500A to the preservation solution is associated with significantly enhanced hemodynamic function in the isolated rat heart after 12 hr of hypothermic storage. These data suggest a novel use for these agents in the transplantation context.

Cytokine and nitric oxide production by rat microglia stimulated with lipopolysaccharides in vitro

AIM

To study the characterization of interleukin (IL)-1, IL-2, tumor necrosis factor-alpha (TNF-alpha), and nitric oxide (NO) production in microglia stimulated with lipopolysaccharides (LPS).

METHODS

Primary cultured neonatal rat microglia were incubated with LPS (0-10 mg.L-1) for 0-72 h. The supernatants and lysates were collected. IL-1, IL-2, and TNF-alpha were assayed by mouse thymocyte proliferation, mouse spleen cell proliferation, and 1929 cytotoxity, respectively. NO was assayed by Griess reaction.

RESULTS

Extracellular IL-1, TNF-alpha, and NO production reached peak levels at LPS 1 mg.L-1. Intracellular IL-1 production reached its peak level at LPS 100 micrograms.L-1. Intracellular TNF-alpha level was very low. IL-1, TNF-alpha, and NO activities were detected at 1, 4, and 8 h, after the cells were stimulated with LPS. IL-1 got to its peak value at 8 h, TNF-alpha, and NO reached the highest levels at 24 h. However, IL-2 activity was not detected after the microglia were stimulated with LPS 0-10 mg.L-1 during the incubation period.

CONCLUSION

Rat microglia stimulated with LPS in vitro produced proinflammatory cytokines and NO.

Ischemic preconditioning enhances donor lung preservation in the rat

BACKGROUND

Ischemic preconditioning achieved by brief periods of ischemia and reperfusion before a prolonged period of ischemia can significantly reduce the extent of cardiac damage in many mammalian species and human beings. In this study we used a rat model of single lung transplantation to show that ischemic preconditioning also occurs in the lung.

METHODS

Rats randomly selected for ischemic preconditioning had their left main bronchus and pulmonary artery occluded for 5 minutes, followed by 10 minutes of reperfusion and ventilation. Lungs of control rats were ventilated for 15 minutes. The lungs were perfused with University of Wisconsin solution, then heart and lungs were excised en bloc and stored in University of Wisconsin solution at 0 degree C for 6 or 12 hours. After left pneumonectomy, the left lung of the donor was then implanted into the recipient via left thoracotomy. After 1 hour of ventilation and reperfusion, a right pneumonectomy was performed making the animal completely dependent on the transplanted lung. Samples of arterial blood from the left ventricle were then taken for arterial oxygen tension and arterial carbon dioxide tension determination. Water contents of the donor lungs were measured before and after reperfusion. Thiobarbituric acid reactive substances were measured in the right donor lung after storage.

RESULTS

Lungs transplanted after 12 hours of storage had profoundly impaired gas exchange (arterial oxygen tension = 34 +/- 5; arterial carbon dioxide tension = 69 +/- 7 mm Hg) compared with the normal levels in the 6-hour storage group (arterial oxygen tension = 308 +/- 22; arterial carbon dioxide tension = 17 +/- 1 mm Hg). Ischemic preconditioning significantly improved gas exchange in the 12-hour storage group (arterial oxygen tension = 83 +/- 11; arterial carbon dioxide tension = 40 +/- 4 mm Hg). Ischemic preconditioning also significantly decreased thiobarbituric acid reactive substances formation at both 6- and 12-hour storage.

CONCLUSIONS

These results show that the phenomenon of ischemic preconditioning occurs in the lung and that it may reduce injury to the donor lung during prolonged cold ischemic storage.

Selective inhibition of nitric oxide production during cardiac allograft rejection causes a small increase in graft survival

Nitric oxide production is increased in allograft rejection and may have both beneficial and deleterious effects on graft function and survival. In animal models, conventional immunosuppressive agents have been shown to decrease nitric oxide production. The aim of our study was to determine what effect augmentation and selective inhibition of nitric oxide production may have on graft survival by using the model of heterotopic cardiac transplantation in the rat. L-Arginine, the naturally occurring substrate for nitric oxide production, was administered subcutaneously at 200 mg/kg/day. L-NG-monomethyl-L-arginine (L-NMMA) is a selective inhibitor of nitric oxide synthase and was administered at 500 mg/kg/day to allograft recipients from the day of operation. Endogenous nitric oxide production was quantified by analysis of urinary nitrate excretion, and time to rejection was determined by graft palpation. L-Arginine did not significantly alter urinary nitrate excretion by iso- or allografts, suggesting that nitric oxide production is not a substrate-limited process in this model. Graft survival in this group was unchanged. L-NMMA produced a small increase in graft survival from 5.1 +/- 0.1 to 6.3 +/- 0.3 days compared with control allografts (P = 0.001) and abolished the rise in urinary nitrate excretion seen with control allografts. Lower doses of L-NMMA produced dose-related decrements in urinary nitrate excretion, but did not alter graft survival. We found that allograft rejection can proceed to graft loss despite complete inhibition of the increase in nitric oxide production that occurs during untreated rejection. The small increase in graft survival suggests that nitric oxide plays a minor role as a cytotoxic effector molecule in this model of acute rejection.

[Patterns of arteriovenous crossings in branch retinal vein occlusion]

The fundus color and fluorescein angiographic photographs of 82 eyes in 76 cases with recent branch retinal vein occlusion (BRVO) were compared with those of 82 eyes in 82 cases without BRVO in the age-sex-matched control group to determine the relationship between the arteriovenous crossing and BRVO. It was found that 90.3% of the crossings at the obstructive sites were located at the temporal quadrant, especially the superior temporal quadrant, and the artery lay anterior to the vein at the crossing in all of the eyes with BRVO (100%). In the 3 subgroups of the control group, the rates of the crossing at the obstructive site with the artery lying anterior to the vein were 67.1%, 70.0% and 74.4% in the B, C and D subgroups, respectively. Each of the rate of the 3 subgroups was compared with that of the BRVO group, statistically. There were significant differences (P < 0.001). The results suggest that a crossing with artery lying anterior to the vein possibly be one of the risk factors of BRVO and the artery exerting mechanical pressure upon the vein be the main cause in the pathogenesis of BRVO.

Three types of liver cell dysplasia (LCD) in small cirrhotic nodules are distinguishable by karyometry and PCNA labelling, and their features resemble distinct grades of hepatocellular carcinoma

We have studied the occurrence and specific features of liver cell dysplasia (LCD) in Chinese patients showing liver cirrhosis with or without hepatocellular carcinoma (HCC). Three types of LCD (SLCD, LLCDo, LLCDe) were morphologically defined, and these types were further analyzed using karyometry, estimation of nucleic acid content and density, and PCNA immunostaining. Features found for three types of LCD were compared with those of normal hepatocytes (NLC), simple regenerating hepatocytes (SRLC), and cells of HCCs covering different grades. The results show that 1) karyometry and nucleic acid parameters allow an objective separation of LCD types both from NLC and SRLC; 2) karyometric features of LLCDe are most close to those of highly differentiated HCCs, whereas nuclear size and chromatin composition of SLCD closely reflect those of poorly differentiated HCCs; 3) the frequency of LCD clusters was higher in cirrhotic livers carrying HCC, being about double for all three LCD types; 4) the highest PCNA labelling occurred in the small cell group of LCD (SLCD), still, however, being smaller than that of simple regenerating hepatocytes. Based on these findings it is suggested that, similar to atypical adenomatous hyperplasia, LCDs of distinct morphotypes may represent precursor lesions for HCC, and some cellular forms may mimick cell types known to occur in experimental carcinogenesis.

Effects of tetrandrine on production of leukotriene B4 and thromboxane B2 in rabbit blood

The effects of tetrandrine (Tet) on the production of 2 major metabolites of arachidonic acid (AA), the leukotriene B4 (LTB4) and the thromboxane B2 (TXB2) in rabbit whole blood were investigated by reversed phase high pressure liquid chromatography (HPLC) and radioimmunoassay (RIA), respectively. After incubation with different doses of Tet for 15 min in vitro, the production of LTB4 and TXB2 by rabbit whole blood stimulated with calcimycin (20 mumol.L-1) was inhibited in a dose-dependent manner, with IC50 value of 17.8 +/- 8.6 and 17.7 +/- 9.2 mumol.L-1, respectively. In the presence of exogenous AA, the inhibitory effects of Tet were markedly lessened. The effects of Tet were much like those of calmodulin (CaM) antagonist fluphenazine (Flu). Dexamethasone (Dex) also inhibited the production of LTB4 and TXB2 when incubated with rabbit whole blood for 60 min. Tet iv 10 mg.kg-1 also inhibited the production of LTB4 and TXB2 in rabbit whole blood stimulated with calcimycin. These results suggest that Tet may be an antagonist of CaM, thus suppressing the release of AA which was catalyzed by CaM dependent phospholipase A2 (PLA2) from the membrane phospholipids of blood cells.

Tolerance to glyceryl trinitrate in isolated human internal mammary arteries

The purpose of this study was to examine the vascular reactivity of segments of internal mammary artery removed from patients undergoing coronary artery bypass operations. Responses to relaxant and contractile agents were compared in arteries removed from patients who had or had not been treated with glyceryl trinitrate after admission to the hospital until operation. Segments of mammary artery were removed from 13 patients who underwent coronary artery bypass grafting. Endothelium-containing rings of artery, 3 to 5 mm long, were suspended in physiologic saline solution in 20 ml organ baths. Responses to the endothelium-dependent relaxant acetylcholine and the endothelium-independent relaxants glyceryl trinitrate and sodium nitroprusside were compared. In addition, contractile responses to phenylephrine and 9,11-dideoxy-9 alpha,11 alpha-methanoepoxy prostaglandin F2 alpha (U46619) were examined. Glyceryl trinitrate-induced relaxation was significantly impaired in mammary artery segments from patients treated with that nitrate before operation; the responses to acetylcholine and sodium nitroprusside were not affected. Previous treatment with glyceryl trinitrate also reduced the contractile responses to both phenylephrine and U46619. These studies indicate that treatment of patients with glyceryl trinitrate before operation induces significant tolerance to this agent in the mammary artery; however, there was no evidence of cross tolerance to sodium nitroprusside or the endothelium-dependent vasodilator acetylcholine. Glyceryl trinitrate may therefore not always be effective in dilating mammary artery grafts and sodium nitroprusside may be a more effective dilator of the internal mammary artery in patients who have been treated with glyceryl trinitrate before operation.

Inhibition of nitric oxide synthase specifically enhances adrenergic vasoconstriction in rabbits

1. The effect of inhibition of nitric oxide biosynthesis using N-nitro-L-arginine (NOLA) was examined in conscious rabbits and rabbit isolated aortae. 2. In autonomically blocked conscious rabbits intravenous infusion of NOLA (15 mg/kg) significantly increased arterial pressure and hindlimb vascular resistance but did not affect heart rate. Depressor and hindlimb vasodilator responses to acetylcholine (3-12 micrograms/kg per min) were significantly attenuated in the presence of NOLA. In contrast, NOLA significantly enhanced responses to intravenous infusion of glyceryl trinitrate (10-40 micrograms/kg per min) in vivo. 3. Infusion of noradrenaline (1-4 micrograms/kg per min) or the release of neuronal noradrenaline in response to the infusion of tyramine (80-320 micrograms/kg per min) increased arterial pressure and hindlimb vascular resistance in autonomically blocked conscious rabbits. After the administration of NOLA, the vasoconstrictor responses to both noradrenaline and tyramine were significantly enhanced. 4. In isolated rabbit aortae, NOLA (10 mumol/L) significantly impaired relaxant responses to acetylcholine but did not affect responses to glyceryl trinitrate. NOLA enhanced contractile responses to the adrenoceptor agonists noradrenaline and phenylephrine but did not affect the contractile responses to the thromboxane-mimetic U46619. 5. These data indicate that in autonomically blocked conscious rabbits, NOLA causes systemic vasoconstriction, impairs dilator responses to acetylcholine and enhances dilator responses to glyceryl trinitrate. In addition, NOLA enhances constrictor responses to both exogenous and neuronally-released noradrenaline. These results suggest that nitric oxide is important in the regulation of normal vascular tone and in the modulation of vascular responses to vasodilator and vasoconstrictor agents.

Baroreceptor reflexes and vascular reactivity during inhibition of nitric oxide synthesis in conscious rabbits

The effect of the nitric oxide (NO) synthase inhibitor N-nitro-L-arginine (NOLA) on vascular reactivity and the baroreceptor heart rate reflex was examined in chronically instrumented conscious rabbits. NOLA (15 mg/kg i.v.) significantly increased mean arterial pressure and hindlimb vascular resistance and decreased heart rate. Increases and decreases in arterial pressure were produced by the intravenous injection of phenylephrine and sodium nitroprusside respectively and the values obtained relating mean arterial blood pressure to heart rate were fitted to a sigmoid curve. NOLA significantly reduced the lower plateau of the arterial pressure--heart rate curve but did not significantly affect baroreceptor sensitivity. Depressor and hindlimb vasodilator responses to acetylcholine were significantly impaired by NOLA whereas responses to sodium nitroprusside were significantly enhanced. The pressor and hindlimb vasoconstrictor responses to phenylephrine were significantly enhanced in the presence of NOLA. We conclude that the bradycardia produced by NOLA does not result from a change in baroreceptor sensitivity. The continuous generation of NO appears to be important in regulating basal vascular resistance and in modulating vascular reactivity to both vasodilator and vasoconstrictor agents.

The effect of hypercholesterolaemia and atherosclerosis on α-adrenoceptor-mediated vasoconstriction in conscious rabbits and rabbit aorta

Rabbits were fed a diet containing 1% cholesterol for 4 or 8 weeks and the constrictor responses to alpha-adrenoceptor agonists, as well as endothelium-dependent and endothelium-independent dilatation, were examined both in vivo and in vitro. The high cholesterol diet caused a significant elevation of plasma cholesterol concentration but no macroscopic evidence of atherosclerosis after 4 weeks whereas after 8 weeks there was a significant development of atherosclerotic lesions in the thoracic and abdominal aorta. In conscious rabbits pressor responses to the non-selective alpha-adrenoceptor agonist noradrenaline and the selective alpha 1-adrenoceptor agonist phenylephrine were enhanced after 4 weeks but returned to control levels after 8 weeks on the diet. The pressor responses to the alpha 2-adrenoceptor agonist B-HT 920 were reduced by the development of atherosclerosis. In the isolated thoracic aorta from these rabbits contractile responses to noradrenaline were impaired by hypercholesterolaemia whereas responses to phenylephrine were unaffected. Endothelium-dependent relaxation was impaired by hypercholesterolaemia both in vivo and in vitro after 4 and 8 weeks on the diet whereas endothelium-independent relaxation was not affected. These results indicate that the effect of hypercholesterolaemia on alpha-adrenoceptor-mediated constriction is dependent on: (1) the absence or presence of atherosclerotic lesions, (2) the size of the artery and (3) the subtype of alpha-adrenoceptor involved in the response. There does not appear to be any relationship between the loss of endothelium-dependent relaxation in hypercholesterolaemia and the observed changes in adrenergic vasoconstriction.

Effect of tolerance to glyceryl trinitrate on vascular responses in conscious rabbits

1. The effect of tolerance to glyceryl trinitrate (GTN) on vasodilator and vasoconstrictor responses was examined in conscious rabbits and isolated rabbit aortic rings. 2. In conscious rabbits, depressor responses to 5 min infusions of GTN (10-40 micrograms/kg per min intravenously (i.v.)), sodium nitroprusside (SNP, 5-20 micrograms/kg per min i.v.) and acetylcholine (ACh, 3-12 micrograms/kg per min i.v.) were examined before and after transdermal treatment with GTN (20 mg/48 h). GTN pretreatment significantly attenuated GTN-induced depressor responses, indicating the development of tolerance, but did not affect the reductions in arterial pressure induced by SNP or ACh. 3. Similarly, aortic rings taken from GTN pretreated rabbits exhibited tolerance to GTN but the relaxant responses to SNP or the calcium ionophore A23187 were not affected. In the aortic rings from GTN-tolerant rabbits contractile responses to serotonin or the thromboxane-mimetic U46619 were significantly attenuated, in contrast to the responses to the alpha 1-adrenoceptor agonist phenylephrine (PE) which were significantly enhanced. 4. Similarly, in conscious rabbits, PE-induced increases in arterial pressure and hindlimb vascular resistance were significantly enhanced by GTN pretreatment but the responses to the alpha 2-adrenoceptor agonist BHT 920 were unaffected. 5. In conclusion, tolerance to GTN does not affect endothelium-dependent vasodilatation but does cause a selective enhancement of alpha 1- but not alpha 2-adrenoceptor-mediated vasoconstriction.

Haemodynamic responses to N-nitro-L-arginine in conscious rabbits

1. The effect of N-nitro-L-arginine (NOLA) on mean arterial pressure (AP), hindlimb vascular resistance (HVR) and heart rate (HR) was examined in conscious rabbits. 2. NOLA (15 mg kg, i.v.) increased AP (delta AP = 14 +/- 3 mmHg) and HVR (delta HVR = 0.8 +/- 0.3 U) and decreased HR (delta HR = -66 +/- 8 beats/min). AP remained elevated for at least 2 h following NOLA infusion but had returned to control levels after 24 h. In contrast, the hindlimb vaso-constriction and bradycardia were sustained for at least 48 h but had returned to control levels after 72 h. 3. In the presence of total autonomic blockade (hexamethonium 30 mg/kg; propranolol 1 mg/kg and atropine 0.1 mg/kg) NOLA continued to have a pressor (delta AP = 33 +/- 9 mm Hg) and hindlimb vasoconstrictor action (delta HVR = 0.4 +/- 0.1 U) but did not affect HR (delta HR = -1 +/- 3 beats/min). 4. NOLA has a prolonged pressor and vasoconstrictor action which is independent of any action in the central nervous system and which results in a marked reflex bradycardia. These results suggest that the peripheral biosynthesis of nitric oxide is important in regulation vascular tone and arterial pressure.

HDV (delta factor) infection complicated with subacute fulminant hepatitis B. A morphological and immunohistochemical observation

In 75 patients with subacute fulminant hepatitis B (SAFH), HDAg positive liver cells were observed in 14 cases (18.67%) by direct enzyme labelled method. It was found further that HDV (delta factor) infection was an important cause in producing massive necrosis of liver cells and superinfection of HDV with hepatitis B was identified as one of the causes of SAFH. This experiment also showed that the number of HDAg positive cells was in direct proportion to the area of liver necrosis. No obvious lymphocytic infiltrations and cytotoxic phenomena around the necrotic foci and HDAg positive cells could be found, while the cytoplasmic type HDAg positive cells showed distinct degeneration or even atrophy. Hence it was suggested that HDV could be a direct pathogenesis. No obvious characteristic changes in morphology of HDV infection could be found.

On the mechanism of sulfite activation of chloroplast thylakoid ATPase and the relation of ADP tightly bound at a catalytic site to the binding change mechanism

Washed chloroplast thylakoid membranes upon exposure to [3H]ADP retain a tightly bound [3H]ADP on a catalytic site of the ATP synthase. The presence of sufficient endogenous or added Mg2+ results in an enzyme with essentially no ATPase activity. Sulfite activates the ATPase, and many molecules of ATP per synthase can be hydrolyzed before most of the bound [3H]ADP is released, a result interpreted as indicating that the ADP is not bound at a site participating in catalysis by the sulfite-activated enzyme [Larson, E. M., Umbach, A., & Jagendorf, A. T. (1989) Biochim. Biophys. Acta 973, 75-85]. We present evidence that this is not the case. The Mg2(+)- and ADP-inhibited enzyme when exposed to MgATP and 20-100 mM sulfite shows a lag of about 1 min at 22 degrees C and of about 15 s at 37 degrees C before reaching the same steady-state rate as attained with light-activated ATPase that has not been inhibited by Mg2+ and ADP. The lag is not eliminated if the enzyme is exposed to sulfite prior to MgATP addition, indicating that ATPase turnover is necessary for the activation. The release of most of the bound [3H]ADP parallels the onset of ATPase activity, although some [3H]ADP is not released even with prolonged catalytic turnover and may be on poorly active or inactive enzyme or at noncatalytic sites. The results are consistent with most of the tightly bound [3H]ADP being at a catalytic site and being replaced as this Mg2(+)- and ADP-inhibited site regains equivalent participation with other catalytic sites on the activated enzyme.(ABSTRACT TRUNCATED AT 250 WORDS)

Relationship of tightly bound ADP and ATP to control and catalysis by chloroplast ATP synthase

Whether the tightly bound ADP that can cause a pronounced inhibition of ATP hydrolysis by the chloroplast ATP synthase and F1 ATPase (CF1) is bound at catalytic sites or at noncatalytic regulatory sites or both has been uncertain. We have used photolabeling by 2-azido-ATP and 2-azido-ADP to ascertain the location, with Mg2+ activation, of tightly bound ADP (a) that inhibits the hydrolysis of ATP by chloroplast ATP synthase, (b) that can result in an inhibited form of CF1 that slowly regains activity during ATP hydrolysis, and (c) that arises when low concentrations of ADP markedly inhibit the hydrolysis of GTP by CF1. The data show that in all instances the inhibition is associated with ADP binding without inorganic phosphate (Pi) at catalytic sites. After photophosphorylation of ADP or 2-azido-ADP with [32P]Pi, similar amounts of the corresponding triphosphates are present on washed thylakoid membranes. Trials with appropriately labeled substrates show that a small portion of the tightly bound 2-azido-ATP gives rise to covalent labeling with an ATP moiety at noncatalytic sites but that most of the bound 2-azido-ATP gives rise to covalent labeling by an ADP moiety at a catalytic site. We also report the occurrence of a 1-2-min delay in the onset of the Mg2+-induced inhibition after addition of CF1 to solutions containing Mg2+ and ATP, and that this delay is not associated with the filling of noncatalytic sites. A rapid burst of Pi formation is followed by a much lower, constant steady-state rate.(ABSTRACT TRUNCATED AT 250 WORDS)