Relationship between endothelial dysfunction, oxidant stress and aspirin resistance in patients with stable coronary heart disease

OBJECTIVE

Interindividual variability of platelet inhibition after aspirin administration has been described. Additionally, aspirin resistance occurs in some individuals, but the mechanism for aspirin resistance is still unknown. The aim of the present study was to examine the role of endothelial dysfunction in aspirin resistance.

METHODS

The antiplatelet effect of aspirin was studied prospectively in 54 consecutive patients with stable coronary heart disease. Platelet aggregation rate was measured and aspirin resistance was defined by a relative inhibition of adenosine diphosphate (5 micromol/L)-induced platelet aggregation of >or=70%. Thrombomodulin (TM) and free tissue factor pathway inhibitor (TFPI) were measured as endothelial dysfunction markers. Erythrocyte superoxide dismutase activity, plasma level of vitamin C, vitamin E and lipoperoxide were measured to estimate the oxidative stress.

RESULTS

Platelet aggregation was positively correlated with TM (r = 0.277, P < 0.05) and TFPI (r = 0.288, P < 0.05) respectively. The TFPI level in aspirin-resistant patients (119.5 +/- 13.5 ng/mL) was significantly higher than that in aspirin-sensitive patients (107.8 +/- 18.9 ng/mL; P < 0.05). There were no statistically significant differences on any indicator of oxidative stress between two groups.

CONCLUSIONS

Endothelial dysfunction is one of the mechanisms for aspirin resistance, whereas oxidative stress may not involve in the process of aspirin resistance.

Stat3 activation in human endometrial and cervical cancers

The activation of signal transducer and activator of transcription 3 (Stat3) has been implicated in the oncogenesis of cancer and is regarded as a novel target for cancer therapy. Stat3 is classified as a proto-oncogene, because an activated form of Stat3 can mediate oncogenic transformation in cultured cells and tumour formation in nude mice. The constitutive activation of Stat3 has been frequently detected in various types of human cancers. However, the constitutive activation of Stat3 in endometrial and cervical cancers has not been studied. We examined tyrosine phosphorylation of Stat3 (activated form of Stat3) in multiple endometrial and cervical cancer tissues using tissue microarray slides as well as cancer cell lines to explore the possible activation of Stat3. Our results indicated that elevated phosphorylation of Stat3 was detected in cervical and endometrial cancer cell lines. Our results also showed that elevated levels of phosphorylation of Stat3 protein were detected in the endometrial and cervical cancer specimens. This is the first study to demonstrate that Stat3 is activated in human endometrial and cervical cancer tissues. Immunohistochemical staining showed that activated Stat3 is associated with increased expression of downstream antiapoptotic genes, Bcl-xL, survivin, and Mcl-1 in these tissues. Expression of a dominant-negative Stat3 mutant using adenovirus-mediated gene transfer inhibited cell growth and induced apoptosis in HeLa and SiHa cervical cancer cell lines expressing elevated levels of Stat3 phosphorylation. Further, a JAK/Stat3 small molecular inhibitor, JSI-124, induced apoptosis more selectively in HeLa and SiHa cancer cell lines than Ishikawa cell line without elevated levels of Stat3 phosphorylation. These results indicate that Stat3 is activated in human endometrial and cervical cancers and the inhibition of constitutive Stat3 signaling may be an effective target for cancer intervention in these two cancers.

Behavioral, neurochemical and neuroendocrine effects of the ethanolic extract from Curcuma longa L. in the mouse forced swimming test

Curcuma longa L. (turmeric) has been used for centuries in traditional Chinese medicine as a treatment for mental disorders including depression. The studies described here were undertaken to determine the behavioral, neurochemical and neuroendocrine effects of the ethanolic extract from Curcuma longa using the forced swimming test (FST) in male ICR strain of mice. The ethanolic extract was found to reduce the duration of immobility in the mouse FST when orally administered for 21 days. The extract markedly attenuated swim stress-induced decreases in serotonin, 5-hydroxyindoleacetic acid, noradrenaline and dopamine concentrations, as well as increases in serotonin turnover. Furthermore, the ethanolic extract of Curcuma longa significantly reversed the swim stress-induced increases in serum corticotropin-releasing factor and cortisol levels. Under these conditions, the ethanolic extract of Curcuma longa was partly different from fluoxetine and amitriptyline. These results suggested that antidepressant properties of the ethanolic extract of Curcuma longa was mediated through regulations of neurochemical and neuroendocrine systems and it may be a useful agent against depression.

Development of an effective sample preparation approach for proteomic analysis of silkworm eggs using two-dimensional gel electrophoresis and mass spectrometry

Sample preparation is still the first and important step toward successful two-dimensional gel electrophoresis (2DE) and identification in proteomics study. The 2DE profiling of eggs of silkworm species by using conventional one-step extraction, however, is unsatisfactory because high-abundance proteins such as egg-specific protein (ESP) and No 30 family (30 KP) in the extract lead to difficulties in detecting most of biologically relevant proteins. Based on the tendency of these abundant proteins to be soluble in Tris-HCl buffer, we report herein a robust approach in which the extract enriched in ESP and 30 KP was fractionationed and mixed with the re-extract of residual pellet in an optimal proportion. In comparison with the one-step method, the 2DE pattern was improved by this new method with over one-third enhancement in spots. A total of 48 unique proteins obtained have been furthermore identified by mass spectrometry (MS) and MS/MS. The identified proteins are found to include heat shock proteins families, ribosomal proteins, disulfide isomerase proteins, Glutathione S-transferase, and elongation factor, etc., which are mainly involved in some important processes. To our knowledge, this is the first time that the several proteins have been detected in silkworm eggs by proteomics means. This simple and reproducible approach would raise the opportunity of discovering and identifying more biomarkers and determining their possible roles in further studies.

Factors affecting delays in tuberculosis diagnosis in rural China: a case study in four counties in Shandong Province

Improving case detection is an urgent and serious challenge for tuberculosis (TB) control in China. We investigated the extent to which TB patients delayed seeking TB care and health services delayed reaching a diagnosis, and socio-economic factors associated with the delays. Standard questionnaires were administered to 190 new smear-positive TB patients who had completed treatment at TB dispensaries in four counties of Shandong Province in 2001. Multivariate analysis using Cox Regression showed that old age, lack of education and distance from home to a township health centre were significantly associated with delay in seeking care from service providers. In examining the delay between first contact with a service provider and diagnosis, we found that women experienced longer delays than men, and that the higher the level of facility patients first visited, the less time was needed to achieve a diagnosis. These two factors were statistically significant in multivariate Cox Regression analysis. We concluded that the elderly, the less educated, women, and those living far from health facilities face the longest delays in reaching TB services and achieving diagnosis.

Is INR between 2.0 and 3.0 the optimal level for Chinese patients on warfarin therapy for moderate-intensity anticoagulation?

AIM

To examine the optimal range of International Normalized Ratio (INR) for Chinese patients receiving warfarin for moderate-intensity anticoagulation.

METHODS

This was a retrospective cohort study conducted at the ambulatory setting of a 1400-bed public teaching hospital in Hong Kong. The INR measurements and occurrence of serious or life-threatening haemorrhagic and thromboembolic events among patients newly started on warfarin from 1 January 1999 to 30 June 2001 for indications with target INR 2-3 were analysed. The INR-specific incidence of bleeding and thromboembolism were calculated.

RESULTS

A total of 491 patients were included, contributing to 453 patient-years of observation period. Forty-seven of the 491 patients experienced 25 haemorrhagic events (5.5 per 100 patient-years) and 27 thromboembolic events (6.0 per 100 patient-years). The percentage of patient-time spent within therapeutic INR range (2-3), INR <2 and INR >3 were 50, 44 and 6%, respectively. The incidence of either haemorrhagic or thromboembolic events was lowest (< or =4 events per 100 patient-years) at INR values between 1.8 and 2.4.

CONCLUSIONS

An INR of 1.8-2.4 appeared to be associated with the lowest incidence rate of major bleeding or thromboembolic events in a cohort of Hong Kong Chinese patients receiving warfarin therapy for moderate-intensity anticoagulation.

Sonographic pitfalls in the diagnosis of enteric duplication cysts

OBJECTIVE

The sonographic double wall sign has been well described in the literature and is often the cornerstone in suggesting the diagnosis of an enteric duplication cyst. We report two cases with this sign that were erroneously diagnosed as enteric cysts and a third case without this sonographic feature that proved to be a duplication cyst. Histologic analysis of the specimens helps explain the cause of the sonographic pitfalls.

CONCLUSION

The potential sonographic visualization of the split hypoechoic muscularis propria layer or identification of all five layers will increase the specificity in making the sonographic diagnosis of duplication cyst.

Cl- channels are expressed in human normal monocytes: a functional role in migration, adhesion and volume change

Increased adhesion and diapedesis of monocytes appear to be primary initiating factors in the pathophysiology of occlusive vascular diseases, including atherosclerosis and restenosis. However, the underlying mechanisms of transendothelial migration and invasion of monocytes into the blood vessels are not known. Alterations in ion channels on the cell membrane are generally involved in induced changes in shape and volume. In the present study, we investigated the expression and functional role of chloride channels in freshly isolated human blood monocytes. The Cl- currents in whole-cells were measured by the patch-clamp technique. We observed whole cell Cl- currents, which were time-independent and outwardly rectifying. The chloride channel blockers 5-nitro-2-(3-phenylpropylamino) benzoic acid (NPPB) and R(+)-[(6,7-dichloro-2-cyclopentyl-2,3-dihydro-2-methyl-1-oxo-1H-inden-5yl)-oxy]acetic acid 94 (IAA94) attenuated the Cl- currents. NPPB and IAA94 also inhibited chemotaxis of monocytes, as measured in Boyden chemotactic chambers, with the same sensitivity. NPPB but not IAA94, increased the cell volume as measured by shape change, and decreased tumour necrosis factor (TNF)-alpha-induced monocyte adhesion to endothelial cells. These results suggest that monocytes contain Cl- channels which regulate transendothelial migration of monocytes, due presumably to an alteration in cell volume.

Use of convalescent plasma therapy in SARS patients in Hong Kong

In order to evaluate the efficacy of convalescent plasma therapy in the treatment of patients with severe acute respiratory syndrome (SARS), 80 SARS patients were given convalescent plasma at Prince of Wales Hospital, Hong Kong, between 20 March and 26 May 2003. Good outcome was defined as discharge by day 22 following the onset of SARS symptoms. Poor outcome was defined as death or hospitalization beyond 22 days. A higher day-22 discharge rate was observed among patients who were given convalescent plasma before day 14 of illness (58.3% vs 15.6%; P<0.001) and among those who were PCR positive and seronegative for coronavirus at the time of plasma infusion (66.7% vs 20%; P=0.001).

Retrospective comparison of convalescent plasma with continuing high-dose methylprednisolone treatment in SARS patients

Treatment of severe acute respiratory syndrome (SARS) is experimental, and the effectiveness of ribavirin–steroid therapy is unclear. Forty SARS patients with progressive disease after ribavirin treatment and 1.5 g of pulsed methylprednisolone were given either convalescent plasma (n = 19) or further pulsed methylprednisolone (n = 21) in a retrospective non‐randomised study. Good clinical outcome was defined as discharge by day 22 following the onset of symptoms. Convalescent plasma was obtained from recovered patients after informed consent. Patients in the plasma group had a shorter hospital stay (p 0.001) and lower mortality (p 0.049) than the comparator group. No immediate adverse effects were observed following plasma infusion.

Use of fasting urinary methylmalonic acid to screen for metabolic vitamin B12 deficiency in older persons

OBJECTIVES

We sought to determine the cutoffs of fasting urinary methylmalonic acid (MMA) indicating elevated and mildly elevated serum MMA concentrations in older persons.

METHODS

We studied 113 female Chinese vegetarians older than 55 y with normal renal function. Fasting serum samples were obtained for measurement of vitamin B12, MMA, and folate and tests of renal function. A fasting urine sample was collected for MMA measurement by the stable-isotope dilution method. The correlation between serum and urinary MMA levels was examined. The optimal cutoffs of urinary MMA for predicting elevated and mildly elevated serum MMA were estimated by use of receiver operating characteristic curves.

RESULTS

Fasting urinary and serum MMA levels were linearly correlated. Pearson's correlation coefficient was 0.94. The cutoff of fasting urinary MMA of 2 microM/mM of creatinine had a sensitivity of 79%, a specificity of 85%, and a positive predictive value of 93% for elevated serum MMA (> 0.4 microM/L). A cutoff of 1.5 microM/mM of creatinine had a sensitivity of 86%, a specificity of 85%, and a positive predictive value of 95% for mildly elevated serum MMA (> 0.3 microM/L). Both cutoffs had high positive predictive values for subnormal vitamin B12 concentrations.

CONCLUSION

Overnight fasting urinary MMA concentrations have a strong linear relation to serum MMA in older vegetarians without renal impairment. Urinary MMA is potentially useful as a screening tool for metabolic vitamin B12 deficiency in older persons.

The expression of oestrogen receptor (ER)-beta and its variants, but not ERalpha, in adult human mammary fibroblasts

Whilst oestrogen receptor (ER)-alpha and ERbeta have been shown to be important in the development of the mammary gland, the cell-specific expression pattern of these two receptors within the human breast is not clear. Although it is well established that in the developing rodent mammary gland stromal ERalpha mediates the secretion of growth factors which stimulate the proliferation of the ductal epithelium, the expression of ERalpha in human adult breast stromal fibroblasts is controversial, and the expression of ERbeta has not been properly defined. In the present study, we have evaluated the expression of ERalpha and ERbeta by immunohistochemistry in normal tissue samples, and in purified human breast fibroblasts by Western blotting, RT-PCR analysis and ligand-binding sucrose gradient assay. Our data clearly demonstrated that ERbeta variants, including ERbeta1, ERbeta2, ERbeta5, ERbetadelta and ERbetains, but not ERalpha, are expressed in human adult mammary fibroblasts. These results are supported by the findings that an ERbeta-selective ligand, BAG, but not the ERalpha high-affinity ligand oestradiol, can induce fibroblast growth factor-7 release and activate transcription from an oestrogen-responsive element promoter in these adult human mammary fibroblasts. Together, these observations revealed that, in the adult breast and in breast cancer, the proliferative signals derived from the stroma of adult mammary glands in response to oestrogen are not mediated by ERalpha and provide new insights into the nature of stromal-epithelial interactions in the adult mammary gland. In addition, the expression of these ERbeta variants in cells where there is no ERalpha suggested that these ERbeta splice forms may have functions other than that of modulating ERalpha activity.

Antiproliferative activity of the extract of Gleditsia sinensis fruit on human solid tumour cell lines

BACKGROUND

The fruit extract of Gleditsia sinensis Lam. (GSE) is a traditional herbal medicine that is saponin-rich. However, its activity on solid tumour cell lines has never been demonstrated.

METHODS

The activity of GSE was demonstrated in four cancer cell lines (breast cancer MCF-7, MDA-MB231, hepatoblastoma HepG2 and oesophageal squamous carcinoma cell line SLMT-1) using MTT assay, anchorage-independent clonogenicity assay, DNA laddering and in situ cell death detection.

RESULTS

The mean MTT(50) (the mean concentration of GSE to reduce MTT activity by 50%) ranged from 16 to 20 microg/ml of GSE. An anchorage-independent clonogenicity assay showed that all of the four solid tumour cell lines gradually lost their regeneration potential after treatment with GSE, DNA fragmentation and TUNEL analysis demonstrated that the action of GSE is both dose- and time course-dependent.

CONCLUSIONS

Our results suggest that GSE has a cytotoxic activity and can induce apoptosis in human solid tumour cell lines.

The art of war: Innate and adaptive immune responses

Research over the last several years has greatly advanced our understanding of the mechanisms by which the immune system functions. There exist two main branches of immunity, termed innate and adaptive immunity. Innate immunity uses the genetic memory of germline-encoded receptors to recognize the molecular patterns of common pathogens. Adaptive immunity, akin to somatic memory, is a complex system by which the body learns to recognize a pathogen's unique antigens and builds an antigen specific response to destroy it. The effective development of the overall immune response depends on careful interplay and regulation between innate and adaptive immunity. Here we review our current understanding of how these integrated systems distinguish targets against which a response is appropriate and neutralize potentially pathogenic challenges.

Gene therapy to target dendritic cells from blood to lymph nodes

Peripheral lymph nodes (PLN) are strategic microenvironments where antigen-presenting dendritic cells (DC), loaded with environmental antigens, and naive lymphocytes meet to initiate immune responses. The unique capacity of DC to induce primary immune responses has led to their use in clinical medicine; however, delivering DC to lymph nodes is problematic. Intravenously injected DC cannot access to PLN, while DC injected into tissue migrate inefficiently through lymphatics to PLN. We achieved DC targeting to T-cell areas of PLN by endowing DC with a novel receptor for peripheral node addressin (PNAd), an adhesion molecule present on the lymph node venular endothelium. This novel receptor is a chimeric E/L-selectin (ELS) that, we have previously shown, binds to PNAd. DC were genetically modified by retroviral transduction to express ELS. ELS expression was targeted to tips of microvilli, and mediated rolling of DC on PNAd both in vivo and in vitro. Such genetically engineered DC could extravasate directly from blood through the lymph node endothelium as opposed to nontransduced DC. This study provides evidence that the trafficking of DC can be modified using gene transfer technologies. More efficient delivery of DC to PLN should assist the development of improved vaccination strategies.

Renormalization group theory for perturbed evolution equations

We show that proto-RG (renormaliation group) theory can be used to give a systematic description of the evolution of soltion of perturbed equations. The equations describing the deformation of its shape as the effect of perturbation are proto-RG equations. The RG approach may be simpler than inverse scattering theory (IST) and another approaches, because it dose not rely on any knowledge of IST. It is very concise and easy to understand.

[Clinical significance of Q-Tc dispersion after exercise in aged patients with old myocardial infarction]

OBJECTIVE

This study was aimed to evaluate clinical significance of Q-Tc dispersion after exercise in aged patients with old myocardial infarction.

METHOD

Sixty-four aged patients with old myocardial infarction(infarction group) were examined by treadmill exercise, dynamic electrocardiography, echocardiography, and were followed up for average of 24.12 +/- 7.7 months. 30 healthy aged persons were served as control group.

RESULTS

Compared with that (40.21 +/- 15.21 ms) before exercise, Q-Tc dispersion (59.37 +/- 20.17 ms) was increased significantly after exercise in infarction group(P < 0.01). But no significant difference was found in Q-Tc dispersion of control group before and after exercise(34.70 +/- 12.29 ms vs 38.91 +/- 13.62 ms P > 0.05). In infarction group, occurrence of abnormal contraction of left ventricular wall, aneurysms, NYHA III class and > III class of Lown's ventricular arrhythmia classification was significantly higher in Q-Tcd > 50 ms patients than that in Q-Tcd < 50 ms ones(P < 0.05). It was found that 5 patients died of cardiac sudden death in Q-Tcd > 50 ms patients and no one died of cardiac sudden death in Q-Tcd < 50 ms ones.

CONCLUSION

The Q-Tc dispersion after exercise is an important index to predict ventricular arrhythmia and cardiac death in the patients with old myocardial infarction.