Aspirin plus clopidogrel as secondary prevention after stroke or transient ischemic attack: a systematic review and meta-analysis

BACKGROUND

Antiplatelet agents are the mainstay for secondary prevention of non-cardioembolic stroke. This systematic review examined the safety and efficacy of short-, middle-, and long-term aspirin in combination with clopidogrel as secondary prevention of stroke or transient ischemic attack (TIA) of presumed arterial origin.

METHODS

PubMed, EmBase, and CENTRAL were searched up to May 2014. Randomized controlled trials (RCTs) that compared aspirin plus clopidogrel versus aspirin or clopidogrel as secondary prevention of stroke or TIA of arterial origin were included. The analyses were stratified into short-term (≤3 months), middle-term (>3 months and <1 year), and long-term (≥1 year). Outcomes were compared using risk ratio (RR) and 95% confidence interval (95% CI).

RESULTS

Eight RCTs (20,728 patients) were included in the overall analysis. Compared with aspirin or clopidogrel alone, the complete analysis of all the data indicated that the combination therapy significantly reduced the risk of stroke recurrence (RR, 0.82; 95% CI 0.70-0.96, p = 0.01) and major vascular events (RR, 0.84; 95% CI 0.73-0.96, p < 0.01). But the risk of hemorrhagic stroke (RR, 1.59; 95% CI 1.08-2.33, p = 0.02) and major bleeding (RR, 1.83; 95% CI 1.37-2.45, p < 0.01) was increased. No RCT studied middle-term combination therapy. The analyses were therefore stratified into only two subgroups, short- and long-term treatment. Stratified analysis of short-term treatment showed that relative to monotherapy, the drug combination reduced the risk of stroke recurrence (RR, 0.69; 95% CI 0.59-0.81, p < 0.01) and did not increase the risk of hemorrhagic stroke (RR, 1.23; 95% CI 0.50-3.04, p = 0.65) and major bleeding events (RR, 2.17; 95% CI 0.18-25.71, p = 0.54). Short-term combination therapy was associated with a significantly lower risk of major vascular events (RR, 0.70; 95% CI 0.69 to 0.82, p < 0.01). Stratified analysis of long-term treatment revealed that the combination treatment did not decrease the risk of stroke recurrence (RR, 0.92; 95% CI 0.83-1.03, p = 0.15), but was associated with a significantly higher risk of hemorrhagic stroke (RR, 1.67; 95% CI 1.10-2.56, p = 0.02) and major bleeding events (RR, 1.90; 95% CI 1.46-2.48, p < 0.01). Long-term combination therapy failed to reduce the risk of major vascular events (RR, 0.92; 95% CI 0.84-1.03, p = 0.09).

CONCLUSIONS

Compared with monotherapy, short-term aspirin in combination with clopidogrel is more effective as secondary prevention of stroke or TIA without increasing the risk of hemorrhagic stroke and major bleeding events. Long-term combination therapy does not reduce the risk of stroke recurrence, and is associated with increased major bleeding events. The clinical applicability of the findings of this systematic review, however, needs to be confirmed in future clinical trials.

Flower color patterning in pansy (Viola × wittrockiana Gams.) is caused by the differential expression of three genes from the anthocyanin pathway in acyanic and cyanic flower areas

The petals of pansy (Viola × wittrockiana Gams.) 'Mengdie' exhibit a cyanic blotched pigmentation pattern. The accumulation of anthocyanins, cyanidin and delphinidin, was detected in the upper epidermal cells of the cyanic blotches. In order to elucidate the mechanism by which cyanic blotches are formed in pansy petal, the expression level of genes involved in anthocyanin synthesis was measured and compared between cyanic blotches and acyanic areas of the flower. The use of primers in conserved regions allowed the successful isolation of six cDNA clones encoding putative anthocyanin enzymes from pansy petals. The clones isolated encoded chalcone synthase (CHS), chalcone isomerase (CHI), flavanone 3-hydroxylase (F3H), flavonoid 3'-hydroxylase (F3'H), dihydroflavonol 4-reductase (DFR) and anthocyanidin synthase (ANS). The transcription patterns of seven genes (VwCHS, VwCHI, VwF3H, VwF3'H, VwDFR, VwF3'5'H, and VwANS) in cyanic blotches and acyanic areas of the petals at seven stages of flower development were determined by real-time quantitative PCR. Transcription of VwF3'5'H, VwDFR and VwANS was significantly increased in cyanic blotches at stages III-V of flower development, implicating these genes in the pigmentation of Viola × wittrockiana Gams. petals.

Abstract 2707: In vitro and in vivo evaluation of SNG1153, a synthetic modulator of ER-α36

Background: ER-α36, a novel truncated variant of estrogen receptor α, was recently discovered and extensively studied as a potential therapeutic target. ER-α36 was found to be overexpressed in many cancers including estrogen-positive and negative breast cancer, lung cancer, prostate cancer, endometrial cancer, liver cancer and other cancers. This suggests that ER-α36 is potentially a promising target for the development of novel anticancer agents with broader clinical applications. This study aims to evaluate the in vitro and in vivo performance of SNG1153, an orally available, synthetic modulator of ER-α36. Methods: the viabilities of ER-α36 overexpressed cancer cells were evaluated using a CCK-8 assay after exposure to SNG1153. Pharmacokinetic study was conducted in rat and SNG1153 was administered orally in escalated doses. In-vivo efficacies of SNG1153 were evaluated in Bcap-37 xenograft model, Ishikawa xenograft model and SPC-A-1 xenograft model. Results: SNG1153 showed significant inhibition at low micromolar concentrations in ER-α36 overexpressed cell lines including the one resistant to tamoxifen. SNG1153 exhibited a linear PK profile with a bioavailability of more than 55% in the rat PK study. In the in-vivo efficacy studies, 3 doses were investigated and SNG1153 showed dose-dependent inhibition. The tumor growth inhibition at high dose was 57% in the breast cancer Bcap-37 xenograft model, 65% in the endometrial cancer Ishikawa xenograft model and 52% in lung adenocarcinoma SPC-A-1 xenograft model. No signs of toxicity were observed in these models. Conclusion: SNG1153, as a synthetic ER-α36 modulator, showed promising activities in many in vitro and in vivo models. It is currently in preclinical development stage.

Citation Format: Bo Zhang, Kun Meng, Xiao Shang, Zhaoyi Wang, Yanzhong Zhang, Fang Fang, Jing Wang, Zonghui Wang, Jun Wang, Yuming Guo, Shiyang Liu, Feng Chen, Hongxia Ding, Jiancun Zhang, Jun Bao. In vitro and in vivo evaluation of SNG1153, a synthetic modulator of ER-α36. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 2707. doi:10.1158/1538-7445.AM2014-2707

Changes in hematological parameters in α-thalassemia individuals co-inherited with erythroid Krüppel-like factor mutations

Phenotypic variations in α-thalassemia mainly depend on the defective α-globin gene number. Genetic modifiers of the phenotype of Hemoglobin H (HbH) disease were poorly reported, apart from β-thalassemia allele that was identified ameliorating the severity of α-thalassemia. Because erythroid Krüppel-like factor (KLF1) mutations can modulate the red blood phenotype, we evaluated its effect on the α-thalassemia phenotype. Overall, we identified 72 subjects with five different KLF1 heterozygous mutations in 1468 individuals, including 65 out of 432 α-thalassemia carriers with fetal hemoglobin (HbF) levels ≥1%, 0 out of 310 carriers with HbF levels <1% and 7 out of 726 HbH disease patients. We firstly established the link between KLF1 mutations and relatively elevated hemoglobin A2 (HbA2 ) and HbF levels, along with lower mean corpuscular volume (MCV) and mean corpuscular hemoglobin (MCH) values in a group of α-thalassemia carriers. However, we concluded that KLF1 mutations were not significantly linked to HbH disease severity. On the basis of HBA or HBB genotype and gender, clinical severity of patients with HbH disease was correctly predicted in 73.3% cases. It may improve the screening and diagnostic assessment of α-thalassemia.

Controllable Self-organization of Polyphenylene Oxide Honeycomb Microstructure

Polymer films with patterned microstructure have been widely applied in various industrial areas such as micro reactors, chemical sensors and micro-molded template etc. In this paper, a self-supporting polymer film with regular honeycomb microstructure is fabricated by self-organization via evaporation of polyphenylene oxide (PPO) solution in which carbon disulfide is used as solvent under humid ambience. Apart from investigation of self-organization mechanism of PPO honeycomb including nucleation, growth of water droplets condensed upon liquid supporting substrate, the quantitative relationship between honeycomb microstructure and ambient conditions is built through tremendous self-organization experiments. The controllable formation of honeycomb microstructure with desirable hydrophobicity was achieved by use of built quantitative relationship. Moreover, hydrophobicity mathematical model of self-organized honeycomb thin film was proposed, and its validation was experimentally verified.

Hypothermia protects against oxygen-glucose deprivation-induced neuronal injury by down-regulating the reverse transport of glutamate by astrocytes as mediated by neurons

Glutamate is the major mediator of excitotoxic neuronal death following cerebral ischemia. Under severe ischemic conditions, glutamate transporters can functionally reverse to release glutamate, thereby inducing further neuronal injury. Hypothermia has been shown to protect neurons from brain ischemia. However, the mechanism(s) involved remain unclear. Therefore, the aim of this study was to investigate the mechanism(s) mediating glutamate release during brain ischemia-reperfusion injury under hypothermic conditions. Neuron/astrocyte co-cultures were exposed to oxygen-glucose deprivation (OGD) at various temperatures for 2h, and cell viability was assayed 12h after reoxygenation. PI and MAP-2 staining demonstrated that hypothermia significantly decreased neuronal injury. Furthermore, [(3)H]-glutamate uptake assays showed that hypothermia protected rat primary cortical cultures against OGD reoxygenation-induced injury. Protein levels of the astrocytic glutamate transporter, GLT-1, which is primarily responsible for the clearance of extracellular glutamate, were also found to be reduced in a temperature-dependent manner. In contrast, expression of GLT-1 in astrocyte-enriched cultures was found to significantly increase following the addition of neuron-conditioned medium maintained at 37 °C, and to a lesser extent with neuron-conditioned medium at 33 °C. In conclusion, the neuroprotective effects of hypothermia against brain ischemia-reperfusion injury involve down-regulation of astrocytic GLT-1, which mediates the reverse transport of glutamate. Moreover, this process may be regulated by molecules secreted by stressed neurons.

Childhood sexual abuse and the risk for recurrent major depression in Chinese women

BACKGROUND

Studies in Western countries have repeatedly shown that women with a history of childhood sexual abuse (CSA) are at increased risk for developing major depression (MD). Would this relationship be found in China?

METHOD

Three levels of CSA (non-genital, genital, and intercourse) were assessed by self-report in two groups of Han Chinese women: 1970 clinically ascertained with recurrent MD and 2597 matched controls. Diagnostic and other risk factor information was assessed at personal interview. Odds ratios (ORs) were calculated by logistic regression and regression coefficients by linear or Poisson regression.

RESULTS

Any form of CSA was significantly associated with recurrent MD [OR 3.26, 95% confidence interval (CI) 1.95-5.45]. This association strengthened with increasing CSA severity: non-genital (OR 2.47, 95% CI 1.17-5.23), genital (OR 2.77, 95% CI 1.32-5.83) and intercourse (OR 13.35, 95% CI 1.83-97.42). The association between any form of CSA and MD remained significant after accounting for parental history of depression, childhood emotional neglect (CEN), childhood physical abuse (CPA) and parent-child relationship. Among the depressed women, those with CSA had an earlier age of onset, longer depressive episodes and an increased risk for generalized anxiety disorder (GAD; OR 1.92, 95% CI 1.39-2.66) and dysthymia (OR 2.16, 95% CI 1.52-3.09).

CONCLUSIONS

In Chinese women CSA is strongly associated with MD and this association increases with greater severity of CSA. Depressed women with CSA have an earlier age of onset, longer depressive episodes and increased co-morbidity with GAD and dysthymia. Although reporting biases cannot be ruled out, our results are consistent with the hypothesis that, as in Western countries, CSA substantially increases the risk for MD in China.

Association between the ACTN3 R577X polymorphism and female endurance athletes in China

The α-actinin 3 ( ACTN3) gene is absent in 18% of healthy white individuals owing to homozygosity for a premature stop codon polymorphism (rs1815739) and is only expressed in the Z line of fast glycolytic muscle fibres. Previous studies have shown highly significant association between ACTN3 genotype and sprint/power performance, while the nonfunctional allele (577X) was believed to provide an advantage for endurance performance. In this study we tested whether XX genotype was over-represented in Chinese endurance athletes compared to the general population. In a study of 250 Chinese endurance athletes of provincial or national competitive standard and 450 controls, we proved that the ACTN3 XX genotype (21.2 vs. 15.8%; P=0.02) and X allele (51.3 vs. 41.1%; P=0.019) were significantly over-represented in female endurance athletes compared to controls, while no genotype-related differences were observed in male endurance athletes. Besides, the frequency of the ACTN3 XX genotype (28.6%) was the highest in a group of highly elite athletes compared with other groups, which supported the hypothesis that the absence of α-actinin-3 provided some sort of advantage for endurance athletes. Our results indicated that ACTN3 R577X polymorphism was associated with endurance performance in female athletes but not male athletes in China.

Dual-specificity phosphatase 26 is a novel p53 phosphatase and inhibits p53 tumor suppressor functions in human neuroblastoma

Chemoresistance is a major cause of treatment failure and poor outcome in neuroblastoma. In this study, we investigated the expression and function of dual-specificity phosphatase 26 (DUSP26), also known as mitogen-activated protein kinase phophatase-8, in human neuroblastoma. We found that DUSP26 was expressed in a majority of neuroblastoma cell lines and tissue specimens. Importantly, we found that DUSP26 promotes the resistance of human neuroblastoma to doxorubicin-induced apoptosis by acting as a p53 phosphatase to downregulate p53 tumor suppressor function in neuroblastoma cells. Inhibiting DUSP26 expression in the IMR-32 neuroblastoma cell line enhanced doxorubicin-induced p53 phosphorylation at Ser20 and Ser37, p21, Puma, Bax expression as well as apoptosis. In contrast, DUSP26 overexpression in the SK-N-SH cell line inhibited doxorubicin-induced p53 phosphorylation at Ser20 and Ser37, p21, Puma, Bax expression and apoptosis. Using in vitro and in vivo assays, we found that DUSP26 binds to p53 and dephosphorylates p53 at Ser20 and Ser37. In this report, we show that DUSP26 functions as a p53 phosphatase, which suppresses downstream p53 activity in response to genotoxic stress. This suggests that inhibition of this phosphatase may increase neuroblastoma chemosensitivity and DUSP26 is a novel therapeutic target for this aggressive pediatric malignancy.

The endoplasmic reticulum stress-mediated apoptosis signal pathway is involved in sepsis-induced abnormal lymphocyte apoptosis

BACKGROUND/AIM

The mechanisms of abnormal lymphocyte apoptosis in sepsis are only partially defined. The present study was designed to investigate whether the endoplasmic reticulum (ER) is implicated in the extensive apoptosis of lymphocytes in sepsis.

METHODS

C57BL/6 mice were randomized into cecal ligation and puncture (CLP) and sham operation groups. Apoptosis was detected by the TUNEL method and flow cytometry. The expression of glucose-regulated protein 78 (GRP78) and C/EBP homologous protein (CHOP) was detected by RT-PCR and Western blot. The splicing of X box-binding protein-1 (XBP1) mRNA was detected by RT-PCR.

RESULTS

A high degree of lymphocyte apoptosis was observed in the CLP group. Marked induction of GRP78 and accumulation of spliced XBP1 mRNA were observed in the splenocytes from septic mice, indicating activation of unfolded protein responses. Furthermore, both CHOP and its mRNA were markedly upregulated in the CLP group, suggesting that the ER stress response switched to a proapoptotic response.

CONCLUSION

These data demonstrate activation of the unfolded protein response in lymphocytes and that ER stress may contribute to abnormal lymphocyte apoptosis during sepsis. Accordingly, the ER stress-mediated apoptosis pathway may be a novel target in clinical prevention and therapy of sepsis-induced lymphocyte apoptosis.

Neutral Mitochondrial Heteroplasmy Alters Physiological Function in Mice1

Cytoplasmic transfer is an assisted reproductive technique that involves the infusion of ooplasm from a donor oocyte into a recipient oocyte of inferior developmental competence. Although this technique has shown some success for couples with recurrent in vitro fertilization failure, it results in mitochondrial heteroplasmy in the offspring, defined as the presence of two different mitochondrial genomes in the same individual. Because the long-term health consequences of mitochondrial heteroplasmy are unknown, there is a need for appropriate animal models to evaluate any physiological changes of dual mtDNA genotypes. This longitudinal study was designed as a preliminary screen of basic physiological functions for heteroplasmic mice (NZB mtDNA on a BALB/cByJ background). The mice were tested for cardiovascular and metabolic function, hematological parameters, body mass analysis, ovarian reserve, and tissue histologic abnormalities over a period of 15 mo. Heteroplasmic mice developed systemic hypertension that corrected over time and was accompanied by cardiac changes consistent with pulmonary hypertension. In addition, heteroplasmic animals had increased body mass and fat mass compared with controls at all ages. Finally, these animals had abnormalities in electrolytes and hematological parameters. Our findings suggest that there are significant physiological differences between heteroplasmic and control mice. Because ooplasm transfer appears to be consistently associated with mitochondrial heteroplasmy, children conceived through ooplasm transfer should be closely followed to determine if they are at risk for any health problems.

Genetic and pharmacologic evidence that Rac1 GTPase is involved in regulation of platelet secretion and aggregation

BACKGROUND

Rac1 GTPase, a member of the Ras-related Rho GTPase family, is the major Rac isoform present in platelets and has been shown to be involved in cell actin cytoskeleton reorganization and adhesion. Agonists that induce platelet secretion and aggregation also activate Rac1 GTPase, raising the possibility that Rac1 GTPase may be involved in regulation of platelet function.

OBJECTIVES

To rigorously define the role of Rac1 in platelet regulation.

METHODS

We have used a dual approach of gene targeting in mice and pharmacologic inhibition of Rac1 by NSC23766, a rationally designed specific small molecule inhibitor, to study the role of Rac1 in platelet function.

RESULTS

Platelets from mice as well as human platelets treated with NSC23766 exhibited a significant decrease in: (i) active Rac1 species and phosphorylation of the Rac effector, p21-activated kinase; (ii) expression of P-selectin and secretion of adenosine triphosphate induced by thrombin or U46619; and (iii) aggregation induced by adenosine 5'-diphosphate, collagen, thrombin and U46619, a stable analog of thromboxane A(2). NSC23766 did not alter the cAMP or cGMP levels in platelets. Consistent with the requirement of Rac1 for normal platelet function, the bleeding times in Rac1(-/-) mice or mice given NSC23766 were significantly prolonged.

CONCLUSIONS

Our data show that deficiency or inhibition of Rac1 GTPase blocks platelet secretion. The inhibition of secretion, at least in part, is responsible for diminished platelet aggregation and prolonged bleeding times observed in Rac1 knockout or Rac1 inhibitor-treated mice.

Changes in Abdominal Wounds Following Treatment With Sirolimus and Steroids in a Rat Model

Wound healing complications have been observed in patients receiving sirolimus (SLR). This study examined the degree and duration of delayed healing in various protocols using SLR. Sprague-Dawley rats underwent a standard midline abdominal incision and wound closure. Groups of 6 rats each were randomized to receive different doses of SLR (2 and 5 mg/kg) with or without loading dose (10 mg/kg x3 days), and with or without steroids (20 mg/kg x3 days followed by 5 mg/kg for 2 weeks). Rats were humanely killed on postoperative days 5, 10, or 15. Wound breaking force was measured using the EHMI BIAX-II instrument and tensile strength was calculated. Wounds in control animals had gradual increase in tensile strength during the 15-day observation. In contrast, high and loading doses of SLR caused reduction in wound strength until day 10, but the wounds' tensile strength became equivalent to control by day 15. The addition of steroids prolonged wound recovery with low doses of SLR until day 15 and had very profound effects on healing in high-dose SLR-treated animals (>50% reduction) that continued beyond the 2 weeks of observation. Low doses of SLR in non-steroid-treated animals had a short-term (5-day) impact on wound healing; high dose and loading doses delayed healing for 10 to 15 days. The addition of steroids had a synergistic effect on delayed wound healing, particularly in animals receiving high-dose SLR, which demonstrated prolonged wound weakness. These results may provide practical guidelines for postoperative introduction of SLR in the context of various clinical protocols.

A prodrug approach toward the development of water soluble fluoroquinolones and structure--activity relationships of quinoline-3-carboxylic acids

A fluoroquinolone prodrug, PA2808, was prepared and shown to convert to the highly active parent drug PA2789. In vitro and in vivo activation of PA2808 by alkaline phosphatase was demonstrated using disk diffusion and rat lung infection models. The water solubility of PA2808 showed a marked increase compared to PA2789 over a pH range suitable for aerosol drug delivery. A total of 48 analogues based on PA2789 were prepared and screened against a panel of Gram-positive and Gram-negative pathogens. Incorporating a cyclopropane-fused pyrrolidine (amine) at C-7 resulted in some of the most active analogues.

[Application of the IFN-gamma ELISPOT assay for monitoring CD8(+) T cell response to specific antigen from hepatocellular carcinoma patients]

OBJECTIVE

To study the specific CD8(+) T cell response to HLA-A2 binding peptide Flu p58-66 from HLA-A2-positive hepatocellular carcinoma patients and healthy donors.

METHODS

The CD8(+) T cells were separated with immunobeads from PBMC of HCC patients and healthy donors, respectively. The irradiated autologous CD8(-) PBMC or isolated dendritic cells were loaded with influenza matrix peptide as APC. After 7 days' culture, the frequency of effector cells to secrete IFN-gamma in response to Flu p58-66 was detected in ELISPOT assay.

RESULTS

With CD8(-) PBMC as APC, the frequency of effector cells to secrete IFN-gamma in response to Flu peptide was 22 +/- 9/well in HCC patients (n = 8) and 59 +/- 27/well in healthy donors (n = 12) when the effector cells were 5 x 10(4)/well (P < 0.01). To compare the antigen-presenting capacity of APC derived from 5 healthy donors, DC was better than CD8(-) PBMC.

CONCLUSION

Although the frequency of specific effector CTL to secrete IFN-gamma in response to Flu p58 - 66 was lower in HCC patients than in healthy individuals, the majority of HCC patients have the cellular immunity specific to antigen peptides.

Synergistic enhancement of apoptosis by DNA- and cytoskeleton-damaging agents: a basis for combination chemotherapy of cancer

Actinomycin D (AD)-induced apoptosis in CMK-7 cells is greatly accelerated by cytoskeletal poisons such as colcemid (CL) and cytochalasin D (CD). This phenomenon is important in the combination chemotherapy of cancer so that its generality was investigated. Four human leukemia and two human solid tumor cell lines were treated with combinations of one DNA-damaging agent [AD, mitomycin C (MMC), or etoposide (VP- 16)] and one cytoskeletal poison [CL, CD, or vinblastine (VBL)]. The apoptosis was monitored by assaying caspase-3 activity and the DNA cleavage ratio. The caspase-3 activation in all leukemia and HeLa S3 cell lines was, except for a few cases, 1.3-to 6.0-fold enhanced by combinations of the DNA-damaging agent with a cytoskeletal poison. The DNA cleavage ratio as well as the dead cell ratio was also 1.4-to 23.7-fold enhanced in CMK-7, U-937, HeLa S3, and Colo320 DM cell lines by the combinations of AD with CL, CD, or VBL. The combination index for caspase-3 activation by AD and CL in U-937 cells was smaller than 1 at Fa of more than 0.03. Thus, apoptosis in many tumor cell lines is synergistically enhanced by various combinations of DNA- and cytoskeleton-damaging agents.

Chemokine receptor 1 knockout abrogates natural killer cell recruitment and impairs type-1 cytokines in lymphoid tissue during pulmonary granuloma formation

Mice with targeted mutation of chemokine receptor 1 (CCR1) were used to assess the contribution of CCR1 agonists to local, regional, and systemic inflammatory-related events during experimental pulmonary granuloma formation. Models of Th1 (type-1) and Th2 (type-2) cell-mediated lung granulomas were induced in wild-type (CCR+/+) and knockout (CCR1-/-) mice by embolizing Sepharose beads coupled to the purified protein derivative of Mycobacterium bovis or soluble antigens derived from Schistosoma mansoni eggs. Morphometric analysis indicated that granuloma sizes were unchanged in CCR1-/- mice, but flow cytometric analyses of dispersed granulomas revealed that natural killer cell recruitment to type-1 lesions was abrogated by 60%. Analysis of cytokine production by draining lymph node cultures showed altered expression in CCR1-/- mice characterized by reduced interleukin-2 and interferon-gamma in the type-1 response, and enhanced interleukin-5 and interleukin-13 in the type-2 response. Peripheral blood leukocytosis was also enhanced in the type-1 but not the type-2 response. These findings suggest that CCR1 agonists contribute to multiple immunoinflammatory events in the type-1 granulomatous response with natural killer cell accumulation being particularly sensitive to CCR1 disruption. Although functional efficacy of granulomas may be altered, chemokine redundancy and cytokine reserve seem to make the bulk of the exudative response resistant to CCR1 disruption.

Cytoskeletal disruption accelerates caspase-3 activation and alters the intracellular membrane reorganization in DNA damage-induced apoptosis

In actinomycin D (AD)-induced apoptosis, caspase-3 activation and DNA cleavage in human megakaryoblastic leukemia CMK-7 cells were greatly accelerated by tubulin and actin polymerization inhibitors [e.g., colcemid (CL) and cytochalasin D (CD), respectively], but the acceleration was not found with Taxol or phalloidin. A decrease in mitochondrial transmembrane potential, release of cytochrome c into the cytosol, and cleavage of procaspase-9 to its active form preceded the activation of caspase-3 and, moreover, all of these events began earlier and/or proceeded faster in cells treated with AD plus CL or CD than in cells treated with AD only. These results suggest that cytoskeletal disruption in the apoptotic cells promotes damage of the mitochondrial membrane, resulting in the enhanced release of cytochrome c necessary for the activation of caspase-9 that initiates the caspase cascade. On the other hand, apoptotic bodies were rapidly formed from cells treated with AD and CL, but were suppressed when treated with AD and CD. Intracellular membranes and the actin system were reorganized to surround the nuclear fragments in the AD- and CL-treated cells, but such a membrane system was not formed in the presence of CD, implying that the apoptotic bodies are formed via reorganization of intracellular membranes under regulation by actin polymerization. Thus, the cytoskeletal change in CMK-7 cells has a strong effect on the early biochemical process as well as on the later morphologic process in AD-induced apoptosis.

Interleukin 4 and 13 participation in mycobacterial (type-1) and schistosomal (type-2) antigen-elicited pulmonary granuloma formation: multiparameter analysis of cellular recruitment, chemokine expression and cytokine networks

The contribution of IL-4 and IL-13 to inflammation and cytokine responses was compared in mice with types-1 or -2 pulmonary granulomas (GR) elicited by beads bound to antigens of Mycobacteria bovis (PPD) or Schistosoma mansoni eggs (SEA). Type-2 SEA-GR produced the most IL-4 and IL-13. Type-1 PPD-GR produced detectable IL-13, but not IL-4. Mice were treated with anti-IL4 or anti-IL-13 Abs, then lesion size/composition, cytokine/chemokine mRNA and lymph node cytokines were measured. Type-1 GRs resisted individual Abs, but combined Abs augmented lesions by 20%. In contrast, anti-IL-4 abrogated type-2 GR by 30-40% and eosinophil recruitment by 60%. Anti-IL-13 abrogated type-2 GR by 20-30% with no effect on eosinophils. Combined depletion reduced lesion area by 60% and eosinophils by more than 80%. In type-1 GR lungs, anti-IL-4 and anti-IL-13 augmented IFNgamma and TNFalpha mRNA. In type 2 lungs, anti-IL-13 did likewise, but anti-IL-4 decreased TNFalpha without affecting IFNgamma mRNA. In both responses, IL-4 promoted MCP-1 and MCP-5 mRNA, but IL-13 inhibited chemokines in type-1 GR. In lymph nodes, anti-IL-4, but not anti-IL-13, abrogated type-2 cytokines. In fact, IL-13 down-regulated itself and other type-2 cytokines. In summary, IL-4 and IL-13 have common and disparate regulatory functions in types 1 and 2 responses.

The controlled introduction of multiple negative charge at single amino acid sites in subtilisin Bacillus lentus

The use of methanethiosulfonates as thiol-specific modifying reagents in the strategy of combined site-directed mutagenesis and chemical modification allows virtually unlimited opportunities for creating new protein surface environments. As a consequence of our interest in electrostatic manipulation as a means of tailoring enzyme activity and specificity, we have adopted this approach for the controlled incorporation of multiple negative charges at single sites in the representative serine protease, subtilisin Bacillus lentus (SBL). A series of mono-, di- and triacidic acid methanethiosulfonates were synthesized and used to modify cysteine mutants of SBL at positions 62 in the S2 site, 156 and 166 in the S1 site and 217 in the S1' site. Kinetic parameters for these chemically modified mutant (CMM) enzymes were determined at pH 8.6 under conditions which ensured complete ionization of the unnatural amino acid side-chains introduced. The presence of up to three negative charges in the S1, S1' and S2 subsites of SBL resulted in up to 11-fold lowered activity, possibly due to interference with oxyanion stabilization of the transition state of the hydrolytic reactions catalyzed. Each unit increase in negative charge resulted in a raising of K(M) and a reduction of k(cat). However, no upper limit was observed for increases in K(M), whereas decreases in k(cat) reached a limiting value. Comparison with sterically similar but uncharged CMMs revealed that electrostatic effects of negative charges at positions 62, 156 and 217 are detrimental, but are beneficial at position 166. These results indicate that the ground-state binding of SBL to the standard substrate, Suc-AAPF-pNA, to SBL is reduced, but without drastic attenuation of catalytic efficiency, and show that SBL tolerates high levels of charge at single sites.

Toward tailoring the specificity of the S1 pocket of subtilisin B. lentus: chemical modification of mutant enzymes as a strategy for removing specificity limitations

In both protein chemistry studies and organic synthesis applications, it is desirable to have available a toolbox of inexpensive proteases with high selectivity and diverse substrate preferences. Toward this goal, we have generated a series of chemically modified mutant enzymes (CMMs) of subtilisin B. lentus (SBL) possessing expanded S(1) pocket specificity. Wild-type SBL shows a marked preference for substrates with large hydrophobic P(1) residues, such as the large Phe P(1) residue of the standard suc-AAPF-pNA substrate. To confer more universal P(1) specificity on S(1), a strategy of chemical modification in combination with site-directed mutagenesis was applied. For example, WT-SBL does not readily accept small uncharged P(1) residues such as the -CH(3) side chain of alanine. Accordingly, with a view to creating a S(1) pocket that would be of reduced volume providing a better fit for small P(1) side chains, a large cyclohexyl group was introduced by the CMM approach at position S166C with the aim of partially filling up the S(1) pocket. The S166C-S-CH(2)-c-C(6)H(11) CMM thus created showed a 2-fold improvement in k(cat)/K(M) with the suc-AAPA-pNA substrate and a 51-fold improvement in suc-AAPA-pNA/suc-AAPF-pNA selectivity relative to WT-SBL. Furthermore, WT-SBL does not readily accept positively or negatively charged P(1) residues. Therefore, to improve SBL's specificity toward positively and negatively charged P(1) residues, we applied the CMM methodology to introduce complementary negatively and positively charged groups, respectively, at position S166C in S(1). A series of mono-, di-, and trinegatively charged CMMs were generated and all showed improved k(cat)/K(M)s with the positively charged P(1) residue containing substrate, suc-AAPR-pNA. Furthermore, virtually arithmetic improvements in k(cat)/K(M) were exhibited with increasing number of negative charges on the S166C-R side chain. These increases culminated in a 9-fold improvement in k(cat)/K(M) for the suc-AAPR-pNA substrate and a 61-fold improvement in suc-AAPR-pNA/suc-AAPF-pNA selectivity compared to WT-SBL for the trinegatively charged S166C-S-CH(2)CH(2)C(COO(-))(3) CMM. Conversely, the positively charged S166C-S-CH(2)CH(2)NH(3)(+) CMM generated showed a 19-fold improvement in k(cat)/K(M) for the suc-AAPE-pNA substrate and a 54-fold improvement in suc-AAPE-pNA/suc-AAPF-pNA selectivity relative to WT-SBL.

Application of recombinant human granulocyte colony stimulating factor in children with acute myeloid leukemia

OBJECTIVE

To evaluate the effect of recombinant human granulocyte colony stimulating factor (rhG-CSF) on accelerating neutrophil recovery and decrease fatal infections for childhood acute myeloid leukemia (AML).

METHODS

From November 1992 to March 1997, 45 patients were enrolled into our study and 15 were newly diagnosed. All were treated with high dose chemotherapy combined with rhG-CSF.

RESULTS

Of 15 newly diagnosed patients, 13 achieved complete remission (CR) after one course of therapy and 2 achieved CR after two courses of therapy. For newly diagnosed patients, the durations of absolute neutrophil counts (ANC) < 0.5 x 10(9)/L were 5 days and 10 days in rhG-CSF group and control group respectively (P < 0.05). The incidences of infection of these two groups were 40% and 60% respectively (P < 0.05). As for patients who received intensive therapy, the durations of ANC < 0.5 x 10(9)/L were 5 days and 8 days in rhG-CSF group and control group, respectively (P < 0.05), and the incidences of infection were 25% and 44.4% respectively (P < 0.05).

CONCLUSIONS

The application of rhG-CSF in children with AML after chemotherapy may hasten the hematopoietic recovery. The duration of neutropenia was shortened by 3-4 days, and the incidence of fatal infection was reduced. rhG-CSF does not stimulate AML growth in vivo.

A combinatorial approach to chemical modification of subtilisin Bacillus lentus

The reaction between methanethiosulfonate reagents and cysteine mutants of subtilisin is quantitative and can be used to prepare chemically modified mutant enzymes (CMMs) with novel properties. The virtually unrestricted structural variations possible for CMMs presents a preparative and screening challenge. To address this, a rapid combinatorial method for preparing and screening the activities of CMMs has been developed.

[The relationship between p53 mutation and esophageal cancer biological behavior]

OBJECTIVE

To investigate the relationship between p53 mutation and esophageal cancer biological behavior as well as its prognostic role in esophageal cancer.

METHOD

Mutations in exon 5-8 of p53 were screened in 30 sporadic esophageal cancers by a combination of PCR-SSCP and PCR-direct DNA silver sequencing.

RESULTS

Mutations were found in 11 cases (36.7%). There were 9 point mutations, including 4 missense mutations, 2 nonsense mutations, 3 silent mutations. The other 2 cases were frameshift mutations due to base insertion and deletion. With statistical analysis, the p53 mutation rate was 56.3% in moderately and poorly-differentiated esophageal cancers, 14.3% in well-differentiated cases, with a highly significant difference between the two groups (P=0.025). The mutation rate of the cancers with all layers invaded (52.6%) was remarkably higher than that of the cancers without all layers invaded (9.1%)(P=0.024). A significantly higher rate of p53 mutation was also seen in cases with lymph nodes metastasis (61.5%) than in cases with no lymph nodes metastasis (17.6%) (P=0.024).

CONCLUSION

The data suggest that there is a strong correlation between the presence of p53 mutation and the biological behavior of human esophageal cancer, such as histologic differentiation, invasion stage, and regional lymph nodes metastasis. Detection of p53 mutation can be helpful in identifying more progressive esophageal cancer and assessing prognosis. The study also discussed the dominant negative effect of p53 and the genetic effect of silent mutation.

[The effect of Rhodiola capsules on oxygen consumption of myocardium and coronary artery blood flow in dogs]

It has been proved that Rhodiola Capsules can obviously decrease the oxygen consumption of myocardium and oxygen consumption index in anesthetic dogs, decrease the coronary artery resistance, but have no marked effect on the coronary artery blood flow. The Capsules also have the function of decreasing blood presure and slowing heart rate.

In vitro selection and regeneration of cotton resistant to high temperature stress

Cell suspension cultures of cotton (Gossypium hitirsutum L. cv. Coker 312) were exposed to various temperature:time treatments in order to select cell lines resistant to high temperature stress. Cells were exposed to 45°C for 3 h each day until the total accumulated hours of stress were: 0 h, 10 h, 75 h, 100 h, or 105 h (81 h pulsed then 24 h continuous). After the stress treatments, the cells were plated onto embryo development medium and plants were recovered. The embryogenic calli that were recovered were subcultured monthly for 6 months and tested for increased resistance to the temperature:time treatments previously determined to be lethal and to water stress as imposed by PEG. All of the selected cell lines were more resistant to both types of stress than the control cell lines. Leaf tissue of stress selected (Ro) formed and maintained callus growth when incubated at 38°C; whereas, tissue excised from nonselected controls rarely formed callus and calli which did form quickly became necrotic. These cells and plants will provide a tool for determining the mechanisms involved in resistance to high temperature stress.