[Prognostic analysis of children with Philadelphia chromosome-like acute lymphoblastic leukemia common genes].

Objective: To summarize the clinical data and prognosis of children with Philadelphia chromosome-like acute lymphoblastic leukemia (Ph-like ALL) common genes. Methods: This was a retrospective cohort study.Clinical data of 56 children with Ph-like ALL common gene cases (Ph-like ALL positive group) treated from January 2017 to January 2022 in the First Affiliated Hospital of Zhengzhou University, Henan Children's Hospital, Henan Cancer's Hospital and Henan Provincial People's Hospital were collected, 69 children with other high-risk B cell acute lymphoblastic leukemia (B-ALL) at the same time and the same age were selected as the negative group. The clinical characteristics and prognosis of two groups were analyzed retrospectively. Comparisons between groups were performed using Mann-Whitney U test and χ2 test. Kaplan-Meier method was used for survival curve, Log-Rank test was used for univariate analysis, and the Cox regression model was used for multivariate prognosis analysis. Results: Among 56 Ph-like ALL positive patients, there were 30 males and 26 females, and 15 cases were over 10 years old. There were 69 patients in Ph-like ALL negative group. Compared with the negative group, the children in positive group were older (6.4 (4.2, 11.2) vs. 4.7 (2.8, 8.4) years), and hyperleukocytosis (≥50×109/L) was more common (25% (14/56) vs. 9% (6/69)), the differences were statistically significant (both P<0.05). In the Ph-like ALL positive group, 32 cases were positive for IK6 (1 case was co-expressed with IK6 and EBF1-PDGFRB), 24 cases were IK6-negative, of which 9 cases were CRLF2 positive (including 2 cases with P2RY8-CRLF2, 7 cases with CRLF2 high expression), 5 cases were PDGFRB rearrangement, 4 cases were ABL1 rearrangement, 4 cases were JAK2 rearrangement, 1 case was ABL2 rearrangement and 1 case was EPOR rearrangement. The follow-up time of Ph-like ALL positive group was 22 (12, 40) months, and 32 (20, 45) months for negative group. The 3-year overall survival (OS) rate of positive group was significantly lower than the negative group ((72±7) % vs. (86±5) %, χ2=4.59, P<0.05). Compared with the 24 IK6-negative patients, the 3-year event free survival (EFS) rate of 32 IK6 positive patients was higher, the difference was statistically significant ((88±9) % vs. (65±14) %, χ2=5.37, P<0.05). Multivariate Cox regression analysis showed that the bone marrow minimal residual disease (MRD) not turning negative at the end of first induction (HR=4.12, 95%CI 1.13-15.03) independent prognostic risk factor for patient with Ph-like ALL common genes. Conclusions: Children with Ph-like ALL common genes were older than other high-risk B-ALL patients at diagnosis, with high white blood cells and lower survival rate. The bone marrow MRD not turning negative at the end of first induction were independent prognostic risk factor for children with Ph-like ALL common gene.

[Analysis of 8 cases of asparaginase related cerebral venous sinus thrombosis in children].

Objective: To summarize the clinical features, treatment and prognosis of asparaginase (ASP) related cerebral venous sinus thrombosis (CVST). Methods: Clinical profiles including age, sex, first symptoms, coagulation function, imaging findings, ASP type, treatment and prognosis of eight acute lymphoblastic leukemia (ALL) or lymphoblastic lymphoma (LBL) children with ASP related CVST at the Department of Pediatrics, First Affiliated Hospital of Zhengzhou University from November 2016 to October 2021 were analyzed retrospectively. Results: Eight CVST children were all male, including 6 ALL and 2 LBL, with the onset age ranged from 5 to 15 years, 6 cases occurred in the stage of first induction remission, and the initial symptom were mainly epileptic seizures (7 cases). Magnetic resonance imaging combined magnetic resonance venography (MRV) showed the most common site of venous sinus enlargement was superior sagittal sinus (8 cases). Secondary cerebral hemorrhage was found in 5 cases. D-dimer elevated on the day of onset in all cases. Three patients were treated with intravascular mechanical thrombectomy and thrombolysis combined with anticoagulant therapy, 3 patients were treated with continuous anticoagulant therapy only, 2 patients were not treated with anticoagulant therapy. MRV follow-up for 3 months showed that the thrombi in patients were almost completely absorbed except in 2 patients who were not treated with anticoagulant therapy. Thrombolysis combined with anticoagulant therapy was the fastest way for thrombosis absorption. Among 8 patients, 1 died of early recurrence of ALL, and 7 patients accepted further asparaginase and no CVST recurrence or progression was found. There were no sequelae of nervous system except 1 patient with left upper limb muscle strength impairment. Conclusions: ASP related CVST is more common in older male children and the prognosis is good. ASP related CVST occurred mostly in the stage of first induction remission, and most initial manifestation is epileptic seizure. The superior sagittal region is a common site of thrombus, magnetic resonance imaging combined with MRV is helpful for accurately diagnosis. Timely anticoagulant treatment can improve the prognosis, and mechanical thrombectomy and thrombolysis can quickly recanalize the vessel.

[Clinical characteristics and prognosis of 83 children with newly treated hepatoblastoma].

Objective: To investigate the clinical features, survival and prognostic risk factors of children with hepatoblastoma (HB). Methods: Clinical data of 83 children with newly treated HB at the Department of Hematology and Oncology, Children's Hospital, the First Affiliated Hospital of Zhengzhou University from January 2012 to October 2019 were analyzed retrospectively. The sex, age, first clinical manifestations, pretreatment extent of disease (PRETEXT) stages, pathological types, initial alpha-fetoprotein (AFP), treatment methods and treatment outcome of all patients were summarized. The children diagnosed before 2018 were treated with "Wuhan Protocol", and those who diagnosed after 2018 were treated with the "Expert Consensus for Multidisciplinary Management of Hepatoblastoma"(CCCG-HB-2016) protocol. Kaplan-Meier survival analysis was used to calculate the survival rate, Log-Rank test was used in univariate analysis, and the Cox regression model was used in multivariate prognosis analysis. Results: Among 83 cases, there were 51 males and 32 females. The age of onset was 25.2 (9.0, 34.0) months old, and 64 cases (77%) were under 3 years old. The most common first clinical manifestation was abdominal mass in 45 cases (54%). There were 8 cases of PRETEXT stage Ⅰ, 43 cases of stage Ⅱ, 20 cases of stage Ⅲ and 12 cases of stage Ⅳ. During the follow-up period of 40 (17, 63) months, the 1-year overall survival (OS) rate and event-free survival (EFS) rate were (84±4) % and (79±5) %, respectively, and 5-year OS rate and EFS rate were (78±5) % and (76±5) %, respectively. Fifty-five cases were treated with "Wuhan Protocol", and the 5-year OS and EFS rate were (73±6) % and (71±6) %, respectively. Twenty-eight cases were treated with CCCG-HB-2016 protocol, and the 5-year OS and EFS rate were (88±7) % and (82±9) %, respectively. Multivariate COX regression analysis showed that AFP did not turn negative after 3 courses of postoperative chemotherapy (HR=9.228, 95%CI 1.017-83.692) and PRETEXT stage Ⅳ (HR=6.587, 95%CI 1.687-25.723) were independent risk factors affecting the prognosis of children with HB. Conclusions: The "Wuhan Protocol" and CCCG-HB-2016 protocol were effective in the treatment of children with HB. AFP did not turn negative after 3 courses of postoperative chemotherapy and PRETEXT stage Ⅳ were independent risk factors affecting the prognosis of children with HB.

[Preoperative video distraction alleviates separation anxiety and improves induction compliance of preschool children: a randomized controlled clinical trial].

Objective: To explore the effect of video distraction on preoperative separation anxiety and induction compliance of preschool children receiving strabismus surgery under general anesthesia. Methods: In this prospective trial, 80 children aged 3 to 6 years scheduled for strabismus surgery under inhalation anesthesia were randomly allocated to one of two groups, a control group and a video distraction group, with 40 cases in each group. Children in the video distraction group continuously watched videos from waiting in the holding area, separating with parents, entering the operating room and induction of anesthesia, while children in the control group didn't watch videos during the same process. The modified Yale Preoperative Anxiety Scale (mYPAS) of children were recorded upon arriving at the holding area(T1)and separating with parents(T2). Induction Compliance Checklist (ICC) score was recorded when the anesthesia induction was performed. The emergence time, the occurrence rate of adverse events in post-anesthesia care unit (PACU) including nausea and vomiting, laryngospasm, severe cough, hypoxemia and sinus bradycardia, incidence of postoperative adverse reactions such as pain, dizziness, nausea and vomiting and lethargy, the parents' satisfaction of anesthesia were also assessed. Results: There were no significant difference in mYPAS score and the proportion of mYPAS score>30 between 2 groups at T1 (all P>0.05). At T2, the mYPAS score and the proportion of mYPAS score>30 in video distraction group were (34.41±13.23) and 52.50%, which were lower than those in control group (50.64±20.96, 87.50%) with statistically significant difference (all P<0.05). The ICC score of video distraction group was lower than that of the control group, which was (1.83±2.26) vs (4.03±2.99), and the difference was statistically significant (P<0.05). The proportion of children with ICC score=0 in video distraction group was 37.50%, which was higher than that in the control group (12.50%), while the proportion of children with ICC score=4-10 was lower than that of the control group, which was 17.50% vs 45.00%, and the difference was statistically significant (P<0.05). No significant intergroup differences were observed in emergence time, incidence of adverse events in PACU, and incidence of postoperative adverse reactions (P>0.05). The parents' satisfaction of anesthesia in the video distraction group was (9.23±0.89), which was higher than that in the control group (8.63±1.23), with statistically significant (P<0.05). Conclusion: Preoperative video distraction alleviates separation anxiety, improves induction compliance of preschool children receiving strabismus surgery under general anesthesia, and increases the parents' satisfaction of anesthesia.

Novel long non-coding RNA LBX2-AS1 indicates poor prognosis and promotes cell proliferation and metastasis through Notch signaling in non-small cell lung cancer.

OBJECTIVE: Recent reports have suggested that long non-coding RNA LBX2 antisense RNA 1 (LBX2-AS1) acts as an important regulator in cancer progression. This study aimed to investigate the clinical significance of LBX2-AS1 in non-small cell lung cancer (NSCLC) patients and its biological functions. PATIENTS AND METHODS: The expressions of LBX2-AS1 were examined in 165 paired NSCLC tissues and adjacent normal tissues from NSCLC patients by qRT-PCR. The clinical significance of LBX2-AS1 was determined using a series of statistical methods. The effects of LBX2-AS1 knockdown on NSCLC cell proliferation, migration, and invasion were investigated by CCK-8 assays, colony formation assays, EdU proliferation assays, Wound healing assays, and transwell assays. The promotive roles of LBX2-AS1 on Notch1 signal were determined using RT-PCR and Western blot. RESULTS: We found that LBX2-AS1 was highly expressed in NSCLC tissues and cell lines. The increased levels of LBX2-AS1 were observed to be positively correlated with TNM stage, histological grade, and lymph node metastasis. Furthermore, the Kaplan-Meier survival curves indicated that patients with higher expressions of LBX2-AS1 had unfavorable overall survival. Lost-of-functions assays revealed that the knockdown of LBX2-AS1 in H1299 and A549 cells inhibited cell proliferation, migration, and invasion. Mechanistic studies revealed that the suppression of LBX2-AS1 resulted in the reduced expressions of Notch1, p21, and Hes1, suggesting that LBX2-AS1 might promote the activation of the Notch pathway. CONCLUSIONS: Our study identified a novel NSCLC-related lncRNA LBX2-AS1, which may represent a novel prognostic biomarker and a potential therapeutic target for NSCLC.

miR-30d, miR-181a and miR-199a-5p cooperatively suppress the endoplasmic reticulum chaperone and signaling regulator GRP78 in cancer.

GRP78, a major endoplasmic reticulum chaperone and signaling regulator, is commonly overexpressed in cancer. Moreover, induction of GRP78 by a variety of anti-cancer drugs, including histone deacetylase inhibitors, confers chemoresistance to cancer, thereby contributing to tumorigenesis. Thus, therapies aimed at decreasing GRP78 levels, which results in the inhibition of tumor cell proliferation and resensitization of tumor cells to chemotherapeutic drugs may hold promise for cancer treatment. Despite advances in our understanding of GRP78 actions, little is known about endogenous inhibitors controlling its expression. As endogenous regulators, microRNAs (miRNAs) play important roles in modulating gene expression; therefore, we sought to identify miRNA(s) that target GRP78, under the hypothesis that these miRNAs may serve as therapeutic agents. Here, we report that three miRNAs (miR-30d, miR-181a, miR-199a-5p) predicted to target GRP78 are down-regulated in prostate, colon and bladder tumors, and human cancer cell lines. We show that in C42B prostate cancer cells, these miRNAs down-regulate GRP78 and induce apoptosis by directly targeting its 3' untranslated region. Importantly, we demonstrate that the three miRNAs act cooperatively to decrease GRP78 levels, suggesting that multiple miRNAs may be required to efficiently control the expression of some genes. In addition, delivery of multiple miRNAs by either transient transfection or lentivirus transduction increased the sensitivity of cancer cells to the histone deacetylase inhibitor, trichostatin A, in C42B, HCT116 and HL-60 cells. Together, our results indicate that the delivery of co-transcribed miRNAs can efficiently suppress GRP78 levels and GRP78-mediated chemoresistance, and suggest that this strategy holds therapeutic potential.

Twenty-year follow-up of the Carpentier-Edwards standard porcine bioprosthesis in the Oriental population.

AIM: The 20-year period long-term results of porcine bioprosthetic valve use are limited. In addition, the majority of these reports come from Western countries. Given the scanty information reported in Oriental countries, this study was therefore designed to examine 20-year long-term results in patients who received a Carpentier-Edwards porcine bioprosthetic valve in an effort to contribute further information on the long-term clinical performance of porcine prosthetic valves from a viewpoint of results in the Oriental population. METHODS: From July 1979 to April 2001, 82 patients received valve replacement with a standard Carpentier-Edwards porcine valve. There were 40 men and 42 women with a mean age of 42.3+/-15.1 years (range 16 to 73 years). Follow-up time extended more than 20 years (mean 10.9+/-3.2 years, range 0.5 to 21.5 years ) for a total of 719.5 patient-years. RESULTS: The overall operative mortality was 16.9% (14 of 83 procedures). At 5, 10, 15, and 20 years, the actuarial survival rate of patients was 71.7%, 66.9%, 55.5%, and 44.4%, respectively. Actuarial estimates of freedom from structural valvular deterioration (SVD) at 5, 10, 15, and 17 years were 96.3%, 64.0%, 24.3%, and 24.3%, respectively; from reoperation 96.3%, 64.5%, 24.5%, and 24.5%; from operated valvular endocarditis 96.8%, 92.6%, 92.6%, and 92.6%; and from overall thromboembolism 96.3%, 88.5%, 67.2%, and 52.2%. In normal sinus rhythm, actuarial estimates of freedom from thromboembolism at 5, 10, 15, and 17 years were 100.0%, 100.0%, 81.8%, and 81.8%, respectively. Whereas for those in patients with atrial fibrillation, the estimates of freedom from thromboembolism were 94.5%, 82.4%, 57.7%, and 38.5%. CONCLUSION: This study demonstrates the very satisfactory 20-year period long-term performance of freedom from bleeding events, thromboembolism (except in patients with atrial fibrillation), and valvular endocarditis in Oriental patients undergoing replacement with a porcine valve. However, the remarkable rate of SVD and reoperation ensued at 6 years after bioprosthesis implanted which does not differ from the series reported from Western countries.

Oestrogen attenuates coronary vasoconstriction after angioplasty: role of endothelin-1.

BACKGROUND AND AIMS: There were controversies as to whether endothelin-1 is released after coronary angioplasty. We sought to determine whether endothelin-1 is released after coronary angioplasty and whether oestrogen administration can affect coronary vasomotor tone by reducing endothelin-1 concentrations. METHODS: The study was designed to prospectively investigate 24 consecutive patients scheduled for elective coronary angioplasty. Patients were randomized into two groups according to whether they did not (group 1, n = 12) or did (group 2, n = 12) have intracoronary treatment with oestrogen. Quantitative coronary angiography was monitored at baseline, immediately after successful angioplasty, and 15 min after the last deflation. Blood samples for measuring the levels of endothelin-1 were drawn from the ascending aorta and the coronary sinus simultaneously before angioplasty and 15 min after balloon dilatation. RESULTS: The diameters of the coronary artery at the dilated segments were significantly reduced 15 min after dilation compared with those immediately after dilation in group 1 from 3.20 +/- 0.22 to 2.30 +/- 0.23 mm (P < 0.001), respectively. The vasoconstriction was significantly blunted in group 2. The endothelin-1 levels from the coronary sinus rose significantly, by 29%, 15 min after angioplasty in group 1, which was attenuated after administering oestrogen. Significant correlation was found between the changes of coronary vasomotion of the dilated segment and endothelin-1 levels (r = 0.70, P = 0.01). CONCLUSION: Endothelin-1 is released into the coronary circulation after angioplasty, and this vasoactive substance may contribute to the occurrence of vasoconstriction. The vasoconstriction is attenuated by oestrogen by reducing the endothelin-1 levels. This finding provided a new strategy to treat coronary vasoconstriction after angioplasty.

Effect of pravastatin on myocardial protection during coronary angioplasty and the role of adenosine.

Pravastatin has been shown, in an experimental model of ischemia reperfusion, to increase adenosine levels, which exert a potent and protective effect on the heart. The purpose of this study was to investigate whether pravastatin can provide cardioprotection by increased production of adenosine in patients undergoing coronary angioplasty, a clinical model of ischemia reperfusion. Thirty-five hyperlipidemic patients who underwent elective angioplasty for a major epicardial coronary artery were randomly allocated to either 3-month pravastatin or placebo before catheterization. In the placebo group, the mean ST-segment shift during the second balloon inflation was similar that observed during the first inflation, whereas in the preconditioned patients, the shift was significantly less, which is consistent with ischemic preconditioning. In the pravastatin-treated patients, the changes of ST-segment shift were similar between the first and second balloon inflations. In contrast, the patients who received aminophylline developed higher ST-segment shifts during the first and second inflations than those in the pravastatin-treated group alone. Measurements of chest pain score and myocardial lactate extraction ratios during inflation mirrored those of the ST-segment shift. The present study demonstrates that administration of pravastatin results in a significant gain in tolerance to ischemia during angioplasty. The effect of pravastatin was abolished by aminophylline, suggesting that the cardioprotective effect of pravastatin may result from activation of adenosine receptors.

Differential lipogenic effects of cilostazol and pentoxifylline in patients with intermittent claudication: potential role for interleukin-6.

Cilostazol, a novel oral phosphodiesterase inhibitor, has shown consistent improvement in exercise tolerance in patients with intermittent claudication (IC). In addition to this effect, cilostazol has previously been shown to have beneficial effects on the dyslipidemia, i.e., combination of high triglycerides with low high-density-lipoprotein cholesterol (HDL-C) levels. Interleukin-6 (IL-6) suppresses the activity of lipoprotein lipase, which modulates the metabolism of triglycerides and HDL-C. To determine whether a reduction of IL-6 contributes to the improvement of lipid profiles, we prospectively investigated the effect of cilostazol (n=16, 100 mg, twice daily) on the changes of lipid profiles and on the association with the changes of IL-6 compared with those of pentoxifylline (n=16, 400 mg, bid) in patients with IC. After eight weeks of administration of cilostazol to patients with IC, walking distances were increased, associated with a 29% decrease in plasma triglycerides and a 13% increase in HDL-C. No significant changes of lipid profiles in the pentoxifylline and placebo groups were observed although a similar improvement in walking distances was achieved in the pentoxifylline group. IL-6 levels were significantly reduced in patients receiving cilostazol as compared with those receiving placebo or pentoxifylline. The cilostazol-induced changes in the IL-6 were positively related to those of triglycerides in the cilostazol group (r=0.63, P<0.05) and negatively related to those of HDL-C (r=-0.55, P<0.05). These findings suggest that in addition to consistent improvement of exercise tolerance, cilostazol may improve lipid profiles by reducing IL-6 release. However, pentoxifylline did not affect lipid profiles although a similar improvement of maximal walking distance (MWD) was achieved.

Differential effects of cilostazol and pentoxifylline on vascular endothelial growth factor in patients with intermittent claudication.

Cilostazol is a new phosphodiesterase inhibitor with anti-platelet and vasodilatory properties. Cilostazol and pentoxifylline are the only two drugs that have been approved for the treatment of patients with intermittent claudication. However, the mechanisms by which exercise tolerance is improved remain unclear. Vascular endothelial growth factor (VEGF) is a potent endothelial mitogen that results in angiogenesis when overexpressed in human subjects. To assess the potential role of VEGF in the improvement in exercise tolerance, we investigated plasma levels of VEGF in 50 patients with intermittent claudication who were allocated randomly to groups receiving cilostazol (n=17), pentoxifylline (n=17) or placebo (n=16). Patients given either cilostazol or pentoxifylline showed a significant improvements in maximal walking distance compared with the placebo group (34 m and 33 m respectively, compared with 5 m; both P<0.05). Neither cilostazol nor pentoxifylline increased the ankle-brachial index after treatment. Circulating VEGF levels were increased (from 116+/-29 to 169+/-45 pg/ml; P=0.002), and the levels of VEGF were correlated significantly with exercise tolerance in a positive direction (r=0.88, P=0.004), in those patients treated with cilostazol that did not have diabetes mellitus. In contrast, VEGF levels remained stable after the administration of pentoxifylline. These findings suggest that VEGF may contribute to the cilostazol-related improvement in exercise tolerance in non-diabetic patients. However, pentoxifylline did not affect VEGF levels, although a similar improvement in maximal walking distance was achieved. Thus the mechanisms involved in the pentoxifylline-treated group were different from those in the cilostazol-treated group, and require further study.

Effect of hydroxyzine on the transport of etoposide in rat small intestine.

Etoposide, an anti-neoplastic agent and a substrate of P-glycoprotein (P-gp), exhibits variable oral bioavailability. P-gp, the multidrug resistance gene (mdr1) product, has been considered as an absorption barrier against intestinal drug absorption. Terfenadine, an antihistamine, has been shown to be a P-gp inhibitor. The current study was designed to assess the effect of hydroxyzine, an antihistamine, on the transport of etoposide in the small intestine. Everted rat gut sacs were used to determine the absorption and exsorption of etoposide under different conditions, as rhodamine 123 was chosen to evaluate the role of P-gp in the drug interaction. The results showed that the transport of etoposide was significantly increased from the luminal site to the serosal site in the jejunum by 2- and 4-fold after 90 min in the presence of hydroxyzine and quinidine, respectively. A similar trend was observed in the ileal sacs. This in vitro exsorption study also demonstrated that hydroxyzine could reduce the efflux of etoposide to the luminal site in either jejunum or ileum. The effect of hydroxyzine on the pharmacokinetics of etoposide differed by the in vivo route of administration, thus assuming clinical importance for chemotherapeutic treatment.

Distension of urinary bladder induces exaggerated coronary constriction in smokers with early atherosclerosis.

Distension of the urinary bladder causes an increase in efferent sympathetic activity, which can precipitate myocardial ischemia. Smoking has been shown to modulate activities of afferent nerves from the distended urinary bladder and to impair endothelial function in response to sympathetic activation. To assess the effect of bladder distension on coronary dynamics in smokers, we measured epicardial and microvascular responses in 24 patients with early atherosclerosis (< 50% diameter stenosis). Patients were classified into habitual smokers (group 1, n = 14) and nonsmokers (group 2, n = 10). Habitual smokers were randomized into two subgroups on the basis of the use of doxazosin, as follows: subgroup 1A (n = 7), without administration of doxazosin before catheterization; subgroup 1B (n = 7), with dosing doxazosin. In response to bladder distension (mean intravesical pressure 21.5 mmHg), bladder distension significantly decreased coronary diameter at the stenotic segments, coronary blood flow, and increased coronary resistance compared with baseline values, in subgroup 1A patients. In subgroup 1B patients during bladder distension, coronary diameter, coronary blood flow, and coronary resistance did not show significant changes compared with baseline values. There were significant differences of coronary diameter at the stenotic segments, coronary blood flow, and of changes of coronary vascular resistance between subgroup 1A and group 2 during bladder distension, despite similar changes in rate-pressure product. The present study showed that urinary bladder distension caused an abnormal vasomotor response of epicardial vasoconstriction and a concomitant increased coronary resistance, which leads to reduction in coronary blood flow in patients with early atherosclerosis. Smoking may further impair the response, implying that smoking has exaggerated response to sympathetic stimulation of conduit and resistance vessels. The abnormal response was abolished by pretreated administration of doxazosin, suggesting that the involved mechanisms are related to alpha(1)-adrenoceptors.

Cardioprotective effects of 17 beta-estradiol produced by activation ofmitochondrial ATP-sensitive K(+)Channels in canine hearts.

We have previously demonstrated the effects of estrogen on modulation of myocardial ATP-sensitive K(+)(K(ATP)) channel. Previous studies have demonstrated that activation of mitochondrial K(ATP)channel is a major contributor of ischemic cardioprotection. The purpose of the present study was to investigate the role of K(ATP)channel in estrogen-induced myocardial protection after ischemia/reperfusion in dogs. Anaesthetized dogs were subjected to 60 min of left anterior descending coronary artery occlusion followed by 2 h of reperfusion. In a first study to characterize effects of sex and the dose-response profile of estrogen on infarct size, the drug was intravenously administered at 10 or 20 microg/kg. In a second study to investigate the cardioprotective mechanisms of estrogen, vehicle, preconditioning or 17 beta -estradiol (10 microg/kg) was given, beginning 15 min prior to the 60 min occlusion period in the presence or absence of 5-hydroxydecanoate (5-HD). In the first study, administration of 17 beta -estradiol resulted in a significant, dose-dependent limitation of infarct size. Estrogen administration provided myocardial protection of similar magnitude in both males and females. In the second study, infarct size in control animals averaged 39+/-5% of the risk region, compared with 14+/-5% of the risk region in estrogen-treated dogs and 6+/-5% of the risk region in preconditioning dogs (both P<0.0001 v controls). Pretreatment with 5-HD completely abolished preconditioning- and estrogen-induced cardioprotection. Estrogen limits myocardial infarction size resulting from coronary artery occlusion and reperfusion in a dose-dependent fashion, irrespective of gender difference. The infarct size-limiting effect of estrogen++ was abolished by 5-HD, suggesting that the cardioprotective effect of estrogen may result from activation of myocardial mitochondrial K(ATP)channels.

Regression of ventricular repolarisation inhomogeneity after aortic bileaflet valve replacement in patients with aortic stenosis.

BACKGROUND: Aortic valve replacement relieves mechanical outflow obstruction in patients with aortic stenosis. However, there is limited information on whether aortic valve replacement can provide regression of ventricular repolarisation inhomogeneity. OBJECTIVES: To determine whether aortic valve replacement can provide regression of ventricular repolarisation inhomogeneity in patients with aortic stenosis after bileaflet aortic valve replacement. METHODS: We studied the changes of electrocardiographic QT or QTc intervals and QT or QTc dispersions of 71 patients with severe aortic stenosis and angiographically insignificant coronary lesions (<50% in diameter) before and after valve replacement (6+/-3 days after operation). Seventy-one healthy control subjects, matched for age and sex, served as control subjects. Twelve-lead electrocardiograms and echocardiographic examinations were measured before and after surgery. The QT interval was corrected for heart rate using the standard Bazett formula. QT dispersion was defined as the difference between maximal and minimal QT interval measurements occurring among any of the 12 leads on a standard electrocardiogram. QTc dispersion was calculated in a manner similar to QT dispersion. No subject had fewer than nine measurable leads. RESULTS: Left ventricular systolic blood pressure, pressure gradient across aortic valve, left ventricular mass index, and systolic wall stress were significantly reduced after valve replacement compared with before valve replacement. The QT interval significantly decreased from 425+/-38 ms to 398+/-32 ms after replacement (P<0.0001). The QTc dispersion significantly decreased from 62+/-25 ms to 32+/-13 ms after replacement (P<0.0001). The value of QT or QTc dispersion after replacement was similar to that in controls. Univariate analysis revealed that QTc dispersion was significantly only correlated with left ventricular mass index (r=0.236, P=0.05). Multivariate analysis revealed that the best predictor of QTc dispersion was sex and left ventricular mass index (P=0.008 and 0.005, respectively). CONCLUSIONS: Our study demonstrated a favorable consequence of aortic valve replacement distinct from hemodynamic improvement. Patients with aortic stenosis before valve replacement have abnormal prolonged QT or QTc intervals and increased QT or QTc dispersions. After successful valve replacement left ventricular mass index regressed and QT or QTc intervals and QT or QTc dispersions were normalized. These findings warrant further investigation in a large trial and long-term follow-up for clinical implications.

Effect of estrogen on ventricular repolarization in menopausal patients with syndrome X and effects of nicorandil.

Syndrome X may exhibit myocardial ischemia and is associated with estrogen deficiency. We sought to assess the possible role of estrogen in modulating the characteristics of ventricular repolarization by measurement of QT interval and QT dispersion in patients with syndrome X. We prospectively used 12-lead electrocardiograms and echocardiograms to study 52 consecutive menopausal patients with syndrome X (group subdivided into subgroup 1a, 32 patients who received nicorandil, an adenosine triphosphate-sensitive potassium ion channel opener; subgroup 1b, 20 patients without dosing nicorandil). For comparisons, a control group consisted of age-matched and echocardiographic left ventricular mass index-matched 20 healthy menopausal women. Baseline QT intervals and QT dispersion were similar between the 2 groups (subgroup 1a and controls). After administration of estrogen, there was significant prolongation of maximal QTc intervals and reduction in QT or QTc dispersion compared with baseline in patients with syndrome X. The changes returned to baseline after nicorandil administration. Control subjects had no changes with administration of estrogen. Thus, estrogen modulates characteristics of ventricular repolarization, which appears to be mediated by blocking adenosine triphosphate-sensitive potassium ion channel. The effects of estrogen on QT intervals may be different between menopausal women with or without syndrome X.

Functional characterization of a human purine-selective, Na+-dependent nucleoside transporter (hSPNT1) in a mammalian expression system.

Nucleosides and nucleoside analogs are actively transported in the human kidney. With the recent cloning of a purine-selective, Na+-dependent, nucleoside transporter (hSPNT1, also termed hCNT2) from human kidney, it is now possible to study the interaction of nucleosides and nucleoside analogs with this transport protein and gain a more detailed knowledge of the underlying mechanisms of nucleoside transport in the human kidney. In this study we examined the substrate selectivity of hSPNT1 for nucleosides and nucleoside analogs. We determined that the naturally occurring nucleosides adenosine, inosine, and uridine are substrates for this carrier, whereas thymidine is not. The nucleoside analogs (0.5 mM) 2', 3'-dideoxyadenosine; 2',3'-dideoxyinosine; and 2-chloro-2'deoxyadenosine (2CdA), significantly inhibited the uptake of [3H]inosine in HeLa cells transiently transfected with hSPNT1. However, there was no significant Na+-dependent uptake of [3H]2', 3'-dideoxyinosine or [3H]2CdA in the transfected cells, suggesting that these nucleoside analogs are not permeants of hSPNT1. Interestingly, 2CdA was considerably less potent in inhibiting [3H]inosine uptake in HeLa cells expressing hSPNT1 than in cells expressing the rat homolog rSPNT (IC50 = 371 microM versus 13.8 microM), suggesting that there may be notable species differences in the kinetic interactions of some nucleoside analogs with purine- selective nucleoside transporters.

Na(+)-dependent purine nucleoside transporter from human kidney: cloning and functional characterization.

Many purine nucleosides and their analogs are actively transported in the kidney. Using homology cloning strategies and reverse transcriptase-polymerase chain reactions, we isolated a cDNA encoding a Na(+)-dependent nucleoside transporter, hSPNT1, from human kidney. Functional expression in Xenopus laevis oocytes identified hSPNT1 as a Na(+)-dependent nucleoside transporter that selectively transports purine nucleosides but also transports uridine. The Michaelis constant (K(m)) of uridine (80 microM) in interacting with hSPNT1 was substantially higher than that of inosine (4.5 microM). hSPNT1 (658 amino acids) is 81% identical to the previously cloned rat Na(+)-nucleoside transporter, SPNT, but differs markedly from SPNT in terms of its primary structure in the NH2 terminus. In addition, an Alu repetitive element (approximately 282 bp) is present in the 3'-untranslated region of the hSPNT1 cDNA. Northern analysis revealed that multiple transcripts of hSPNT1 are widely distributed in human tissues including human kidney. In contrast, rat SPNT transcripts are absent in kidney and highly localized to liver and intestine. The hSPNT1 gene was localized to chromosome 15. This is the first demonstration of a purine nucleoside transporter in human kidney.

Left atrial spontaneous echo contrast in asymptomatic patients with a mechanical valve prosthesis.

BACKGROUND: Valve thromboembolism may be a fatal complication of mechanical valve prosthesis if detected late. Spontaneous echo contrast (SEC) is a well-documented prothrombotic phenomenon; here we report it in asymptomatic patients with a mechanical valve prosthesis. METHODS: Ninety-two asymptomatic patients with a mechanical valve prosthesis for underlying rheumatic heart disease underwent transesophageal echocardiography. Appendage area, peak filling and emptying velocities of the left atrial appendage, and the presence or absence of SEC and thrombi were determined. The results of 56 patients without SEC or thrombi (group I) were compared with those of 24 patients with SEC and no thrombi (group II) and 12 patients with thrombi (group III). RESULTS: Spontaneous echo contrast was present in 39% of the asymptomatic patients with a mechanical valve prosthesis. Although 12 patients had cardiac thrombi, including valve thrombi in 4, no patients presented symptoms. Anticoagulant therapy had no significant association with SEC and atrial thrombi. There was a significantly greater prevalence of atrial fibrillation and mitral prosthesis in groups II and III than in group I. Two patterns of left atrial appendage flow were identified: one was organized biphasic flow with peak filling velocities of 41.2 +/- 17.2 cm/s and emptying velocities of 40.5 +/- 17.5 cm/s. The other showed irregular, very low peak filling velocities (104 +/- 11.5 cm/s) and emptying velocities (12.3 +/- 13.1 cm/s). The former flow pattern was associated with sinus rhythm and the latter form was associated with atrial fibrillation. CONCLUSIONS: There was a relatively high prevalence of SEC and thrombi in patients with a mechanical valve prosthesis. Patients with a valve prosthesis may not have clinical symptoms. Anticoagulation intensity was not associated with the occurrence of SEC and thrombi. Patients with the mitral valve prosthesis and atrial fibrillation were identified as a high-risk of subgroup for the development of SEC and thrombi.