Correlation between maximum heart distance and thoracic diameter changes and diaphragmatic descent in left-sided breast cancer patients during deep inspiration breath-hold (DIBH).

BACKGROUND: Cardioprotection is valued in radiotherapy for patients with left-sided breast cancer. Deep inspiration breath-hold (DIBH) technique can achieve cardioprotection well. However, during DIBH, the extent to which the heart enters the radiation field is affected by the movement of the thorax and diaphragm. The aim of this study was to analyze the correlation between the maximum distance of the heart entering the field (maximum heart distance, MHD) and thoracic diameter changes and diaphragmatic descent in left-sided breast cancer patients during DIBH. PATIENTS AND METHODS: Ninety-eight patients with left-sided breast cancer were included in this retrospective study. They performed simulation in Sentinel-guided DIBH, and two sets of CT images were collected under both free breathing (FB) and DIBH, and diaphragm positions, anteroposterior thoracic diameter (ATD), transverse thoracic diameter (TTD), gating window level (GWL), and MHD were measured, and the change (Δ) of each parameter in DIBH relative to that in FB were calculated. Pearson or Spearman test were used to analyze the correlation between ΔMHD and the changes in other parameters. RESULTS: For all patients with DIBH, the average of ΔMHD was -8.3 mm, and the average of ΔATD and ΔTTD were 11.0 and 8.6 mm, and the median of both left diaphragmatic descent (LDD) and right diaphragmatic descent (RDD) were 35.0 mm, and the median of GWL was 11.1 mm. The correlation coefficients between MHD decrease (ΔMHD) and LDD, RDD, and ΔTTD were -0.430 (p = 0.000), -0.592 (p = 0.000) and 0.208 (p = 0.040), respectively, but not significantly correlated with ΔATD or GWL. CONCLUSIONS: The MHD decrease showed a moderate correlation with diaphragmatic descent In Sentinel-guided DIBH for patients with left-sided breast cancer, while there was a weak or no correlation with thoracic diameter changes or GWL. Abdominal breathing can lower diaphragm more and may be more beneficial to the heart stay away from tangential field.

The G314S KCNQ1 mutation exerts a dominant-negative effect on expression of KCNQ1 channels in oocytes.

Congenital long QT syndrome is a cardiac disorder characterized by prolongation of QT interval on the surface ECG associated with syncopal attacks and a high risk of sudden death. Mutations in the voltage-gated potassium channel subunit KCNQ1 induce the most common form of long QT syndrome (LQT1). We previously identified a hot spot mutation G314S located within the pore region of the KCNQ1 ion channel in a Chinese family with long QT syndrome. In the present study, we used oocyte expression of the KCNQ1 polypeptide to study the effects of the G314S mutation on channel properties. The results of electrophysiological studies indicate G314S, co-expressed with KCNE1 was unable to assemble to form active channel. G314S, co-expressed with WT KCNQ1 and KCNE1, suppressed I(ks) currents in a dominant-negative manner, which is consistent with long QT syndrome in the members of the Chinese family carrying G314S KCNQ1 mutation.

Congenital long QT syndrome caused by the F275S KCNQ1 mutation: mechanism of impaired channel function.

Congenital long QT syndrome is characterized by a prolongation of ventricular repolarization and recurrent episodes of life-threatening ventricular tachyarrhythmias, often leading to sudden death. We previously identified a missense mutation F275S located within the S5 transmembrane domain of the KCNQ1 ion channel in a Chinese family with long QT syndrome. We used oocyte expression of the KCNQ1 polypeptide to study the effects of the F275S mutation on channel properties. Expression of the F275 mutant, or co-expression with the wild-type S275 polypeptide, significantly decreased channel current amplitudes. Moreover, the F275S substitution decreased the rates of channel activation and deactivation. In transfected HEK293 cells fluorescence microscopy revealed that the F275S mutation perturbed the subcelluar localization of the ion channel. These results indicate that the F275S KCNQ1 mutation leads to impaired polypeptide trafficking that in turn leads to reduction of channel ion currents and altered gating kinetics.

Investigations of the cytotoxicity of epigallocatechin-3-gallate against PC-3 cells in the presence of Cd2+ in vitro.

The epidemiological studies and recent data have provided convinced evidence that green tea and its major constituent epigallocatechin gallate (EGCG) might have the potential to lower the risk of cancers in humans. Metal ions, such as zinc and cadmium, which are necessary to our health, are important factors inducing many diseases including prostate cancer in the condition of absence or excess. EGCG can satisfactorily exhibit complex chemistry with metal ions because of multiple hydroxyl states, which in turn changes their bioactivities and metabolism pathways. This paper presents the results of an investigation of the cytotoxicity of EGCG against PC-3 prostate cancer cells in the presence and absence of Cd2+ in vitro. The results showed that both EGCG and Cd2+ suppressed viability and clonegenecity of PC-3 cells, and the suppression effect was enhanced when EGCG added with Cd2+. Although Cd2+ up-regulated the 67 kDa laminin receptor (67LR), which is a migration-associated protein, the cell migration ability was not significantly increased after each treatment. We also found that EGCG and Cd2+ directly interacted with mitochondrial, and the mixture of EGCG and Cd2+ (EGCG+Cd2+) significantly caused loss of the mitochondrial membrane potential, decrease of the ATP content and activation of caspase-9 compared with EGCG treated alone. Taken together, these findings suggest that Cd2+ enhanced the cytotoxicity of EGCG to PC-3 cells by up-regulating the 67LR and the mitochondria-mediated apoptosis pathway.

[Gene mutation in secundum atrial septal defect: analysis of a Chinese family with 3 patients].

OBJECTIVE: To study the gene mutations of homeobox transcription factor (CSX/NKX(2.5)) associated with a Chinese family with secundum atrial septal defect (ASD). METHODS: Polymerase chain reaction and DNA sequencing were used to check all the members in the family with ASD, including 3 ASD patients and 10 non-patients, with the proband from Hunan province; and single strand conformation polymorphism analysis was used to check 126 normal control people for detecting the mutations of CSX/NKX(2.5) gene. RESULTS: Three heterozygous mutation [G270A (Glu32Lys), G378A (Glu68Lys) and G390A (Glu72Lys)] were identified in the CSX/NKX(2.5) gene of the ASD patients. However, the other members in the family with ASD patients and the controls did not have such gene mutations. CONCLUSION: The above mentioned mutations of CSX/NKX(2.5) gene identified in a Chinese family may be one of the secundum ASD etiologic causes.

Comparison of effects of epigallocatechin-3-gallate on hypoxia injury to human umbilical vein, RF/6A, and ECV304 cells induced by Na(2)S(2)O(4).

Hypoxia is related to the etiology of numerous pathological disease states, such as the formation of tumors or diverse retinopathies. Epigallocatechin-3-gallate (EGCG), a potent polyphenolic antioxidant and antiangiogenic compound found in green tea, has been shown to suppress the growth of blood vessels necessary for the growth of tumors and the induction of retinopathies. However, only a few studies have been carried focusing on the protective effects of EGCG on hypoxia-induced injury of cultured endothelial cells. The present study investigated the effects of EGCG on Na(2)S(2)O(4)-induced hypoxic injury in three types of cultured endothelial cells, primary isolates of normal human umbilical vein endothelial cells (HUVECs), and two transformed endothelial cells lines, RF/6A and ECV304. Our results indicated that Na(2)S(2)O(4) inhibited the growth of HUVE, RF/6A, and ECV304 cells in a dose-dependent manner; EGCG also exerted inhibitory effects on the growth of the three cell types, but the toxicity of EGCG to HUVECs was less than to RF/6A and ECV304 cells. The viability of HUVE, RF/6A, and ECV304 cells treated with EGGC were the lowest at 24, 24, and 36 h, respectively, and the IC(50) of EGCG were 420 +/- 8.0, 125 +/- 7.1, and 75 +/- 5.1 microM, respectively. Furthermore, EGCG, an efficient nontoxic agent, protected all three cell types from Na(2)S(2)O(4)-induced hypoxia injury, providing partial protection from hypoxia-induced injury in normal endothelial cells at 100, 30, and 10 microM for HUVE, RF/6A, and ECV304 cells, respectively.

[Gene (SCN5A) mutation analysis of a Chinese family with Brugada syndrome].

OBJECTIVE: To analyze the gene mutations on the cardiac sodium channel gene SCN5A in a Chinese family with Brugada syndrome. METHOD: Polymerase chain reaction and DNA sequencing were used to screen gene mutations on the cardiac sodium channel gene SCN5A in all family members of a Chinese pedigree with Brugada syndrome, single strand conformation polymorphism analysis were performed in 136 normal controls to detect the mutations of SCN5A gene. RESULT: Two heterozygosis mutations, which include a missense mutation (Y1494N) and a same sense mutation (A29A), were identified on SCN5A gene in the proband with Brugada syndrome and these mutations were not detected in other family members with Brugada syndrome and in controls. CONCLUSION: We detected a reported polymorphism site (A29A) and a novel missense mutation (Y1494N) on SCN5A in this Chinese family with Brugada syndrome.

[Study on novel mutations of MEF2A gene in Chinese patients with coronary artery disease].

OBJECTIVE: To explore the mutations of MEF2A gene in Chinese patients with coronary artery disease(CAD). METHODS: With polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) and DNA direct sequencing, the mutation analysis of exon 11 of MEF2A gene was performed to 156 patients with CAD and 93 normal controls. RESULTS: By DNA sequence analyzing the samples of abnormal mobility shift of SSCP, the MEF2A gene mutations were found in three patients with CAD. One of mutations was 147130(C>A)(P431Q), and the second one was 21 bases deletion(147108-147128) which was leading to the absence of 7 amino acids (424QQQQQQQ430), and the third was 147191(G>T). Three mutations were all found in one patient, but meanwhile 21 bases deletion was found in the other two patients. CONCLUSION: Mutations in exon 11 of MEF2A gene exist in the patients with CAD, and the mutations may be pathological.

Inhibitory effect of rhynchophylline on human ether-a-go-go related gene channel.

We studied the effects of Chinese traditional medicine rhynchophylline (Rhy) on human ether-a-go-go related gene (HERG) channel and characterized the electrophysiological properties of Rhy's pharmacological effect on HERG channel using Xenopus oocytes. Xenopus oocytes were injected with either 23 nl (5.75 ng) HERG cRNA or 23 nl distilled water. Xenopus oocytes were randomly assigned to receive one of the following different concentrations of Rhy: (1) control, (2)10 mumol/L Rhy, (3)100 mumol/L Rhy, (4) 500 mumol/L Rhy, (5) 1 000 mumol/L Rhy, (6) 10 000 mumol/L Rhy. Cell currents were recorded in oocytes. The peak tail currents of HERG channel were inhibited by Rhy. The inhibition was in a dose-dependent manner [IC(50)=(773.4 +/- 42.5) mumol/L]. Experiment with 100 mumol/L Rhy indicated that the degree of HERG blockade showed some voltage dependence (within -40 mV to -20 mV ). Kinetic analyses revealed that Rhy decreased the rate of channel activation. The findings indicate that Rhy inhibits HERG encoded potassium channels. It may underline the molecular mechanism of myocardial electrophysiological characteristics associated with this drug.

[Mutation analysis of a Chinese family with inherited long QT syndrome].

OBJECTIVE: To identify the mutation of a Chinese family with inherited long QT syndrome(LQTS). METHODS: The disease-causing gene was tentatively determined in light of the clinical manifestations and electrophysiological properties, and then polymerase chain reaction and DNA sequencing were used for screening and identifying mutation. RESULTS: A missense mutation G940A(G314S) in the KCNQ1 gene was identified, which was the 'hot spot' of long QT syndrome mutation. CONCLUSION: The mutation that is involved with long QT syndrome in Chinese patients is the same as that in the European, American and Japanese patients.

[Relationship between congenital long QT syndrome and Brugada syndrome gene mutation].

OBJECTIVE: To investigate the molecular pathology in families with long QT syndrome (LQTS) including Jervell-Longe-Nielsen syndrome (JLNS) and Romano-ward syndrome (RWS) and Brugada syndrome (BS) in Chinese population. METHODS: Polymerase chain reaction and DNA sequencing were used to screen for KCNQ1, KCNH2, KCNE1, and SCN5A mutation. RESULTS: We identified a novel mutation N1774S in the SCN5A gene of the BS family, a novel mutation G314S in a RWS family which had also been found in Europe, North America, and Japan, and a single nucleotide polymorphisms (SNPs) G643S in the KCNQ1 of the JLNS family. In this JLNS family, another heterozygous novel mutation in exon 2a was found in KCNQ1 of the patients. CONCLUSION: New mutations were found in our experiment, which expand the spectrum of KCNQ1 and SCN5A mutations that cause LQTS and BS.

[PCR site-directed mutagenesis of long QT syndrome KCNQ1 gene in vitro].

To study PCR site-directed mutagenesis of long QT syndrome KCNQ1 gene in vitro. The site-directed mutagenesis of LQTS gene KCNQ1 was made by PCR. Two sets of primers were designed according to the sequence of KCNQ1 cDNA, and mismatch was introduced into primers. Mutagenesis was performed in a three-step PCR. The amplified fragments from the third PCR which contained the mutation site were subcloned into the T-vecor PCR2.1. Then the fragments containing the mutation site was obtained from PCR2.1 with restriction enzyme digestion and was inserted into the same restriction site of pIRES2-EGFP-KCNQ1. With Effectene Transfection Reagent, pIRES(2)-EGFP-KCNQ1 was transfected into HEK293 cell. The sequencing analysis showed that the mutation site was correct. Mutation from T to C in 934 site of KCNQ1 cDNA was found. Under the fluorescence microscope, the green fluorescence was spread in the transfected HEK293 cell, meaning the pIRES(2)-EGFP-KCNQ1 containing the mutation site was expressed correctly.

Effect of laminin tyrosine-isoleucine-glycine-serine-arginine peptide on the growth of human prostate cancer (PC-3) cells in vitro.

The laminin tyrosine-isoleucine-glycine-serine-arginine (YIGSR) peptide, corresponding to the 929-933 sequence of beta1 chain, is known to inhibit tumor growth and metastasis. In the present study, we observed that YIGSR not only inhibited the growth and migration of prostate cancer cells in a dose-dependent manner but also decreased mitochondrial membrane potential, inhibited ATP synthesis and increased caspase-9 activity. Investigation into the interaction of YIGSR with 67LR, the receptor for laminin and polyphenol (-) epigallocatechin-3-gallate (EGCG) employing MVD (Molegro Virtual Docker, an integrated platform for predicting protein ligand interactions), revealed that the binding site of YIGSR was the same as that of EGCG that explains as to why YIGSR is able to inhibit the cytotoxicity of EGCG against PC-3 cells.

Epigallocatechin-3-gallate affects the growth of LNCaP cells via membrane fluidity and distribution of cellular zinc.

OBJECTIVE: To evaluate effects of epigallocatechin-3-gallate (EGCG) on the viability, membrane properties, and zinc distribution, with and without the presence of Zn(2+), in human prostate carcinoma LNCaP cells. METHODS: We examined changes in cellular morphology and membrane fluidity of LNCaP cells, distribution of cellular zinc, and the incorporated portion of EGCG after treatments with EGCG, Zn(2+), and EGCG+Zn(2+). RESULTS: We observed an alteration in cellular morphology and a decrease in membrane fluidity of LNCaP cells after treatment with EGCG or Zn(2+). The proportion of EGCG incorporated into liposomes treated with the mixture of EGCG and Zn(2+) at the ratio of 1:1 was 90.57%, which was significantly higher than that treated with EGCG alone (30.33%). Electron spin resonance (ESR) studies and determination of fatty acids showed that the effects of EGCG on the membrane fluidity of LNCaP were decreased by Zn(2+). EGCG accelerated the accumulation of zinc in the mitochondria and cytosol as observed by atomic absorption spectrometer. CONCLUSION: These results show that EGCG interacted with cell membrane, decreased the membrane fluidity of LNCaP cells, and accelerated zinc accumulation in the mitochondria and cytosol, which could be the mechanism by which EGCG inhibits proliferation of LNCaP cells. In addition, high concentrations of Zn(2+) could attenuate the actions elicited by EGCG.

[Growth inhibition of prostate cancer cells by epigallocatechin-3-gallate in the presence of Zn2+ in vitro].

In this paper, the cytotoxicity of EGCG against PC-3 prostate cancer cells and its molecular mechanism in the presence and absence of Zn2+ in vitro were investigated. The results showed that both EGCG and Zn2+ suppressed clonegenecity of PC-3 cells, and the suppression effect was enhanced in the coexist system of EGCG and Zn2+. MMP-9 is thought to play a significant role in cancer cell migration and invasion. In the present paper, the results showed that EGCG suppressed the activity of MMP-9 in PC-3 cells in the presence of Zn2+, as a result, migration ability of the cells was significantly decreased.

Free Zn(2+) enhances inhibitory effects of EGCG on the growth of PC-3 cells.

Epigallocatechin-3-gallate (EGCG), a major component of green tea, has both preventive and therapeutic beneficial actions in prostate cancer. In the present study, we compared the growth inhibitory effects and the antioxidant and ability to modify cell membrane permeation of zinc-EGCG complex and Zn2+/EGCG mixture on androgen-insensitive prostate cancer (PC-3) cells. It was noted that free Zn2+ enhanced the growth inhibitory effects of EGCG on PC-3 cells at 160 micromol/L concentration,whereas zinc-EGCG complex was ineffective. EGCG showed potent free radical scavenging ability in the presence of Zn2+. EGCG in the presence of Zn2+ was more effective than EGCG alone in enhancing the permeability of the cell membrane, whereas zinc-EGCG complex had no effect on PC-3 cell membrane permeability. These results indicate that though Zn2+ enhanced the action of EGCG on PC-3 cells, zinc-EGCG complex is highly unlikely to be formed in the presence of Zn2+ and EGCG to explain the potentiating action of Zn2+ on the growth inhibitory property of EGCG on PC-3 cells.