Antimicrobial activity of the volatile compound 3,5-dichloro-4-methoxybenzaldehyde, produced by the mushroom Porostereum spadiceum, against plant-pathogenic bacteria and fungi.

AIMS: In this study, volatile compounds released from mycelia of some aromatic mushrooms were investigated for their inhibitory activity against plant-pathogenic bacteria and fungi. METHODS AND RESULTS: A screening revealed that volatile compounds from mycelia of Porostereum spadiceum remarkably inhibited the colony formation of plant-pathogenic bacteria, including Clavibacter michiganensis subsp. michiganensis and Ralstonia solanacearum while also inhibiting the conidial germination of plant-pathogenic fungi including Alternaria brassicicola and Colletotrichum orbiculare. The volatile compounds were isolated from the culture filtrate of P. spadiceum, and 3,4-dichloro-4-methoxybenzaldehyde (DCMB) was identified as a major compound. DCMB significantly inhibited bacterial colonization at 10 µg ml-1 and fungal conidial germination at 0·1-1 µg ml-1 as a vapour. CONCLUSIONS: This is the first report on the production of the volatile compound DCMB by P. spadiceum and on the antimicrobial activity of DCMB against plant-pathogenic bacteria and fungi at low concentrations. It may be possible to use the compound as an agent for protecting crops from bacterial and fungal diseases during cultivation and storage. SIGNIFICANCE AND IMPACT OF THE STUDY: This study provides an understanding of antimicrobial activity of the mushroom volatile compound that may be useful as a novel biological control agent for protecting various plant diseases.

MRI study of atherosclerotic plaque progression using ultrasmall superparamagnetic iron oxide in Watanabe heritable hyperlipidemic rabbits.

OBJECTIVE: The purpose of this study was to evaluate plaque progression by using MRI with ultrasmall superparamagnetic iron oxide (USPIO) and by histopathological studies. METHODS: We divided 12 Watanabe heritable hyperlipidemic (WHHL) rabbits into 4 groups based on their age (3, 9, 14 and 26 months) and injected them intravenously with 0.8 mmol (Fe) kg(-1) of USPIO (size, 32 nm; concentration, 15 mg dl(-1)). On the fifth post-injection day, they were again given an intravenous injection with 40 µmol kg(-1) of the same USPIO, and MR angiography (MRA) was performed. The signal-to-noise ratio (SNR) in regions of interest in the wall of the upper abdominal aorta was calculated on coronal images. Specimens from the same level of the aorta were subjected to iron staining and RAM-11 immunostaining and used for histopathological study. For statistical analysis of the MRA and histopathological findings, we used analysis of variance [Tukey's honest significant difference (HSD) test]. RESULTS: In 9-month-old rabbits, the SNR was significantly lower than in rabbits of the other ages (p < 0.01), and the area of RAM-11 (DAKO Corporation, Glostrup, Denmark) and iron uptake in the aortic wall was significantly larger (RAM-11, p < 0.01; iron, p < 0.05). These areas were the smallest in 3-month-old rabbits. CONCLUSION: Histopathologically, the number of macrophages was the greatest in 9-month-old rabbits. Our findings indicate that the SNR on MRI scans reflects the number of macrophages in the aortic wall of WHHL rabbits. ADVANCES IN KNOWLEDGE: USPIO-enhanced MRI visualized the accumulation of macrophages in early atherosclerotic plaques of WHHL rabbits in the course of natural progression.

Effect of ageing on healing of bilateral mandibular condyle fractures in a rat model.

To examine the hypothesis that conservative treatment is applicable to younger patients with bilateral mandibular condylar fractures, we studied the effect of ageing on the healing of bilateral mandibular condylar fractures in a rat model. Male Sprague-Dawley rats aged 3, 6, and 36 weeks (n=25/cohort, total n=75) were divided into a fracture group (n=12) and a sham control group (n=12); one rat from each cohort was used as a normal unoperated control. Cell proliferation was evaluated using the bromodeoxyuridine (BrdU) labelling index (LI). Osteochondrogenesis was assessed by the expression of Indian hedgehog (Ihh), type X collagen, and osteocalcin in the condylar head. Condylar fracture healing was found to be delayed by ageing. BrdU LI values in the fracture groups were higher in younger rats than in older rats at 8 weeks after fracture. The number of Ihh-positive cells in the fracture groups increased significantly up to 2 weeks after fracture, and then gradually decreased until 8 weeks after fracture. The findings of this study support the clinical concept of conservative treatment of bilateral condylar fractures in younger patients, but functional issues regarding ramus height and its consequences on occlusion have not been tested in this study.

Anti-tumour effects of transcatheter arterial embolisation administered in combination with thalidomide in a rabbit VX2 liver tumour model.

OBJECTIVE: Using a liver tumour model we investigated whether thalidomide enhances the anti-tumour effect of transcatheter arterial embolisation (TAE). METHOD: First, the viability of VX2 tumour cells co-cultured with thalidomide in a 21% and 1% O(2) atmosphere was assessed by 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. Second, we randomly assigned 20 rabbits bearing VX2 liver tumours to 4 groups: Group 1 (thalidomide plus TAE), Group 2 (TAE only), Group 3 (thalidomide only) and Group 4 (control). Thalidomide was orally administered for 5 days. The anti-tumour effects were assessed by the tumour proliferation rate using MRI and by immunohistochemical analysis of the area of intratumoural vessels. Analysis of variance and Tukey's honestly significant difference test were used for statistical analysis. RESULTS: The viability of cells grown under hypoxic and normal conditions was not significantly different, nor was there a difference among the four groups. The tumour size increased by 55.9±29.3% in Group 1, 250.6±73.3% in Group 2, 355.2±51.7% in Group 3 and 424.7±110.7% in Group 4; the difference between Group 1 and the other three groups was significant. The area of intratumour vessels in specimens was 0.22±0.28% in Group 1, 0.42±0.29% in Group 2, 1.44±1.00% in Group 3 and 6.00±2.17% in Group 4; the difference between Group 1 and the other groups was statistically significant, as was the difference between Groups 3 and 4. CONCLUSION: Thalidomide used in combination with TAE enhanced anti-tumour effects in rabbits bearing VX2 liver tumours.

A combination of cisplatin-eluting gelatin microspheres and flavopiridol enhances anti-tumour effects in a rabbit VX2 liver tumour model.

The aim of this study was to investigate whether the combination of cisplatin-eluting gelatin microspheres (GMSs) and flavopiridol enhances anti-tumour effects in a rabbit VX2 liver tumour model. Tumour-bearing rabbits (n = 21) were divided into five groups and infused from the proper hepatic artery. Group 1 (n = 5) received cisplatin-eluting GMSs (1 mg kg(-1)) and flavopiridol (3 mg kg(-1)), group 2 (n = 5) cisplatin-eluting GMSs alone (1 mg kg(-1)), Group 3 (n = 5) flavopiridol (3 mg kg(-1)), Group 4 (n = 3) GMSs alone (1 mg kg(-1)), and Group 5 (n = 3) was the control group receiving physiological saline (1 ml kg(-1)). On days 0 and 7 after procedures the liver tumour volume was measured using a horizontal open MRI system and the relative tumour volume growth rates for 7 days after treatment were calculated. On T(1) weighted images, the tumours were visualised as circular, low-intensity areas just below the liver surface. After treatment, the signals remained similar. The relative tumour volume growth rate for 7 days after treatment was 54.2+/-22.4% in Group 1, 134.1+/-40.1% in Group 2,166.7+/-48.1% in Group 3, 341.8+/-8.6% in Group 4 and 583.1+/-46.9% in Group 5; the growth rate was significantly lower in Group 1 than the other groups (p<0.05). We concluded that in our rabbit model of liver tumours the combination of cisplatin-eluting GMSs and flavopiridol was effective.

Partial functional overlap of the three ras genes in mouse embryonic development.

In mammals, three ras genes, H-ras, N-ras and K-ras, encode homologous but distinct 21-kDa Ras proteins. We examined the in vivo functional relationship of the three ras genes in mouse embryonic development by investigating the phenotypes of mice deficient in one or multiple ras genes. H-ras-/- mice and N-ras-/- mice as well as a substantial proportion of H-ras-/-/N-ras-/- mice expressing only the K-ras gene were viable, while K-ras-/- mice were embryonically lethal, as have been reported previously. N-ras-/-/K-ras+/- mice died neonatally, while H-ras-/-/K-ras-/- embryos died much earlier than K-ras homozygous mutant fetuses. To further investigate the functional relationship of the ras genes in embryonic development, we introduced a human H-ras transgene into single or multiple ras mutant mice and found that the transgene rescued mice, including triple ras mutants, from embryonic lethality in association with correction of thin ventricular walls of the heart in null K-ras mutant mice. In situ hybridization revealed that the expression of the H-ras transgene on embryonic day E13.5 and E15.5 was more intense in major organs, including the heart, than those of endogenous ras genes. We therefore conclude that the functions of the ras genes are partially overlapping in mouse embryonic development.

Reg I-knockout mice reveal its role in regulation of cell growth that is required in generation and maintenance of the villous structure of small intestine.

Reg I (regenerating gene product I) is a growth factor that plays a central role in the generation and regeneration of the gastric mucosal architecture. On the other hand, mouse Reg I mRNA is expressed at the highest levels in the small intestine among the gastrointestinal tissues. In the current study, with the aim to clarify the role of Reg I protein in the small intestine, the temporal and spatial pattern of Reg I expression and the phenotype of Reg I-knockout mice in the tissue were examined. In the wild-type mice, immunohistochemistry localized Reg I protein expression in absorptive cells located in the lower half of the intestinal villi. Reg I expression was undetectable until embryonic day 13 (E13), when the fetal intestine still lacks villous structure; however, it dramatically increased at E17 along with the formation and maturation of the fetal intestinal villi. In the small intestine of the adult Reg I-knockout mice, less densely packed, round-shaped aberrant morphology of the absorptive cells was observed light microscopically, and electron microscopical examination revealed a strikingly loose connection of these cells to the basement membrane. Antiproliferating cell nuclear antigen staining and anti-Ki67 staining demonstrated the marked decrease in the number of proliferating cells in the small intestinal mucosa of the knockout mice. The cell migration speed visualized by one shot labeling of 5-bromodeoxyuridine was significantly slower in the knockout mice. These phenotypes of Reg I-knockout mice emerged, in accordance with the temporal pattern of Reg I expression described above, from E17. Reg I was considered to be a regulator of cell growth that is required to generate and maintain the villous structure of the small intestine.

Feasibility of rapid-sequence 31P magnetic resonance spectroscopy in cardiac patients.

PURPOSE: To determine the clinical feasibility of rapid-sequence phosphorus-31 magnetic resonance spectroscopy (31P-MRS) of the heart with cardiac patients using a 1.5T clinical MR system. MATERIAL AND METHODS: Twenty cardiac patients, i.e. dilated cardiomyopathy (DCM) 13 cases, hypertrophic cardiomyopathy (HCM) 3 cases, hypertensive heart diseases (HHD) 3 cases, and aortic regurgitation (AR) 1 case were examined using rapid cardiac 31P-MRS. Complete three-dimensional localization was performed using a two-dimensional phosphorus chemical-shift imaging sequence in combination with 30-mm axial slice-selective excitation. The rapid-sequence 31P-MRS procedure was phase encoded in arrays of 8 x 8 steps with an average of 4 acquisitions. The total examination time, including proton imaging and shimming, for the rapid cardiac 31P-MRS procedure, ranged from 10 to 15 min, depending on the heart rate. Student's t test was used to compare creatine phosphate (PCr)/adenosine triphosphate (ATP) ratios from the cardiac patients with those of the control subjects (n = 13). RESULTS: The myocardial PCr/ATP ratio obtained by rapid 31P-MRS was significantly lower (P < 0.001) in DCM patients (1.82 +/- 0.33, mean +/- SD), and in patients with global myocardial dysfunction (combined data for 20 patients: 1.89 +/- 0.32) than in normal volunteers (2.96 +/- 0.59). These results are similar to previous studies. CONCLUSION: Rapid-sequence 31P-MRS may be a valid diagnostic tool for patients with cardiac disease.

Long-term results of chronic hemodialysis patients with isolated coronary artery bypass grafting performed by the same surgeon. A comparative study.

BACKGROUND: The aim of this study was to examine the long-term results of isolated coronary artery bypass grafting (CABG) patients who required chronic hemodialysis. METHODS: From May 1990 to June 2000, 23 hemodialysis patients received isolated CABG performed by the same surgeon. Postoperative follow-up was completed with maximum duration of 122 months. RESULTS: Operative deaths (n=2) were due to acute circulatory failure related to hemodialysis. The most frequent cause of late deaths (n=10) was infection. Five (50%) patients died of sepsis, and 80% of sepsis was caused by leg infection associated with arteriosclerosis obliterans. There were 6 late cardiac events including 3 cardiac deaths. The actual survival rates 1, 3, 5 and 7 years after CABG were 68.6%, 42.5%, 35.4% and 35.4%, respectively. And the actual cardiac event free rates 1, 3, 5 and 7 years after CABG were 77.6%, 77.6%, 46.6% and 46.6%, respectively. Operative mortality (p=0.019), long-term survival (p<0.001) and cardiac event free rate (p=0.002) were significantly poorer in hemodialysis patients than in non-hemodialysis patients. However, the long-term survival rate of our hemodialysis patients receiving isolated CABG was almost similar to that in dialysis patients without CABG. The etiology of chronic renal failure did not significantly affect long-term RESULTS. Using internal thoracic artery graft significantly (p=0.02) decreased the late cardiac event in hemodialysis patients, although it did not improve late survival. CONCLUSIONS: Primary CABG followed by aggressive re-intervention have the benefit of preventing late cardiac death in hemodialysis patients. However, prevention of sepsis and treatment of arteriosclerosis obliterans are important for improving the late survival in hemodialysis patients receiving isolated CABG.

Role of STAT3 in ischemic preconditioning.

We recently demonstrated that ischemic preconditioning (IPC) induced by cyclic episodes of short durations of ischemia and reperfusion potentiates a signal transduction cascade involving protein tyrosine kinases and MAP kinases. A rapid activation of janus kinase (JAK) and several signal transducers and activators of the transcription (STATs) including STAT3, STAT5A and STAT6 has been shown to occur during myocardial ischemia and reperfusion. This study sought to examine if JAK/STAT signaling pathway play any role in classical early phase of IPC. Isolated working rat hearts were perfused for 15 min with KHB buffer in the absence or presence of a JAK kinase inhibitor tyrphostin AG490 (5 microm) followed by IPC, 30 min global ischemia and 2 h of reperfusion. The results demonstrated extensive phosphorylation of JAK2 and STAT3 in the IPC hearts which was almost completely abolished by an inhibitor of JAK2, AG490. IPC displayed cardioprotection as evidenced by improved post-ischemic contractile recovery, decreased myocardial infarct size and reduced number of apoptotic cardiomyocytes. AG490 blocked IPC-mediated cardioprotection by altering the IPC-mediated survival signal into death signal. Thus, IPC-induced upregulation of antiapoptotic gene bcl-2 and downregulation of pro-apoptotic gene bax are decreased and increased, respectively, in the AG490 treated hearts. The results suggest that early phase of IPC potentiates JAK/STAT signaling by activating STAT3 which transmits a survival signal to the myocardium.

An essential role of the antioxidant gene Bcl-2 in myocardial adaptation to ischemia: an insight with antisense Bcl-2 therapy.

Reperfusion of ischemic myocardium results in apoptotic cell death, which can be blocked by adapting the heart to ischemic stress induced by cyclic episodes of brief periods of ischemia and reperfusion. In concert, the antiapoptotic gene bcl-2 is decreased by ischemia/reperfusion, but increased in the ischemically adapted myocardium. To examine if bcl-2 plays a crucial role in cardioprotection, adaptive cardioprotection was further examined in the hearts treated with antisense bcl-2 oligodeoxynucleotides (ODN). Isolated Langendorff-perfused rat hearts were divided into three groups: control (perfused with Krebs-Henseleit bicarbonate buffer for 210 min); 30-min ischemia followed by 2-h reperfusion; ischemic adaptation followed by 30-min ischemia and 2-h reperfusion. The last (adapted heart) group was subdivided into another two groups: one was transfected 48 h earlier with antisense bcl-2 ODN, whereas the other group was transfected with sense bcl-2 ODN. Cardioprotection was examined by determining cardiomyocyte death due to necrosis and apoptosis. Antisense gene therapy almost completely abolished bcl-2 protein expression in the hearts. Bcl-2 mRNA was down-regulated in the ischemic/reperfused heart, but up-regulated in the adapted myocardium. Adapted myocardium showed decreased infarct size and reduced number of apoptotic cardiomyocytes. Ischemia/reperfusion resulted in increased oxidative stress as evidenced by increased malonaldehyde formation. Adapted myocardium had a reduced amount of malonaldehyde. Antisense bcl-2 ODN completely abolished the cardioprotective effects of adaptation by eliminating the antideath signal of bcl-2. In concert, reduced oxidative stress in the adapted myocardium no longer persisted. The results suggest an antioxidant role of bcl-2 that appeared to be essential for the cardioprotection achieved by ischemic adaptation.

Insulin-like growth factor 1 prevents neuronal cell death and paraplegia in the rabbit model of spinal cord ischemia.

OBJECTIVE: Insulin-like growth factor 1 has been shown to be cytoprotective against ischemia-reperfusion injury in various organs. However, spinal cord protection by insulin-like growth factor 1 has not been tested. We have therefore examined the effect of insulin-like growth factor 1 on neuronal cell death and motor function after spinal cord ischemia. METHODS: Japanese white rabbits were subjected to spinal cord ischemia by clamping the abdominal aorta for 15 minutes. Insulin-like growth factor 1 (0.3 mg/kg) at a dose equipotent to insulin (0.3 IU/kg) in lowering blood glucose level or the control (phosphate-buffered saline solution as a vehicle) was administered intravenously 30 minutes before the aortic clamp. RESULTS: Hind-limb motor function had recovered normally 48 hours after the operation in all the rabbits (n = 8) treated with insulin-like growth factor 1. In contrast, all the control-treated (n = 8) and all but one of the insulin-treated (n = 6) rabbits had deteriorated to paraplegia by 48 hours after the operation. Histopathologic sections in the involved spinal cord segment showed that a significantly (P <.0001) greater number of motor neuron cells were preserved in the rabbits treated with insulin-like growth factor 1 (17.9 +/- 4.8 per section) than in those treated with the control (8.0 +/- 2.1). Although insulin was equipotent to insulin-like growth factor 1 in preserving the number of motor neuron cells (18.5 +/- 2.7), the percentage of motor neuron cells positive for terminal deoxynucleotidyltransferase-mediated deoxyuridine triphosphate-biotin nick-end labeling were significantly (P <.01) smaller in the rabbits treated with insulin-like growth factor 1 (6.0 +/- 4.6) compared with those treated with the control (54.6 +/- 33.8) and insulin (26.2 +/- 11.7). Immunohistochemical studies revealed that insulin-like growth factor 1 increased expression of the antiapoptotic Bcl-xL protein and inhibited expression of the proapoptotic Bax protein in motor neuron cells 24 and 48 hours after the operation. In contrast, expression of only Bax was increased after the operation in other groups of rabbits subjected to spinal cord ischemia. CONCLUSIONS: These results suggest that insulin-like growth factor 1, but not insulin with a conventional dose, protects motor neuron cells from ischemic spinal cord injury associated with differential regulation of Bcl-xL and Bax protein.

Cerebral protection during surgery for aortic arch aneurysms.

Surgical repair of aneurysms or dissections involving the transverse aortic arch and the distal aortic arch carries a considerable risk of cerebral complications. Currently, deep hypothermic circulatory arrest (DHCA), moderate hypothermic circulatory arrest or DHCA with selective cerebral perfusion (SCP) and DHCA with retrograde cerebral perfusion (RCP) are used as means to protect the central nervous system. DHCA alone is simple, but the safe time of DHCA is limited. RCP is an alternative technique for cerebral protection that can prolong the safe time of DHCA. SCP offers virtually unlimited time in isolating cerebral circulation. With the improvement of cardiopulmonary bypass (CPB) materials and myocardial preservation, DHCA with SCP is our current preference of an adjunct for cerebral protection, although possible increment of mortality and morbidity associated with a prolonged DHCA and CPB remains to be overcome.

Dual involvement of coenzyme Q10 in redox signaling and inhibition of death signaling in the rat heart mitochondria.

Coenzyme Q10 (CoQ) has long been utilized as a cardioprotective agent in various heart diseases. One of the most important mechanisms by which CoQ exerts cardioprotection is aerobic ATP production as a mobile electron carrier in the mitochondrial electron transfer chain. The ability of CoQ to afford myocardial protection is also attributed to its antioxidant property. However, CoQ may also act as a pro-oxidant through the generation of reactive oxygen species. Although excess oxidative stress is known to induce death signaling via cytochrome c release from mitochondria, it is now apparent that a brief exposure to oxidative stress stimulates redox signaling for acquisition of tolerance to oxidative stress. Therefore, we have investigated dual involvement of CoQ in redox signaling generation through enhanced production of reactive oxygen species and death signaling inhibition through antioxidation. Mitochondria were isolated from the rat heart and incubated with CoQ (10 or 100 microM) or its vehicle HCO 60 for 1 h. H2O2 and cytochrome c release from respiring mitochondria were increased by antimycin A (2 microM), an inhibitor of complex III respiratory chain, or by high Ca2+ (10 microM). This enhanced release of H2O2 was associated with an increase in lipid peroxidation as measured with 4-hydroxy-2-nonenal-modified proteins and with large amplitude swelling of mitochondria. CoQ potentiated H2O2 release from antimycin A- or high Ca(2+)-treated mitochondria, but was capable of inhibiting lipid peroxidation and large amplitude swelling, and attenuated cytochrome c release from the mitochondria. In addition, CoQ increased ATP synthesis by mitochondria. These results suggest that CoQ plays dual roles in mitochondrial generation of intracellular signaling. CoQ acts as a pro-oxidant that participates in redox signaling. CoQ also acts as an antioxidant that inhibits permeability transition and cytochrome c release, and increases ATP synthesis, thereby attenuating death signaling toward apoptosis and necrosis.

Patch repair of postinfarction pseudo- and subepicardial aneurysm of the left ventricle.

Left ventricular pseudo-aneurysm and subepicardial aneurysm are rare complications of myocardial infarction. However, the prognosis of medical treatment is extremely poor and the operative procedure is controversial. We experienced 3 consecutive patients with this unusual left ventricular aneurysm, and described the clinical presentation, operative procedure and its result in these patients. The interval from myocardial infarction to discovering aneurysmal formation is short. The term was within a month. In all patients, the papillary muscle was in the proximity of the orifice of the aneurysm. Patch repair of these unusual left ventricular aneurysms may be effective for improvement of left ventricular function without mitral regurgitation.

Developmental changes in Cl(-)-ATPase activity in rat brains.

Developmental changes in brain Cl(-)-ATPase activity were examined using fetal, neonatal and adult rats. The Cl(-)-ATPase activity rapidly increased over 20 postnatal days to a level four-fold higher than that in an 18-day-old fetus. On Western blot analysis using an anti-Cl(-)-ATPase/pump 51 kDa subunit (ClP51) antibody, the amount of ClP51 protein increased in parallel with Cl(-)-ATPase activity. Immunohistochemistry using the same antibody showed Cl(-)-ATPase-like immunoreactivity on the cell membranes of neurons such as cerebral and hippocampal pyramidal cells and cerebellar Purkinje cells, where the immunoreactivity increased with developmental changes in the size and shape of the neurons. These findings suggest that neuronal Cl(-)-ATPase activity markedly increases during early postnatal development with an increase in the amount of Cl(-)-ATPase protein, which may support the formation of inwardly directed neuronal Cl(-) gradients.

Revascularization of left subclavian artery for coronary subclavian steal syndrome.

We have experienced 2 patients with coronary subclavian steal syndrome which progressed each to a different prognosis. Both cases received percutaneous transluminal angioplasty for subclavian artery stenosis after coronary artery bypass grafting. Although one case is doing well without any symptoms, the other case required axilloaxillary artery bypass grafting for the subclavian artery restenosis.

Role of granuloma in the immunopathogenesis of Crohn's disease.

Inflammatory bowel diseases (ulcerative colitis and Crohn's disease) are chronic long-lasting inflammatory diseases with yet unknown etiology. Recent advancement revealed that both diseases are associated with genetic predisposition and environmental factors such as luminal microorganisms and antigens. Crohn's disease is associated with histopathologic features such as granuloma formation and longitudinal ulceration. In this article we describe the role of granuloma in the immunopathogenesis of Crohn's disease. Granuloma of Crohn's disease may play crucial roles as antigen-presenting cites to memory type T cells, which leads to activation and proliferation of T cells. Antigens presented at granuloma may be closely related to the disease.

Bradycardia-induced long QT syndrome caused by a de novo missense mutation in the S2-S3 inner loop of HERG.

Long QT syndrome is a congenital disorder that presents with a defective cardiac ion channel and is either associated with prolonged action potential or, more commonly, known as an acquired form in which "torsades de pointes" type arrhythmias specifically occur after secondary causes. We report a case of a novel HERG mutation (A490T) that caused a bradycardia-associated form of long QT syndrome. A 27-year-old woman exhibited recurrent syncope due to torsades de pointes associated with a disturbance of the cardiac conduction system. By using polymerase chain reaction and single strand conformational polymorphism analyses, we identified a heterozygous single nucleotide substitution of HERG (G to A at nt 1468). This mutational change was not present in 140 Japanese control individuals. Electrophysiological assays for the A490T mutant HERG channel were conducted in the heterologous expression system with COS7 cells. The mutant channel was found to reconstitute functional channel currents, suggesting the homomeric mutant channel was functional. The mutation did not change the properties of the activation gate and inward rectification, however the current density of this mutant channel was small compared with that of wild type HERG. Taken together, this mutant may cause subtle changes in HERG channel functions (I(Kr)) in vivo. In this case, genetic background and unexpected bradycardia may have contributed to the development of long QT syndrome.

Hypoxia/reoxygenation promotes myocardial angiogenesis via an NF kappa B-dependent mechanism in a rat model of chronic myocardial infarction.

Therapeutic angiogenesis achieved either through the use of discreet angiogenic proteins or by gene therapy is fast emerging as a highly attractive treatment modality for ischemic heart disease. Herein we examine a novel method of stimulating myocardial angiogenesis by hypoxic preconditioning at both capillary and arteriolar levels, and the potential role of NF kappa B in mediating such a response. We also investigate the functional relevance of such treatment by assessing whether the induced neovascularization can help preserve left ventricular contractile functional reserve in the setting of developing heart failure secondary to myocardial infarction. Male Sprague-Dawley rats were randomly divided into eight groups: normoxia + sham surgery (NS), normoxia + permanent left anterior descending coronary artery (LAD) occlusion (NMI), hypoxic preconditioning + sham surgery (HS), hypoxic preconditioning + permanent LAD occlusion (HMI), PDTC (NF kappa B inhibitor) + hypoxic preconditioning + LAD occlusion (PHMI), PDTC+normoxia + LAD occlusion (PNMI), PDTC + hypoxic preconditioning + sham surgery (PHS) and PDTC + normoxia + sham surgery (PNS). Rats in the preconditioned groups were subjected to systemic hypoxemic hypoxic exposure (10+/-0.4% O2) for 4 h followed by a 24-h period of normoxic reoxygenation prior to undergoing LAD occlusion. Rats in the normoxia groups were time matched with the preconditioned group and maintained under normoxic conditions for the 28-h period prior to LAD occlusion. The HMI group displayed significant increases in capillary as well as arteriolar density after 2, 4 and 7 days post-operation compared to the NMI. Prior PDTC administration prevented such increases in the PHMI group and effectively abolished the pro-angiogenic effect of hypoxic preconditioning (HP). One week after sham surgery or LAD occlusion, rats underwent a pharmacological stress test with dobutamine in progressively increasing doses which revealed significantly elevated values of dp/dt(max) at each dose point in the HMI group compared to the NMI or PHMI groups. Hypoxic preconditioning also decreases endothelial cell injury as determined by the extent of endothelial cell apoptosis using anti-VWF factor labelling and TUNEL assay. The results suggest that HP stimulates myocardial angiogenesis via redox-regulated transcription factor, NF kappa B-dependent pathway to an extent sufficient to exert significant preservation of contractile functional reserve in a rat model of myocardial infarction progressing to heart failure.