Percutaneous transcatheter aortic valve replacement: first transapical implant in Asia.

Percutaneous transcatheter implantation of the aortic valve has been demonstrated as an alternative to open heart surgery in high-risk patients with symptomatic severe aortic stenosis (AS) who are not suitable for open surgery. The majority of these new devices are delivered via the transfemoral approach. However, due to the current size of delivery sheaths, the small and tortuous iliofemoral anatomy makes this approach challenging. The transapical approach provides a viable option for this patient subgroup. The first-in-Asia transcatheter aortic valve implantation via the transapical route is described. A 79-year-old Chinese woman with symptomatic severe AS and peripheral arterial disease, who was at high surgical risk, was successfully treated, and had good functional and haemodynamic results at the three-month follow-up.

The NRG1 gene is frequently silenced by methylation in breast cancers and is a strong candidate for the 8p tumour suppressor gene.

Neuregulin-1 (NRG1) is both a candidate oncogene and a candidate tumour suppressor gene. It not only encodes the heregulins and other mitogenic ligands for the ERBB family, but also causes apoptosis in NRG1-expressing cells. We found that most breast cancer cell lines had reduced or undetectable expression of NRG1. This included cell lines that had translocation breaks in the gene. Similarly, expression in cancers was generally comparable to or less than that in various normal breast samples. Many non-expressing cell lines had extensive methylation of the CpG island at the principal transcription start site at exon 2 of NRG1. Expression was reactivated by demethylation. Many tumours also showed methylation, whereas normal mammary epithelial fragments had none. Lower NRG1 expression correlated with higher methylation. Small interfering RNA (siRNA)-mediated depletion of NRG1 increased net proliferation in a normal breast cell line and a breast cancer cell line that expressed NRG1. The short arm of chromosome 8 is frequently lost in epithelial cancers, and NRG1 is the most centromeric gene that is always affected. NRG1 may therefore be the major tumour suppressor gene postulated to be on 8p: it is in the correct location, is antiproliferative and is silenced in many breast cancers.

Percutaneous transcatheter aortic valve replacement: first transfemoral implant in Asia.

Surgical aortic valve replacement (AVR) is the standard of care for patients with symptomatic severe aortic stenosis (AS), providing relief of symptoms and prolonging survival. However, many patients are either denied or not offered surgery due to high surgical risk or non-operability for open AVR. The technology of percutaneous aortic valve implantation emerged in 2002, and has since evolved rapidly with satisfactory results. Currently, almost all the procedures are performed predominantly in Europe and North America. The first-in-Asia percutaneous transcatheter aortic valve implantation via the transfemoral route is described. A 77-year-old man with symptomatic severe AS and at high surgical risk was successfully treated, with sustained clinical improvement and satisfactory haemodynamic results at 30-day follow-up.

Resection of a giant malignant mediastinal peripheral nerve sheath tumour under cardiopulmonary bypass.

Malignant peripheral nerve sheath tumour (MPNST) is a rare occurrence in the mediastinum. It is biologically aggressive and is generally resistant to chemoradiation therapy. The mainstay of treatment is complete surgical resection. We report a large MPNST which invaded into the adjacent aortic wall in a 50-year-old man. Extensive resection, which included aortic reconstruction under cardiopulmonary bypass and deep hypothermic arrest, was necessary for a good long-term outcome.

CT appearance of complications related to thoracic endovascular aortic repair (TEVAR): a pictorial essay.

Thoracic endovascular aortic repair (TEVAR) is a recognized treatment for various diseases involving the thoracic aorta. Patients treated with TEVAR require lifelong surveillance for potential complications, with CT being highly utilized in most centres. Endoleak is the most common complication and can be detected using CT. However, other complications such as stent strut perforations and end organ ischemia can also be detected on CT. The purpose of this pictorial essay is to illustrate the CT appearance of post-TEVAR complications encountered in our institution and to highlight their significance.

Bilateral pneumothoraces as a complication of acupuncture.

Pneumothorax developing secondary to acupuncture is rare. However, in an undiagnosed case, it may cause fatality. The real incidence of acupuncture-related pneumothorax is not known but is acknowledged to be underdiagnosed and under-reported. We describe pneumothorax occurring in a 52-year-old woman who developed bilateral pneumothoraces, with one side being a tension pneumothorax, immediately following acupuncture. The needle was inserted at a paravertebral point at the level of the third vertebral spinous process.

Differential upregulation of Nox homologues of NADPH oxidase by tumor necrosis factor-alpha in human aortic smooth muscle and embryonic kidney cells.

NADPH oxidases are important sources of vascular superoxide, which has been linked to the pathogenesis of atherosclerosis. Previously we demonstrated that the Nox4 subunit of NADPH oxidase is a critical catalytic component for superoxide production in quiescent vascular smooth muscle cells. In this study we sought to determine the role of Nox4 in superoxide production in human aortic smooth muscle cells (AoSMC) and embryonic kidney (HEK293) cells under proinflammatory conditions. Incubation with tumor necrosis factor-alpha (TNF-alpha, 10 ng/ml) for 12 h increased superoxide production in both cell types, whereas angiotensin II, platelet-derived growth factor or interleukin-1beta had little effects. Superoxide production was completely abolished by the NADPH oxidase inhibitors diphenyline iodonium and apocynin, but not by inhibitors of xanthine oxidase, nitric oxide synthase or mitochondrial electron transport. TNF-alpha upregulated the expression of Nox4 in AoSMC at both message and protein levels, while Nox1 and Nox2 were unchanged. In contrast, upregulation of Nox2 appeared to mediate the enhanced superoxide production by TNF-alpha in HEK293 cells. We suggest that Nox4 may be involved in increased superoxide generation in vascular smooth muscle cells under proinflammatory conditions.

Beyond Ortner's syndrome--unusual pulmonary complications of the giant left atrium.

INTRODUCTION: The giant left atrium (GLA) is a complication of severe mitral valve disease and causes morbidity by compressing adjacent intra-thoracic structures. CLINICAL PICTURE: We report 2 cases of unusual pulmonary complications of the GLA. Case 1 developed recurrent collapse of the left lung due to left main bronchus compression. Case 2 was diagnosed with right middle lobe compression and collapse. TREATMENT AND OUTCOME: Case 1 was successfully treated by mitral valve replacement and left atrial reduction surgery. Case 2 was treated conservatively. CONCLUSION: Pulmonary atelectasis may occur in patients with GLA due to bronchopulmonary compression. Surgical management with valve replacement and atrial reduction may be necessary to relieve airway compression.

Surgery for atrial fibrillation.

Atrial fibrillation is the most common sustained cardiac arrhythmia and is associated with significant morbidity and mortality. Surgical treatment is the most effective means of curing atrial fibrillation. The classic Cox maze procedure eliminates atrial fibrillation in more than 90% of patients and has remained the gold standard in surgery for atrial fibrillation. Despite being highly effective, the complexity of the procedure and long operating time associated with the operation has prevented its widespread application by surgeons. Advances in the understanding of the pathogenesis of atrial fibrillation and development of new ablation technologies have fuelled renewed interest in and development of surgical ablation procedures for atrial fibrillation. These new procedures are simpler and easily reproducible and cure atrial fibrillation in approximately 80% of patients. This article reviews the development of surgery for atrial fibrillation and our experience with the radiofrequency Cox maze III procedure.

Coronary artery bypass grafts in situs inversus.

Coronary artery bypass grafting in dextrocardia is rare. A case is described for the first time where both arterial and venous conduits were used. The subtle changes required in the conduct of the operation are highlighted.

Pericardiectomy in calcific constrictive pericarditis aided by Midas Rex drill.

Surgery for constrictive pericarditis has become a rare entity now. Various non-cardiac surgical measures are sometimes tried to remove the calcific plaques on the surface without damaging the underlying cardiac structures. We report a case of severe calcific pericarditis in which the Midas Rex neurosurgical drill was successfully used to facilitate pericardiectomy. Such a case has not been previously reported in the literature.

Effects of micromolar concentrations of manganese, copper, and zinc on alpha1-adrenoceptor-mediating contraction in rat aorta.

To determine the influences of the Mn, Cu, and Zn on alpha1-adrenoceptor (AR)-mediated vasoconstriction, we investigated their effects on vasoconstriction produced by the alpha1-AR agonist phenylephrine in isolated rings of rat thoracic aorta. The cumulative concentration-contraction curves for phenylephrine were obtained in the absence and presence of Mn (0.3, 1, 3 microM), Cu (1, 10, 16 microM), and Zn (0.3, 1, 10 microM). Mn, Cu, and Zn each inhibited phenylephrine-mediated contraction in a dose-dependent manner. The maximal phenylephrine-induced contraction was significantly reduced by the pretreatment of the arterial rings with 10 and 16 microM Cu (p<0.05). The results suggest that variations in the plasma concentrations of metal might lead to changes in alpha1-AR-mediated constrictive response.

DNA binding mediated by the wheat HMGa protein: a novel instance of selectivity against alternating GC sequence.

The high-mobility-group (HMG) chromosomal protein wheat HMGa was purified to homogeneity and tested for its binding characteristics to double-stranded DNA. Wheat HMGa was able to bind to P268, an A/T-rich fragment derived from the pea plastocyanin gene promoter, producing a small mobility shift in gel retardation assays where the bound complex was sensitive to addition of proteinase K but resistant to heat treatment of the protein, consistent with the identity of wheat HMGa as a putative HMG-I/Y protein. Gel retardation assays and southwestern hybridization analysis revealed that wheat HMGa could selectively interact with the DNA polynucleotides poly(dA).poly(dT), poly(dAdT).poly(dAdT), and poly(dG).poly(dC), but not with poly(dGdC).poly(dGdC). Surface plasmon resonance analysis determined the kinetic and affinity constants of sensor chip-immobilized wheat HMGa for double-stranded DNA 10-mers, revealing a good affinity of the protein for various dinucleotide combinations, except that of alternating GC sequence. Thus contrary to prior reports of a selectivity of wheat HMGa for A/T-rich DNA, the protein appears to be able to interact with sequences containing guanine and cytosine residues as well, except where G/C residues alternate directly in the primary sequence.

Targeted histone acetylation and altered nuclease accessibility over short regions of the pea plastocyanin gene.

The chromatin structure of the pea plastocyanin gene (PetE) was examined at three different transcriptional states by investigating the acetylation states of histones H3 and H4 and the nuclease accessibility of the gene in pea roots, etiolated shoots, and green shoots. The acetylation states of histones associated with different regions of PetE were analyzed by chromatin immunoprecipitation with antibodies specific for acetylated or nonacetylated histone H3 or H4 tails, followed by polymerase chain reaction quantification. Comparison of pea tissues indicated that histone hyperacetylation was associated with increased PetE transcription in green shoots. Moreover, hyperacetylation of both histones H3 and H4 was targeted to the enhancer/promoter region in green shoots, suggesting that only specific nucleosomes along the gene were modified. Time-course digestions of nuclei with micrococcal nuclease and DNaseI indicated that the enhancer/promoter region was more resistant to digestion in the inactive gene in pea roots than was the same region in the active gene in shoots, whereas the transcribed region of PetE was digested similarly among the tissues. This finding indicates that transcription is accompanied by changes in the nuclease accessibility of the enhancer/promoter region only. Moreover, these results indicate that the changes in nuclease accessibility are organ specific, whereas histone hyperacetylation is light dependent, and they suggest that changes in nuclease accessibility precede histone hyperacetylation during PetE activation.

Giant coronary aneurysms with multiple vascular aneurysms: a rare manifestation of hyperhomocysteinemia.

Hyperhomocysteinemia is associated with accelerated atherosclerosis, which leads to an increased incidence of premature vascular disease. Although multiple vascular aneurysms have been linked to hyperhomocysteinemia, coronary artery aneurysms have not. We report a case of giant coronary artery aneurysm associated with multiple peripheral vascular aneurysms in a patient with hyperhomocysteinemia.

Exogenous hyaluronidase induces release of nitric oxide from the coronary endothelium.

OBJECTIVE: Hyaluronidase, an endogenous enzyme that hydrolyzes mucopolysaccharides, has been shown to enhance myocardial protection when added to preservation solutions. In addition, hyaluronidase infusion reduces injury to ischemic myocardium. Endothelium-derived nitric oxide is an endogenous vasodilator that prevents leukocyte adhesion to the intima and inhibits platelet adhesion and aggregation in the coronary artery. Experiments were undertaken to determine whether the protective action of hyaluronidase could be mediated by the endogenous release of nitric oxide. METHODS: Segments of coronary artery, with and without endothelium, were placed in organ chambers (25 mL) to measure isometric force. Blood vessel segments were contracted with prostaglandin F(2)(alpha) (2 x 10(-6) mol/L) and exposed to hyaluronidase (3-15 units). RESULTS: Hyaluronidase induced vasodilation of arteries with intact endothelium but not of arteries without endothelium (n = 6, P<.05). Endothelium-dependent vasodilation to hyaluronidase was blocked by N(G)-monomethyl-L -arginine (10(-5) mol/L), an inhibitor of nitric oxide synthesis from L -arginine (n = 6, P<.05). Inhibition of vasodilation by N(G)-monomethyl-L -arginine was reversed by L -arginine (10(-4) mol/L) but not D -arginine (10(-4) mol/L; n = 6, each group). Vasodilation to hyaluronidase also was inhibited by hemoglobin (2 x 10(-6) mol/L), a scavenger of the nitric oxide radical (n = 6, P<.05). CONCLUSIONS: Hyaluronidase induces the release of nitric oxide from the coronary endothelium. Because nitric oxide, an endogenous vasodilator, inhibits leukocyte adhesion to the intima in addition to inhibiting platelet adhesion and aggregation, stimulated production of endothelium-derived nitric oxide by exogenous hyaluronidase could be the mechanism of the protective action of hyaluronidase infusion.

Successful repair of traumatic aortic tears using left heart bypass.

Aortic tears commonly occur in multiply injured patients. Recognizing this injury is important. A chest X-ray is helpful and a CT-angiogram or aortogram confirmatory. After attending to life-threatening injuries, the aortic tear should be repaired immediately. Using the left heart bypass technique has the lowest risk of operative neurologic injury. We review our experience over the last 2 years, discuss our preferred technique and report on the outcome.

Minimally invasive repair of atrial septal defects--a case series.

INTRODUCTION: Repair of atrial septal defects in adults has become so safe that emphasis is now placed on improving cosmesis without compromising safety. The results of our series of minimally invasive repair of atrial septal defects done through a lower partial sternotomy are reported. MATERIALS AND METHODS: Eight adult patients underwent minimally invasive repairs of atrial septal defects over a period of 1 year (Group 1). Conventional repairs of atrial septal defects were performed in 26 patients over the same period (Group 2). We describe the technique and compare our results on time taken for surgery, bypass time, cross clamp time, time to extubation and total hospital stay. Early complications and complications at 1 year are also presented. RESULTS: No difference in the demographic data was found between the two groups. The time taken for surgery was more, while cross clamp times and bypass times were shorter in Group 1. There was also no difference in the amount of blood loss, early postoperative complications and later complications like cardiac rhythm or wound pain. CONCLUSION: The improved cosmetic appearance, both in males and females, is an important factor to recommend minimally invasive repair of atrial septal defects in an adult population. Surgical closure of atrial septal defects can be performed through a lower partial sternotomy without compromising access or safety with good cosmetic outcome.