Dynamics of ultra-thin polystyrene with and without a (artificial) dead layer studied by resonance enhanced dynamic light scattering.

Using non-invasive, marker-free resonance enhanced dynamic light scattering, the dynamics of capillary waves on ultrathin polystyrene films' coupling to the viscoelastic and mechanical properties have been studied. The dynamics of ultrathin polymer films is still debated. In particular the question of what influence either the solid substrate and/or the fluid-gas interface has on the dynamics and the mechanical properties of films of glass forming liquids as polymers is in the focus of the present research. As a consequence, e.g., viscosity close to interfaces and thus the average viscosity of very thin films are prone to change. This study is focused on atactic, non-entangled polystyrene thin films on the gold surface. A slow dynamic mode was observed with Vogel-Fulcher-Tammann temperature dependence, slowing down with decreasing film thickness. We tentatively attribute this relaxation mode to overdamped capillary waves because of its temperature dependence and the dispersion with a wave vector which was found. No signs of a more mobile layer at the air/polymer interface or of a "dead layer" at the solid/polymer interface were found. Therefore we investigated the influence of an artificially created dead layer on the capillary wave dynamics by introducing covalently bound polystyrene polymer brushes as anchors. The dynamics was slowed down to a degree more than expected from theoretical work on the increase of density close to the solid liquid interface-instead of a "dead layer" of 2 nm, the interaction seems to extend more than 10 nm into the polymer.

Measuring the solubility of solids in non-solvents: case of polystyrene in alkanes.

We introduce a simple and sensitive technique for measuring extremely low solubilities with a small sample size and small solvent volume. This technique involves measuring the decrease in the thickness of a supported thin film after exposure to a drop of known volume of solvent and removal of the solution. The feasibility of measuring very small changes in film thickness directly translates to the ability to measure extremely low solubility while at the same time using only µL of solvent. We apply the technique to the case of polystyrene with Mw values in the range 2500 g/mol to 22200 g/mol in alkane solvents and show that we can easily measure a solubility of 0.1 g/L using only 1[Formula: see text] g of material and 3[Formula: see text] L of solvent for each sample.

First Report of Zonate Leaf Spot of Cinnamomum kanehirae Caused by Hinomyces moricola in Taiwan.

Cinnamomum kanehirae, a native tree of Taiwan, is an important tree that hosts popular medicinal fungi. In the winter of 2011, zonate leaf spots were observed at a nursery garden in Wu-Lai, Taiwan. Initial symptoms included small brown lesions on leaves that became larger leaf spots after expanding or fusing together, causing a leaf blight and eventually defoliation. Sporophores on the host were generally hypophyllous but sometimes amphigenous, solitary, erect, easily detachable. The upper portion of the sporophore was considered an individual conidium and consisted of a pyramidal head that was fusiform to ventricose, 320 to 580 µm long and 100 to 130 µm wide at the broadest point. Branches within the pyramidal head were short and compact, and dichotomously or trichotomously branched. The sporophore initials were hyaline, broad, septate, tapering toward an acute apex, and sometimes constricted at the basal septum. Sclerotia were observed in older lesions, grey or black, spherical, and 1 to 2.5 mm in diameter. The fungus was isolated from infected tissue and sporophores, maintained on potato dextrose agar (PDA) at 20°C in darkness. Sclerotia were produced on PDA after 4 to 5 weeks and were irregular or spherical, but sporophores didn't develop on agar medium. The fungus was identified as Hinomyces moricola on the basis of morphological characteristics (1). Koch's postulates were performed by inoculating four 1-year-old, asymptomatic, potted C. kanehirae plants; every plant was inoculated with sporophores from infected leaves on each of five leaves. Four noninoculated plants were kept in separate pots and served as controls. All plants were covered with transparent plastic bags individually and incubated in a growth chamber at 18 to 20°C. Symptoms were observed after 2 to 4 days on every inoculated plant but not on uninoculated plants. The leaf spots were similar to those originally observed. The pathogen was reisolated from spots of inoculated plants. The pathogenicity test was repeated once. H. moricola is known to cause severe defoliation on woody and annual plants, including at least 73 host species and 36 families distributed in the eastern United States and Japan (2). References: (1) N.-S. Tomoko et al. Mycoscience. 47:351, 2006. (2) J. C. Trolinger et al. Plant Dis. Reptr. 62:710, 1978.

First Report of Southern Blight of Mexican Petunia (Ruellia brittoniana) Caused by Sclerotium rolfsii in Taiwan.

Mexican petunia (Ruellia brittoniana) is an herbaceous flowering perennial with strikingly colored flowers, widely cultivated commercially as a potted plant and a popular garden plant. In July of 2010, root and stem rot that caused death was observed on Mexican petunia at the flower nursery of the Council of Agriculture & Chiayi County in Taiwan. Plants had rotted and girdled stem bases. Necrotic areas were covered with fans of white mycelium as well as abundant spherical sclerotia. A fungus was isolated from infected tissue and sclerotia, and maintained on potato dextrose agar (PDA) plates incubated at 25°C without light. Colonies were white, cottony, often forming fans; pure cultures were prepared by transferring hyphal tips to PDA. Sclerotia formed after 10 days, initially white becoming dark brown with age, and 0.5 to 0.6 mm in diameter. To confirm identity of the causal fungus, the complete internal transcribed spacer (ITS) rDNA region of the causal fungus was amplified using the primers ITS4 and ITS5 (2) and sequenced. The resulting sequence of 687 bp was uploaded in NCBI. The sequence was 98% similar to sequences of Athelia rolfsii (Sclerotium rolfsii) in NCBI (Accession No. JN543691.1). Koch's postulates were performed using two inoculation techniques. The soil near the base of healthy Mexican petunia plants (four plants per pot) were exposed to recently matured sclerotia (10 sclerotia per plant) developed from pure fungal cultures or 10-mm-diameter agar plugs of mycelium (one plug per plant). Noninoculated plants, in a separate pot, were used as a control. All plants were incubated in a growth chamber at 28 to 33°C. Disease symptoms occurred on all inoculated plants by 5 to 7 days and included yellowing of leaves, basal stem rot, and wilt. Ten days after inoculation, inoculated plants were dead whereas control plants remained healthy. The pathogenicity test was repeated twice with similar results and S. rolfsii was reisolated from infected plants in each test. The pathogen has been reported to cause substantial loss of Mexican petunia in Louisiana (1). The disease is becoming more common in Taiwan and could cause losses in Mexican petunia production. To our knowledge, this is the first report of disease on Mexican petunia caused by S. rolfsii in Taiwan. References: (1) G. E. Holcomb. Plant Dis. 88:770, 2004. (2) T. J. White et al. Page 315 in: PCR Protocols: A Guide to Methods and Applications. M. A. Innis et al., eds. Academic Press, 1990.

First Report of Southern Blight of Iresine herbstii Caused by Sclerotium rolfsii in Taiwan.

Widely cultivated commercially, Iresine herbstii Hook is a potted herbaceous plant popular for its foliage, which varies from a dark red to brownish maroon. In the summer of 2010, a sudden wilt of I. herbstii plants was observed at a recreational farm in Taipei City in northern Taiwan. The initial symptoms were water-soaked lesions that became soft and then rotted. Necrotic areas on the stems were covered with fans of white mycelium as well as abundant spherical, brown sclerotia. A fungus was isolated from both infected tissue and sclerotia and maintained on potato dextrose agar (PDA) plates incubated at 25°C without light. Colonies were white and cottony, often forming mycelial fans. Pure cultures were prepared by transferring single hyphal tips to PDA. Sclerotia formed after 7 days. Sclerotia were initially white becoming dark brown with age and were 0.8 to 1 mm in diameter at maturity. These are typical features of Sclerotium rolfsii. Koch's postulates were performed by inoculating five healthy, potted I. herbstii plants with 10 fresh sclerotia placed on the soil surface around the base of each plant. In a second test, five healthy potted plants were inoculated with a single 10-mm-diameter mycelial agar plug placed at the stem base of each plant. Five noninoculated plants served as controls. All plants were incubated in a growth chamber at 25 to 35°C. Basal stem rot and wilt developed within 4 days on plants inoculated with sclerotia or mycelial plugs. All plants were dead by 7 days after inoculation whereas the controls remained healthy. The fungus was reisolated from the symptomatic tissue and produced sclerotia and mycelium consistent with S. rolfsii. To confirm identity of the causal fungus, the complete internal transcribed spacer (ITS) rDNA region of the causal fungus was amplified using the primers ITS4 and ITS5 (3) and sequenced. The resulting sequence of 687 bp was uploaded in NCBI (Accession No. JN543691.1). The sequence was 98% similar to sequences of Athelia rolfsii (anamoprh S. rolfsii). This disease has been observed on many species of plants (1, 2). To our knowledge, this is the first report of I. herbstii caused by S. rolfsii in Taiwan or any other part of the world. References: (1) T. T. Chang. Bull. Taiwan For. Res. Inst. 9:191, 1994. (2) Y. N. Wang et al. J. Exp. For. Nat. Taiwan Univ. 20:45, 2006. (3) T. J. White et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, 1990.

Treatment of vitamin D deficiency in CKD patients with ergocalciferol: are current K/DOQI treatment guidelines adequate?

BACKGROUND: Vitamin D deficiency/insufficiency (VDDI) is common in CKD patients and may be associated with abnormal mineral metabolism. It is not clear whether the K/DOQI recommended doses of ergocalciferol are adequate for correction of VDDI and hyperparathyroidism. METHODS: Retrospective study of 88 patients with CKD Stages 1 - 5 and baseline 25-hydroxyvitamin D level < 30 ng/ml (< 75 nmol/l). Patients treated with ergocalciferol as recommended by K/DOQI guidelines. Only 53 patients had elevated baseline PTH level for the CKD stage. Patients were excluded if they received vitamin D preparations other than ergocalciferol or phosphate binders. 25-hydroxyvitamin D level, intact PTH level (iPTH), and other parameters of mineral metabolism were measured at baseline and after completion of ergocalciferol course. RESULTS: 88 patients with CKD were treated with ergocalciferol. Mean age 56.8 +/- 9.5 years and 41% were males. The mean (+/- SD) GFR was 28.3 +/- 16.6 ml/min. At the end of the 6-month period of ergocalciferol treatment, the mean 25-hydroxyvitamin D level increased from 15.1 +/- 5.8 to 23.3 +/- 11.8 ng/ml (37.75 +/- 14.5 to 58.25 +/- 29.5 nmol/l) (p < 0.001). Treatment led to > or = 5 ng/ml (12.5 nmol/l) increases in 25-hydroxyvitamin D level in 54% of treated patients, and only 25% achieved levels > or = 30 ng/ml (75 nmol/l). Mean iPTH level decreased from 157.9 +/- 125.9 to 150.7 +/- 127.5 pg/ml (p = 0.5). Only 26% of patients had > or = 30% decrease in their iPTH level after treatment with ergocalciferol. CONCLUSIONS: Current K/DOQI guidelines are inadequate for correcting VDDI or secondary hyperparathyroidism in CKD patients. Future studies should examine the effects of higher or more frequent dosing of ergocalciferol on these clinical endpoints.

Neuroimaging Appearance of Cerebral Malignant Epithelioid Glioneuronal Tumors in Children.

Malignant epithelioid glioneuronal tumor is a rare high-grade, aggressive brain tumor that shows both glial and neuronal differentiation on histopathology but is not included in the current World Health Organization classification. The neuroimaging appearance is variable but may be secondary to the size of the mass and/or location of the tumor. In our series, all epithelioid glioneuronal tumors were encountered in the supratentorial space and included pineal, temporal, and extratemporal lobar cerebral hemisphere locations. When large, the tumors demonstrate cystic degeneration and necrosis, hemorrhage, contrast enhancement, and regions of low apparent diffusion coefficient scalars consistent with patterns seen with other high-grade pediatric brain tumors. The tumors also have a propensity to spread into the meninges at presentation and for distant CSF spread on follow-up imaging.

Moderating effects of coping styles on anxiety and depressive symptoms caused by psychological stress in Chinese patients with Type 2 diabetes.

AIMS: This study aimed to assess possible interactive effects of coping styles and psychological stress on depression and anxiety symptoms in Chinese patients with Type 2 diabetes. METHODS: Three hundred and four patients with Type 2 diabetes underwent a face-to-face interview by trained research staff according to a standardized questionnaire including information on socio-demographic characteristics, psychological stress, coping styles and anxiety and depressive symptoms. The interactive effects of coping styles and psychological stress on depression and anxiety symptoms were assessed by hierarchical multiple regression analyses. RESULTS: There were significant associations of the four domains of psychological stress with anxiety and depressive symptoms, except for the relationship between 'reduced economic condition' and depressive symptoms. 'Negative coping style' significantly increased the level of both anxiety and depressive symptoms; whereas, 'active coping style' and 'avoidant coping style' decreased the risk of depressive symptoms. The interactions of 'negative coping style' with 'worrying about decline in body/physical function' and 'reduced economic condition' significantly increased the risk of anxiety and depressive symptoms, and the interaction of 'social/family crisis caused by the disease' with 'avoidance coping style' and 'worrying about decline in body/physical function' with 'active coping style' significantly decreased the risk of depressive symptoms. CONCLUSIONS: The results of this study suggest that certain coping styles might moderate the association of psychological stress with anxiety and depressive symptoms in Chinese patients with Type 2 diabetes.

The significance of endograft geometry on the incidence of intraprosthetic thrombus deposits after abdominal endovascular grafting.

OBJECTIVES: To examine the incidence and risk factors of intraprosthetic thrombotic deposits in abdominal aortic endografts. METHODS: The clinical records of 51 patients (44 males; mean age 76.3 years, range: 63-90 years) with abdominal aortic aneurysm treated with transfemoral implantation of bifurcated stent graft between the years 2002 and 2008 were retrospectively reviewed. Patients underwent three-phase helical computed tomographic (CT) examinations at 1-, 3-, 6- and 12-month intervals and then annually. The formation of intraprosthetic thrombus associated with use of anti-platelet, preoperative mural thrombus in the aneurysm, ratio of cross-sectional area between the mainbody and bilateral limb grafts and length of mainbody were evaluated. RESULTS: Over a 10-month mean follow-up, intraluminal deposits of thrombotic material were observed in eight of 51 patients (15.6%, 95% confidence interval: 8.2-28). The first signs of thrombus formation occurred on average 9.8 months after endografting (range: 1-24 months). Intraprosthetic thrombotic deposits was not related to preoperative mural thrombus formation (p=0.38) or postoperative anti-platelet or anticoagulation medication (p=0.40). However, it was significantly related to the ratio of the cross-sectional area between the mainbody and the bilateral limb grafts and the length of mainbody (p=0.04 and p=0.01). There were three graft limbs occlusion owing to kinking with no intraprosthetic thrombus detected on CT scans taken prior to occlusion. One patient developed distal left proximal superior femoral artery embolisation 4 months after detectable intraprosthetic mainbody thrombus in a CT scan follow-up. In no case did the thrombotic deposits clear completely from the prosthesis lumen during follow-up. CONCLUSIONS: This short experience demonstrates that incidentally found thrombotic deposits in abdominal aortic endografts are common. The deposition of thrombus is mostly influenced by the geometry of the aortic stent graft with wider mainbody diameter coupled with smaller limb grafts and longer mainbody graft. Most of these thrombi are clinically silent and require no additional treatment.

Porphyrin with amino acid moieties: a tumor photosensitizer.

A porphyrin with amino acid moieties was synthesized in this work, which may be a latent photosensitizer for photodynamic therapy (PDT). Adler's strategy was used to synthesize meso-tetra (4-nitrophenyl) porphyrin (TNPP) through cyclolization of 4-nitrobenzaldhyde and pyrrole in refluxed nitrobenzene. Reduction of TNPP yielded meso-tetra(4-aminophenyl) porphyrin (TAPP). The synthesis was improved by employing lactic acid as a catalyst. Based on TAPP, porphyrin with valine (TAPP-4Val) was obtained. The application of the resultant TAPP-4Val as tumor photosensitizer on human breast tumor cells for photodynamic therapy (PDT) was preliminarily explored. Dark-toxicity evaluations showed that, under a concentration at up to 6 x 10(-6) M, the survival of MCF-7 cells was larger than 90%, which means TAPP-4Val is almost of non-cytotoxicity. However, TAPP-4Val showed remarkable phototoxicity after visible light irradiation. Effects of irradiation time on the survival of cells under typical concentrations of TAPP-4Val were also studied. The new porphyrin with amino acid moieties, TAPP-4Val, is of high phototoxicity but minimal or no dark-toxicity, which can be used as an effective photosensitizer for PDT.

Extracorporeal membrane oxygenation hybrid with various ventricular assist devices as double bridge to heart transplantation.

Ventricular assist devices (VAD) have benefitted patients with end-stage heart failure as a bridge to heart transplantation (HTx). We present our experience with HTx after an extracorporeal membrane oxygenation (ECMO) hybrid with various ventricular assist devices (VAD). From May 1996 to December 2003, mechanical circulatory support with a Biopump VAD was performed in eight patients, HeartMate left VAD in eight patients, and Thoratec VAD in eight patients. Before VAD implantation, 19 patients maintained their circulation with ECMO. Half of the 24 patients were implanted with VAD to await a suitable donor for HTx. We observed that half of the patients supported by ECMO hybrid with various VAD awaited a suitable donor for HTx. In our experience, we recommend the application of ECMO for short-term support within 1 week and the Biopump VAD, Thoractec VAD, or HeartMate VAD for medium-term or long-term support as a bridge to HTx.

Sparing immunosuppression in heart transplant recipients with severe sepsis.

This study described an analysis of severe sepsis among heart transplantation recipients who were treated by sparing all immunosuppressants. Sepsis leading to multiple organ failure (MOF) in heart transplantation has a high mortality. This retrospective study of 190 patients who underwent heart transplantation from 1993 to 2004 included 12 who had severe sepsis with MOF who were treated by sparing all immunosuppressants. Half of them survived after sparing all immunosuppressants with intensive endomyocardial biopsy. Only one case needed pulse therapy for an acute rejection episode. The most common bacterial infectious episodes were caused by methicillin-resistant Staphylococcus aureus (n = 3). All sepsis episodes occurred in the first month after heart transplantation except in one case, which occurred 6 years after heart transplantation. There was a 50% survival rate of heart transplantation recipients who experienced MOF due to severe sepsis and were treated by sparing all immunosuppressants under a program of intensive endomyocardial biopsy.

Heart retransplantation for heart allograft failure in Chinese heart transplant recipients: NTUH experience.

We investigated the short- and long-term results after heart retransplantation in terms of different causes of heart allograft failure. We sought to establish the data of heart retransplantation in Chinese compared with Western counterparts due to differences in heart allograft vasculopathy. From March 1995 to May 2005, eight heart transplantation recipients with allograft failure underwent retransplantation. Heart allograft failure was due to coronary vasculopathy (CAV) in six patients (75%) and acute rejection in two patients (25%). The mean interval to retransplantation was 32 to 84 months (mean 54.3 months). There were five patients who survived after heart retransplantation for CAV and no patient survived after an earlier diagnosis of acute rejection. Heart retransplantation is a feasible method with acceptable long-term survival rate for heart allograft failure. After careful pretransplant evaluation, retransplantation is acceptable. The survival after retransplantation for CAV is notably great than that after acute rejection. Heart retransplantation is the only way for patients who have cardiac allograft failure to achieve long-term survival.

Single-center experience of pediatric heart transplantation in taiwan.

Heart transplantation (HTx) is a treatment for end-stage heart failure or a complex or inoperable congenital defect. The long-term survival and the adequate donor to recipient body weight (D/R BW) ratio remain to be determined. From March 1995 to May 2004, 14 children (6 months-16 years of age) underwent HTx due to underlying diseases of idiopathic dilated cardiomyopathy (n = 10; 71.4%), congenital heart disease (n = 3; 21.4%), and Kawasaki disease (n = 1; 7.1%). Donor-recipient body weight ratio ranged from 0.89 to 3.9. Big heart syndrome was present in one patient when D/R BW ratio was more than 3. Actuarial survival was 92.9% at 5 years after transplantation. Only the one patient who had Kawasaki disease died due to early primary graft failure. HTx is a feasible method with good long-term survival rates for end-stage heart failure or for complex or inoperable congenital defects. After careful pretransplant evaluation, a high D/R BW ratio (more than 3) is acceptable.

[Infantile systemic hyalinosis: a case report and literature review].

Objective: To investigate the clinical, pathological and gene mutation features of infantile systemic hyalinosis(ISH). Method: Data of a child with ISH seen in Haikou Hospital were retrospectively analyzed for the diagnosis and differential diagnosis of infantile systemic hyalinosis and the relevant reports in literature were reviewed. Result: A 1 year and 1 month old boy showed limbs joint stiffness, limited mobility and double knee flexion at his first month of life. At third month, red rashes appeared on the body and gradually became purple, most of them were seen on the back and they were higher than the skin surface, uneven and did not fade when pressed. Undergoing X-ray the boy showed double knee varus deformity. Histopathological examination of the neck skin lesions proved hyalinosis. The gene examination revealed ANTXR2 exon 13, c. 1073 delC/c.1074 delT mutations, which were hot spots mutation of ISH, then the diagnosis of ISH was confirmed. Using "Infantile systemic hyalinosis" as a keyword, literature in Wanfang network, PubMed and China National Knowledge Infrastructure from 1978 to 2015 was searched, we found 48 foreign cases, one Chinese Taiwan case. All the cases had joint contractures. Short stature and skin lesions with hyperpigmentation in 40 cases, gingival hyperplasia in 36 cases, perianal nodules in 32 cases, skin thickening in 31 cases, osteoporosis in 30 cases, recurrent diarrhea in 30 cases, repeated infections in 25 cases; 49 cases were reported as autosomal recessive genetic disease, of whom 18 cases underwent genetic testing, the pathogenic gene was located in the fourth chromosome q21 position, the gene was encoded as capillary morphogenesis Protein 2 (CMG2), also known as anthrax toxin receptor 2 (ANTXR2), but there were various mutation spots in the gene. Among the 18 cases, 9 were of frameshift, 8 of missense and 1 of splice defect . Onset ages were mainly within 4 months after birth. Without special treatment most patients died at about 2 years of age due to repeated infections. Conclusion: ISH is a rare disease, which occurs at early age. ISH has special clinical features: joint contracture and limited mobility, special skin rash and pigmentation, skin hyaline degeneration of pathological examination. ISH is an autosomal recessive genetic disease with mutation gene located in the fourth chromosome q21 position. Currently there is no effective treatment for ISH, with which patients are prone to die of recurrent infections.

Vascular endothelial growth factor 189 mRNA isoform expression specifically correlates with tumor angiogenesis, patient survival, and postoperative relapse in non-small-cell lung cancer.

PURPOSE: The purpose of this study was to evaluate the correlation between the expression of four different vascular endothelial growth factor (VEGF) mRNA isoforms (VEGF121, VEGF165, VEGF 189, and VEGF206) and the clinicopathologic characteristics, tumor angiogenesis, and outcome of patients with non-small-cell lung cancer. PATIENTS AND METHODS: We examined the expression of four different VEGF mRNA isoforms in 57 non-small-cell lung cancers using reverse transcriptase polymerase chain reaction and the tumor angiogenesis using immunohistochemical staining. RESULTS: All 57 lung cancer samples expressed the VEGF121, VEGF165, and VEGF189 mRNA isoforms, and three expressed the VEGF206 mRNA isoform. A high tumoral VEGF189 mRNA isoform expression ratio was associated with a high intratumoral microvessel count (P = .013), short survival (< 24 months; P = .001), and early postoperative relapse (< 12 months; P = .001). Survival and postoperative relapse time were significantly shorter in patients with a high compared with a low tumor VEGF189 mRNA isoform expression ratio (P = .0001 and P = .0086, respectively, log-rank test). In contrast, the VEGF165 and VEGF 206 mRNA isoform expression ratios showed no statistical correlation with tumor angiogenesis, postoperative relapse time, or survival. A high VEGF121 mRNA isoform expression ratio was associated with short survival (< 24 months) and early relapse (< 12 months). Multivariate analysis showed that VEGF 189 mRNA isoform expression, microvessel count, and nodal status were the most important independent prognostic factors for patient survival and postoperation recurrence. CONCLUSION: The VEGF189 mRNA isoform expression ratio shows a greater correlation with tumor angiogenesis, postoperative relapse time, and survival than do the expression ratios for the VEGF121, VEGF165, and VEGF206 mRNA isoforms and can be used as a prognostic indicator for patients with non-small-cell lung cancers.

Experimentally created atrioventricular node reentrant tachycardia in the dog: evidence of a brake system for nodal reentry in the anterior interatrial septum.

OBJECTIVES: The purpose of the study was to investigate the hypothesis that nodal approaches of both anterior and posterior atrial input sites of the atrioventricular (AV) node contribute to part of the circuit of AV node reentrant tachycardia. Thus, tachycardia might be elicited by a premature atrial impulse that arrived at the AV node through one input site while blocked at another. BACKGROUND: Atrioventricular node reentrant tachycardia is the most common supraventricular tachycardia in humans, yet the exact pathway of the reentrant circuit is unknown. METHODS: In eight dogs, an operation that blocked atrial impulses from the anterior input site to the AV node was performed through a right thoracotomy with the inflow occlusion method. The right atrial free wall and the anterior atrial septum between the sinoatrial node and the AV node were completely divided, whereas the tissues within the triangle of Koch remained intact. Thus, atrial impulses were blocked from the anterior input site in the right atrium and the atrial septum and were conducted only through the left atrial free wall to the posterior atrial septum into the AV node. RESULTS: In a baseline electrophysiologic study before operation, dual AV conduction pathways were demonstrated in seven of eight dogs, but none of the seven had inducible AV node reentrant tachycardia. A repeat study 1 week postoperatively revealed that 1) both PR and AH intervals were prolonged during sinus rhythm (p < 0.01); 2) anterograde and retrograde conduction of the AV node showed no significant changes; and 3) AV node reentrant tachycardia was induced in four dogs (50%), of which three had sustained tachycardia. CONCLUSIONS: These results are compatible with the hypothesis that both nodal approaches of atrial input sites of the AV node contribute to part of the circuit of AV node reentrant tachycardia. They also confirm Moe's hypothesis of the existence of a brake system that prevents sustained AV node reentry. Our data suggest that the brake system is located in the anterior atrial septum.

Recovery of atrial function after atrial compartment operation for chronic atrial fibrillation in mitral valve disease.

OBJECTIVES: We prospectively studied the recovery of atrial function after atrial compartment operation and mitral valve surgery in patients with chronic atrial fibrillation caused by mitral valve disease. BACKGROUND: Chronic atrial fibrillation is the most common arrhythmia in mitral valve disease. This arrhythmia is associated with excessive morbidity and mortality. Mitral valve surgery alone rarely eliminates it. METHODS: Twenty-two patients underwent mitral valve surgery and a new surgical method, atrial compartment operation. Doppler echocardiography was performed in all patients before operation and at 1 week and 2 and 6 months after operation in the successful cardioversion group. Peak early diastolic (E) and atrial (A) filling velocities, peak A/E velocity ratio and A/E integral ratio of the mitral and tricuspid valves were measured. RESULTS: Sinus rhythm was restored immediately after operation in 91% of patients and was maintained for > 1 week in 15 (68%) of 22 patients and > 6 months in 14 (64%) of 22. Eleven of 15 patients had left atrial paralysis (A/E integral ratio 0) at 1 week and 6 of 14 patients at 2 months. Nine of 15 patients had right atrial paralysis (A/E integral ratio 0) at 1 week and 1 of 14 patients at 2 months. Both left and right atrial contractile function (presence of an A wave on Doppler findings) was detected at 6 months in 14 patients. Mean (+/- SD) peak atrial filling velocity of the mitral valve was 15 +/- 26 cm/s at 1 week, 38 +/- 39 cm/s at 2 months and 93 +/- 32 cm/s at 6 months (p < 0.001). Mean peak atrial filling velocity of the tricuspid valve was 14 +/- 19 cm/s at 1 week, 33 +/- 19 cm/s at 2 months and 50 +/- 19 cm/s at 6 months (p < 0.001). Peak early diastolic and atrial filling velocities, peak A/E velocity ratio and A/E integral ratio of the mitral and tricuspid valves increased significantly from 1 week to 6 months. CONCLUSIONS: Chronic atrial fibrillation in mitral valve disease can often be eliminated by atrial compartment operation. No surgical mortality or significant complications were encountered. Both left and right atrial function, as manifested by Doppler findings, recover after compartment operation and improve over time. The mechanical function of the right atrium recovers earlier than that of the left.

Down-regulation of L-type calcium channel and sarcoplasmic reticular Ca(2+)-ATPase mRNA in human atrial fibrillation without significant change in the mRNA of ryanodine receptor, calsequestrin and phospholamban: an insight into the mechanism of atrial electrical remodeling.

OBJECTIVES: We investigated the gene expression of calcium-handling genes including L-type calcium channel, sarcoplasmic reticular calcium adenosine triphosphatase (Ca(2+)-ATPase), ryanodine receptor, calsequestrin and phospholamban in human atrial fibrillation. BACKGROUND: Recent studies have demonstrated that atrial electrical remodeling in atrial fibrillation is associated with intracellular calcium overload. However, the changes of calcium-handling proteins remain unclear. METHODS: A total of 34 patients undergoing open heart surgery were included. Atrial tissue was obtained from the right atrial free wall, right atrial appendage, left atrial free wall and left atrial appendage, respectively. The messenger ribonucleic acid (mRNA) amount of the genes was measured by reverse transcription-polymerase chain reaction and normalized to the mRNA levels of glyceraldehyde 3-phosphate dehydrogenase. RESULTS: The mRNA of L-type calcium channel and of Ca(2+)-ATPase was significantly decreased in patients with persistent atrial fibrillation for more than 3 months (0.36+/-0.26 vs. 0.90+/-0.88 for L-type calcium channel; 0.69+/-0.42 vs. 1.21+/-0.68 for Ca(2+)-ATPase; both p < 0.05, all data in arbitrary unit). We further demonstrated that there was no spatial dispersion of the gene expression among the four atrial tissue sampling sites. Age, gender and underlying cardiac disease had no significant effects on the gene expression. In contrast, the mRNA levels of ryanodine receptor, calsequestrin and phospholamban showed no significant change in atrial fibrillation. CONCLUSIONS: L-type calcium channel and the sarcoplasmic reticular Ca(2+)-ATPase gene were down-regulated in atrial fibrillation. These changes may be a consequence of, as well as a contributory factor for, atrial fibrillation.

Risk factors for bacteraemia and endovascular infection due to non-typhoid salmonella: a reappraisal.

BACKGROUND: Endovascular infections are rare complications of non-typhoid salmonellosis. The diagnosis is frequently not established until the infection is advanced. It is important to identify high-risk patients and treat them as early as possible. AIM: To identify risk factors for bacteraemia and endovascular infection in patients with non-typhoid salmonellosis. DESIGN: Retrospective study. SETTING: A single tertiary-care hospital in Taiwan. METHODS: Data were collected by retrospective chart review. Log-logistic regression modelling was used to identify independent risk factors for bacteraemia and endovascular infection. We analysed the characteristics of patients with gastroenteritis vs. those with bacteraemia, and of bacteraemic patients with vs. without endovascular infection. RESULTS: Between 1984 and 2004, there were 373 adult cases of non-typhoid salmonellosis. There were 76 intestinal Salmonella infections, 290 bloodstream infections (including 47 endovascular infections), and 7 extra-intestinal non-bacteraemic infections. The independent positive predictors of bacteraemia were systemic lupus erythematosus, liver cirrhosis, HIV infection, and solid organ cancers. The only independent positive predictor of endovascular infection was atherosclerosis. The independent negative predictors of endovascular infection were solid organ cancers and immunodeficiency. DISCUSSION: Risk factors for atherosclerosis predisposed our patients with bacteraemia to endovascular infection. Although immunodeficiency predisposed patients to bacteraemia, it was associated with a low incidence of endovascular infection.