High dislocation density-induced large ductility in deformed and partitioned steels.

A wide variety of industrial applications require materials with high strength and ductility. Unfortunately, the strategies for increasing material strength, such as processing to create line defects (dislocations), tend to decrease ductility. We developed a strategy to circumvent this in inexpensive, medium manganese steel. Cold rolling followed by low-temperature tempering developed steel with metastable austenite grains embedded in a highly dislocated martensite matrix. This deformed and partitioned (D and P) process produced dislocation hardening but retained high ductility, both through the glide of intensive mobile dislocations and by allowing us to control martensitic transformation. The D and P strategy should apply to any other alloy with deformation-induced martensitic transformation and provides a pathway for the development of high-strength, high-ductility materials.

On the roles of graphene oxide doping for enhanced supercurrent in MgB2 based superconductors.

Due to their graphene-like properties after oxygen reduction, incorporation of graphene oxide (GO) sheets into correlated-electron materials offers a new pathway for tailoring their properties. Fabricating GO nanocomposites with polycrystalline MgB2 superconductors leads to an order of magnitude enhancement of the supercurrent at 5 K/8 T and 20 K/4 T. Herein, we introduce a novel experimental approach to overcome the formidable challenge of performing quantitative microscopy and microanalysis of such composites, so as to unveil how GO doping influences the structure and hence the material properties. Atom probe microscopy and electron microscopy were used to directly image the GO within the MgB2, and we combined these data with computational simulations to derive the property-enhancing mechanisms. Our results reveal synergetic effects of GO, namely, via localized atomic (carbon and oxygen) doping as well as texturing of the crystals, which provide both inter- and intra-granular flux pinning. This study opens up new insights into how low-dimensional nanostructures can be integrated into composites to modify the overall properties, using a methodology amenable to a wide range of applications.

Osmotic demyelination syndrome caused by normal saline correction in a patient admitted for gastric ulcer bleeding.

A 61-year-old male had osmotic demyelination syndrome caused by rapid correction of gastric ulcer bleeding and vomiting related hyponatraemia with normal saline. It is rare to see severe hyponatraemia caused by gastric ulcer bleeding and vomiting. Hypokalaemia may be the determinant predisposing factor. There was no specific brain image finding until 17 days after the initial clinical presentation of this disease. Brain diffusion weighted MRI series did not help for the early diagnosis in this case. Outcome of this case may be more favourable if we corrected his hyponatraemia with half-saline or other hypotonic saline and close monitored serum sodium level, and relowered with dextrose water and desmopressin once we observed that the correction rate of hyponatraemia was beyond the recommended rate.

Acute effect of ionic high osmolar contrast medium on renal antioxidant enzyme activity in streptozotocin-induced diabetic rats.

Acute contrast medium-induced nephrotoxicity was estimated in 3%-12% of patients receiving cardiac angiography, especially in advanced age, renal insufficiency and diabetic patients. As intrinsic renal antioxidant enzyme activities may play a crucial role in defence against renal oxidant injury, this study was designed to investigate the acute effect of ionic high osmolar diatrizoate meglumine/diatrizoate sodium on renal antioxidant activities in normal or streptozotocin (STZ)-induced diabetic rats at two time points (1 h and 24 h). A total of 40 Wistar rats were separated to normal and STZ-induced diabetic groups. Ten of each group were injected with diatrizoate (10 ml/kg) via tail vein and 10 with 10 ml/kg of 0.9% NaCl as control. This study shows that diabetic rats had higher renal glutathione peroxidase (GPx) activities than those of normal rats. GPx activities decreased significantly after diatrizoate injection at the first hour (717.4+/-104.0 to 578.6+/-92.1 mU/mg in the diabetic group, 466.4+/-30.6 to 371.4+/-75.5 mU/mg in the normal group, all P=0.032) but the difference faded 24 h later. The increase of superoxide dismutase (SOD) activities was enhanced (673.5+/-100.2 to 750.4+/-129.8 U/mg, P=0.04) in the normal group, but not in the diabetic group (624.1+/-156.6 to 671.1+/-136.7 U/mg, P=0.15) after diatrizoate injection at the first hour. At 24 h, renal SOD activities were still significantly higher in the diatrizoate injection group. In summary, intrinsic renal antioxidant activities are adapted in STZ-induced diabetes and ionic high osmolar diatrizoate could modify their activities. Furthermore, diabetics have abnormal response of renal antioxidant activities by contrast media and are at risk for contrast-mediated nephrotoxicity.

Follicular development and maturation in gilts selected for an index of high ovulation rate and high prenatal survival.

Seventy-one 10th-generation gilts from White Line-1 (WL-1 = randomly selected control line) and White Line-2 (WL-2 = selected for an index of ovulation rate and prenatal survival rate) were used to compare the pattern of follicular development and atresia during the follicular phase of the estrous cycle. Gilts were treated with PGF(2alpha)on d 13 of the estrous cycle (d 0 of induced follicular development) to induce luteolysis and assigned randomly within line and sire for ovary recovery on d 0, 2, 3, 4, 5, and the day after estrus. Ovaries were evaluated for numbers of corpora albicantia and small (2 to 2.9 mm), medium (M1 = 3 to 4.9 mm; M2 = 5 to 6.9 mm), and large (>or=7 mm) follicles. The concentration of estradiol-17beta in follicular fluid was used to classify individual M2 and large follicles as estrogen-active (>or=100 ng of estradiol-17beta/mL) or inactive (<100 ng of estradiol-17beta/mL). The WL-2 gilts had a greater ovulation rate than WL-1 gilts at their pre-treatment estrus (20.4 vs. 13.8 corpora albicantia; P < 0.001). The small and M1 follicle populations decreased rapidly in both lines over time (P < 0.001). The M2 follicle population increased in both lines between d 0 to 4 and then decreased. Mean estradiol concentration of M2 follicles increased in both genetic lines over time (P < 0.02). All large follicles were estrogen-active in both lines; the number of large follicles increased with day (P < 0.001) and was similar in both lines. The number of estrogen-active M2 follicles was similar in both lines, increasing to d 3 and 4 and then decreasing (P < 0.01) thereafter. However, the total number of estrogen-active follicles (sum of estrogen-active M2 and large follicles) was greater in WL-2 than in WL-1 gilts (P < 0.04), increasing to the ovulatory potential by d 3 in WL-1 gilts, but continuing to increase through d 4 in WL-2 gilts. Selection of an additional six ovulatory follicles from the estrogen-active M2 follicle pool after d 5 was required in both lines to achieve the projected ovulation rate, and after estrus, the number of large follicles remained insufficient to attain the ovulatory potential of each line.

Selective alterations in insulin receptor substrates-1, -2 and -4 in theca but not granulosa cells from polycystic ovaries.

The elevated insulin concentrations that occur in many women with polycystic ovary syndrome (PCOS) can contribute significantly to ovarian hyperandrogenism. The objective of the present study was to compare the content of proximal insulin signalling molecules in theca and granulosa cells between polycystic ovaries and regular cycling controls. Individual follicles (3-7 mm) were obtained from 11 women with PCOS and 10 regularly cycling control women. The theca and granulosa cells were microdissected from each follicle. Total protein was extracted and signalling proteins were measured by western blot analysis. There was no difference in insulin receptor content between PCOS and controls in either theca or granulosa cells. Insulin receptor substrate (IRS)-1 and -2 were increased (P<0.05), but IRS-4 was decreased (P<0.03) in PCOS theca cells. There were no changes in IRS-1, -2 or -4 in granulosa cells. IRS-3 was undetectable in all samples. There were no changes in phosphatidyl inositol-3 kinase catalytic subunits p110alpha or p110beta in either theca or granulosa cells. These data demonstrate cell-specific alterations in IRS protein concentrations in theca cells from polycystic ovaries that are consistent with an exaggerated amplification of the insulin signal and which may play an important role in ovarian hyperandrogenism and thecal hyperplasia.

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

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

Atrioventricular block in Kearns-Sayre syndrome: a case report.

The Kearns-Sayre (K-S) syndrome which includes the triad of progressive external ophthalmoplegia, pigment retinopathy, and disorder of cardiac conduction was first described in 1958. The mitochondria disorder is believed to be the cause of this syndrome. Involvement of the cardiac conduction system is the most importent prognostic factor in K-S syndrome. A 34-year-old male K-S syndrome patient, manifesting as ptosis and weakness of limbs since the age of 15 years, suffered from dizziness and weakness. Twelve-lead eletrocardiography (ECG) showed a 2:1 atrioventricular (AV) block with slow ventricular rate. Intermittent complete AV block, complete left bundle branch block and torsades de pointes were noted in Holter ECG. The electrophysiology study demonstrated prolonged HV interval (85 ms) on conduction beat and infra-His block on non-conduction beat. A VVIR mode of permanent pacemaker was implanted and the patient's condition was stable during this period of follow-up.

Effect of ionic and nonionic contrast media on fibrinolysis in patients undergoing angiocardiography.

Very few investigators have studied the effect of contrast media on fibrinolysis. The results of those previous studies are contradictory and inconclusive. The purpose of this study was to evaluate the effect of ionic and nonionic contrast media on fibrinolysis in patients undergoing angiocardiography. Sixty-two patients randomly received either ionic contrast medium Hypaque-76 (n = 31) or nonionic contrast medium Ultravist-370 (n = 31). Plasma tissue plasminogen activator (t-PA), plasminogen activator inhibitor 1 (PAI-1), fibrinogen, and D-dimer were measured before and 20 minutes after the procedures. A significant increase of PAI-1 levels was seen in the Ultravist group but not in the Hypaque group. The t-PA and fibrinogen levels remained virtually unchanged in both groups. A significant increase of D-dimer concentrations was observed in the Hypaque group but not in the Ultravist group. The results of this study may in part explain the reason that the ionic contrast media produce fewer thromboembolic complications than the nonionic contrast media during the cardiac catheterization.

Cystic left atrium myxoma--a rare case report.

Myxoma is the most common primary tumor of heart. The typical picture of myxoma under echocardiography is a solid, dense echo mass and left atrium is the most common site to find it. The cystic form of myxoma is vary rare. We report a patient who received echocardiographic examination under impression of mitral valve stenosis. A multilobulated cystic mass which was like a hydatid cyst was found in the left atrium and atrioventricular flow was affected by this mass. After tumor resection, myxoma with internal hemorrhage was proved by pathology. No further recurrent myxoma was found during follow-up echocardiographic examination.

The effect of fluvastatin on fibrinolytic factors in patients with hypercholesterolemia.

Several studies have shown cardiovascular benefit in treating hypercholesterolemia with HMG-CoA reductase inhibitor. However, in addition to the lowering of cholesterol, the beneficial effects of this inhibitor reflect other pharmacological activities. Whether these beneficial effects are partly mediated by changes in fibrinolytic factors remains to be proven, since clinical studies on the effects of HMG-CoA reductase inhibitors on fibrinolytic factors have not yielded consistent results. The purpose of this study was to evaluate the effects of fluvastatin on fibrinolytic factors in hypercholesterolemic patients. After 6 weeks on a low-fat, low-cholesterol diet, 23 outpatients known to have primary hypercholesterolemia with low density lipoprotein cholesterol (LDL-C) > or = 130 mg/dl with at least 2 risk factors or fasting LDL-C > or = 160 mg/dl were selected for the study. Venous blood samples were collected at baseline and at 8 weeks after fluvastatin therapy (40 mg/day) to measure of tissue plasminogen activator (t-PA), plasminogen activators inhibitor-1 (PAI-1), fibrinogen, D-dimer and lipid profile. After 8 weeks of therapy, fluvastatin reduced serum cholesterol by 11% (261.9 mg/dl vs 233.2 mg/dl, P < 0.01) and LDL-C by 22% (191.9 mg/dl vs 149.3 mg/dl, P < 0.01). D-dimer was significantly decreased (0.38 ng/L vs 0.28 ng/L, P = 0.02) and tPA, PAI-1 and fibrinogen tended to decrease after therapy. Fluvastatin therapy improved fibrinolytic profile; the result of this study may in part explain the benefit of HMG-CoA reductase inhibitor on cardiovascular system other than lipid lowering.

Human EZF, a Krüppel-like zinc finger protein, is expressed in vascular endothelial cells and contains transcriptional activation and repression domains.

Members of the erythroid Krüppel-like factor (EKLF) multigene family contain three C-terminal zinc fingers, and they are typically expressed in a limited number of tissues. EKLF, the founding member, transactivates the beta-globin promoter by binding to the CACCC motif. EKLF is essential for expression of the beta-globin gene as demonstrated by gene deletion experiments in mice. Using a DNA probe from the zinc finger region of EKLF, we cloned a cDNA encoding a member of this family from a human vascular endothelial cell cDNA library. Sequence analysis indicated that our clone, hEZF, is the human homologue of the recently reported mouse EZF and GKLF. hEZF is a single-copy gene that maps to chromosome 9q31. By gel mobility shift analysis, purified recombinant hEZF protein bound specifically to a probe containing the CACCC core sequence. In co-transfection experiments, we found that sense but not antisense hEZF decreased the activity of a reporter plasmid containing the CACCC sequence upstream of the thymidine kinase promoter by 6-fold. In contrast, EKLF increased the activity of the reporter plasmid by 3-fold. By fusing hEZF to the DNA-binding domain of GAL4, we mapped a repression domain in hEZF to amino acids 181-388. We also found that amino acids 91-117 of hEZF confer an activation function on the GAL4 DNA-binding domain.

Double mycotic aneurysms of the ascending aorta.

Infection in the vascular tree has been proved to be one of the greatest challenges for cardiovascular surgeons. Of these, mycotic aneurysms of the ascending aorta were considered to be almost always lethal until recently. A thorough survey of the literature indicates that only 42 cases of mycotic aneurysm of the ascending aorta have been reported. All the reported cases of mycotic aneurysm of the ascending aorta were a single lesion in the ascending aorta except a case reported in 1993. This report describes an additional case of double mycotic aneurysms of the ascending aorta caused by Pseudomonas infection.

The use of right gastroepiploic artery for the bypass of left anterior descending coronary artery--case reports.

The right gastroepiploic artery (RGEA), a branch of the gastroduodenal artery, supplies the greater curvature of the stomach. It is capable of easily reaching the posterior and lateral surface of the heart as a reliable arterial conduit when appropriately harvested. In the previous reports, it has usually been anastomosed to the right coronary artery (RCA) or left circumflex coronary artery (LCX). Here, we present two cases of ischemic heart disease undergoing coronary revascularization. The RGEA was anastomosed to the left anterior decending coronary artery (LAD), which is the most important coronary artery in terms of patient outcome. Thallium-201 myocardial scintigraphy has proven that the RGEA can provide sufficient blood flow to the territory of the LAD. Thus, in coronary artery bypass grafting (CABG), the RGEA is a reliable arterial conduit for LAD revascularization.

Sick sinus syndrome with normal atropine response--a case report.

A 76-year-old woman was admitted due to recurrent syncope. Sinus bradycardia and intermittent sinus pauses (up to 2.24 sec) were documented by 24 hour Holter electrocardiogram. Although intravenous atropine can increase the sinus rate up to 100 bpm, electrophysiologic study showed marked prolongation of sinus node recovery time both at the control state and after autonomic blockades. Sick sinus syndrome was diagnosed, even with a normal atropine test, and a permanent pacemaker resulted in resolution of the syncope.

Efficacy and safety of radiofrequency catheter ablation for paroxysmal supraventricular tachycardias.

From January 1992 to June 1993, 100 consecutive patients with clinically documented paroxysmal supraventricular tachycardias underwent radiofrequency catheter ablation. Group 1 consisted of 46 patients (male:female = 9:37, age: 46 +/- 13 years) with slow-fast atrioventricular nodal reentrant tachycardia. Radiofrequency current was aimed at the slow pathway area which was identified by both anatomical and electrophysiological methods. A mean application of 8 +/- 9 was delivered at a mean power of 22 +/- 4 watts with a mean duration of 21 +/- 3 seconds. Selective ablation of slow pathway conduction was achieved in 28 patients and modification of slow pathway conduction in 12 patients. Antegrade fast pathway conduction was ablated in 3 patients, and retrograde fast pathway conduction in 1. Mean peak CPK was 156 +/- 117 IU/L after ablation. Neither AV block nor clinical recurrence was found during 9.7 +/- 5.1 months follow up. Group 2 consisted of 54 patients with accessory pathway (AP) mediated atrioventricular reciprocating tachycardia. For 35 patients (M:F = 21:14, age: 40 +/- 12 years) who had left-sided accessory pathway, catheter ablation was approached by the retrograde trans-aortic technique in 33 patients and by the transseptal left atrial approach through patent foramen ovale in 2 patients. The mean energy delivered was 28 +/- 5 watts for a duration of 27 +/- 12 sec and 9 +/- 8 applications. The accessory pathway conduction was successfully ablated in 30 patients (86%). Mean peak CPK was 392 +/- 534 IU/L. Cardiac tamponade occurred in 1 patient and transient cerebral ischemia in another, but without mortality. No clinical recurrence was found during 9 +/- 4 months follow-up. Nineteen patients (M:F = 7:12, age: 36 +/- 11 years) had right-sided AP. The mean energy required for successful ablation was 30 +/- 4 watts for a duration of 35 +/- 15 sec and 12 +/- 9 applications. Mean peak CPK was 147 +/- 70 IU/L. Clinical recurrence occurred in 3 patients (15.8%), 1 of them had subsequent successive ablation. The overall immediate procedure success rate for right-sided AP was 65%. In conclusion, radiofrequency catheter ablation is a safe and effective treatment modality for patients with paroxysmal supraventricular tachycardias.

The circadian variations of blood pressure and heart rate in patients with mitral valve prolapse.

It is well known that both normal subjects and hypertensives manifest a distinct nocturnal fall of arterial blood pressure and heart rate. But till now there has been no report about the diurnal change of blood pressure and heart rate in MVP patients. In this report we studied the circadian variations of blood pressure and heart rate in 18 symptomatic MVP patients (mean age 32 +/- 10 years) and compared them with those in 18 age- and sex-matched normal control subjects (mean age 35 +/- 9 years). The MVP group presented a statistically significant blunting of the nocturnal fall in systolic blood pressure (4.2 +/- 3.6% vs 9.7 +/- 3.7%, p = 0.0002). No obvious difference in the nocturnal fall in heart rate was noted between both groups (20.2 +/- 6.0% vs 18.8 +/- 5.6%, p = 0.4290). In conclusion, the circadian variation of blood pressure was blunted in patients with mitral valve prolapse. The mechanism is uncertain and further studies are necessary to clarify it.

Cardiac amyloidosis--a case report.

A 52-year-old male patient presented with resistant congestive heart failure. Echocardiographic findings revealed increased right ventricular (RV) wall thickness in conjunction with concentric left ventricular (LV) hypertrophy, LV systolic dysfunction and a granular sparking myocardial appearance. Doppler assessment showed a restrictive LV and RV diastolic filling pattern. These echocardiographic features combined with low voltage of the electrocardiogram is highly suggestive of cardiac amyloidosis. The diagnosis was confirmed by cardiac catheterization and endomyocardial biopsy.

Effect of ionic contrast medium on plasma atrial natriuretic peptide.

To evaluate the effect of ionic contrast medium on plasma atrial natriuretic peptide (ANP) and its contributing factors, we measured plasma ANP, serum osmolality, pulmonary capillary wedge pressure (PCWP), femoral artery systolic pressure (FASP), and heart rate before and after left ventriculography with Rayvist in 13 patients suspected of coronary artery disease. The control values of plasma ANP, serum osmolality, and PCWP were 20.3 +/- 5.1 pg/ml, 293.5 +/- 1.5 mosm/kg, 6.6 +/- 0.8 mm Hg, respectively. Rayvist produced a significant increase in plasma ANP, serum osmolality, and PCWP at 1 minute (26.0 +/- 6.3 pg/ml, p < 0.05; 300.7 +/- 1.9 mosm/Kg, p < 0.001; 10.7 +/- 1.3 mm Hg, p < 0.001) and 5 minutes (27.3 +/- 6.3 pg/ml, p < 0.01; 296.8 +/- 1.9 mosm/Kg, p < 0.001; 10.4 +/- 1.7 mm Hg, p < 0.01) post left ventriculography. The FASP decreased significantly at 1 minute, followed by an insignificant increase at 5 minutes. The heart rate increased significantly at 1 minute but no significant change was noted at 5 minutes. We conclude that plasma ANP increases significantly after left ventriculography with Rayvist and its response may be related to left ventricular filling pressure and serum osmolality, but not to FASP or heart rate.