Recurrent asystoles associated with vasovagal reaction during venipuncture

A 17-year-old high school student presented with a history of habitual faintings. On 24-hour Holter monitoring, cardiac asystoles were recorded, the longest lasting approximately 7 or 8 seconds during venipuncture procedures. The asystole associated with venipuncture demonstrated the cardioinhibitory effects of vasovagal reaction with blood-injury phobia. He also had a positive response during head-up tilt test showing hypotension and relative bradycardia after intravenous isoproterenol injection. After administration of oral beta blocker, he did not show further or recurrent cardiac asystole during blood injury procedure on electrocardiographic examination. Venipuncture is the most common invasive medical procedure performed in hospital settings. While venipuncture is considered to be reasonably safe, serious complication may occur even when only a small volume of blood is withdrawn. Therefore, medical personnel should be prepared to provide appropriate care.

Viability evaluation of engineered tissues

Biohybrid artificial organs encompass all devices capable of substituting for an organ or tissue function and are fabricated from both synthetic materials and living cells. The viability of engineered tissue could be related to the viability of implanted cells. The system of viability assay for mammalian cell culture can be applied to the determination of cell viability for engineered tissue. This review explores various methods of cell viability assay which can be applied to the viability evaluation of engineered tissue. The major criteria employed in viability assays include survival and growth in tissue culture, functional assay, metabolite incorporation, structural altercation, and membrane integrity. Each viability assay method is based on different definitions of cell viability, and has inherent advantages and disadvantages. In order to be able to assess the viability of cells with one assay method, it is desirable to compare the viability measurements from various assays derived from different criteria.

Heparinized bovine pericardium as a novel cardiovascular bioprosthesis

A novel chemical modification of biological tissues was developed by the direct coupling heparin to bovine pericardium (BP). The heparinization involves pretreatment of BP using GA and followed by grafting heparin to BP by the reaction of residual aldehyde and amine group of heparin. BP was modified by direct coupling of heparin and the effect of heparin coupling on calcification was evaluated in vitro and in vivo. Heparinized BP was characterized by measuring shrinkage temperature, mechanical properties, digestion resistance to collagenase enzyme, in vitro cytotoxicity, and in vivo calcification. Thermal and mechanical properties showed that the durability of heparin-treated tissue increased as compared with fresh tissue and GA-treated tissue. Resistance to collagenase digestion revealed that heparin-treated tissue has greater resistance to enzyme digestion than did fresh tissue and GA-treated tissue. Heparinized tissue had shown to be non-cytotoxic, however, relatively high cytotoxicity was observed in the GA-treated tissues due to the release of GA. In vivo calcification study demonstrated much less calcium deposition on heparin-treated BP than GA-treated one. Obtained results attest to the usefulness of heparinized BP for cardiovascular bioprostheses.

Successful management of intractable coronary spasm with a coronary stent

Although the long-term survival of patients suffering from coronary spasm is usually excellent, serious complications can develop, such as disabling pain, myocardial infarction, ventricular tachyarrhythmias, atrioventricular block and sudden cardiac death. A 40-year-old man who had intractable chest pain from coronary artery spasm suffered ventricular fibrillation and an acute anterior myocardial infarction upon first admission. The patient underwent a coronary angiogram, which revealed a spontaneous focal spasm at the proximal left anterior descending coronary artery (LAD). He was treated by the combination of nitrate and calcium channel blocker, but continued to complain of severe chest pain despite intensive medical therapy and he had to be treated in the emergency room 5 times during an 8-month follow-up period. An ergonovine coronary angiogram was performed and an intracoronary ultrasound examination, which revealed a focal spasm at the same site of the proximal LAD with a small amount of localized eccentric atheromatous plaque. A coronary artery stent was placed in the proximal LAD and his symptoms resolved. A follow-up coronary angiogram was performed 3 years after stenting and the stent remained patent without any in-stent restenosis or spasm.

Specific determination of endothelial cell viability in the whole cell fraction from cryopreserved canine femoral veins using flow cytometry

Abstract: An efficient method for specifically determining the viability of endothelial cells (EC) from cells dissociated from the human saphenous vein was investigated. Three different methods, trypan blue staining assay, [3H]-proline incorporation assay, and flow cytometry (FCM), combined with the fluorescein isothiocyanate conjugated with Griffonia simplicifolia agglutins (GS1-FITC)/propidium iodide (PI) double staining, were used. Both trypan blue staining and [3H] proline incorporation assays demonstrated less sensitivity to determine viability of EC differentially from the other cells. FITC-GS1 showed prominent binding to the vascular EC and could be counted by FCM including PI on dead cells. Following the cryopreservation process, the GS1-FITC/PI FCM analytical method was adopted to test simultaneously the viability of whole cells and EC from the same tissue, human saphenous veins, and mongrel dogs' femoral veins after harvesting, antibiotic solution treatment, and thawing. The viability of the whole cells from veins decreased with a significant difference (p < 0.05) from that of EC after thawing.

Viability of cells in cryopreserved canine cardiovascular organs for transplantation

To determine applicability of the cryopreservation procedure for vessel grafts, the viability of endothelial cells (ECs) among the whole cells in three kinds of organs artery, vein, trachea in mongrel dogs was evaluated on the basis of histological analysis. The Griffonia simplicifolia agglutins-fluorescein isothiocyanate (GSA-FITC) and propidium iodide (PI) double staining methods were combined with flow cytometry (FCM), which was able to simultaneously determine the viability of whole cells and ECs from the same tissue, were performed after harvesting, after antibiotic solution treatment, and after cryopreservation and thawing. In most cases, the viability of ECs is lower than that of whole cells from veins and arteries. The viability of whole cells in veins was maintained until the antibiotic solution treatment and then decreased significantly after cryopreservation and thawing, while the ECs began to decrease significantly after the antibiotic solution treatment and more markedly decreased after thawing. The viability of ECs and whole cells from arteries was similar to that of the veins' conditions. The viability of whole cells from the trachea decreased with a similar pattern to that of the ECs from vessels. In consideration of maintaining cell viability among the three kinds of organs, the viability of arteries was better than that of the others. The cells in the trachea demonstrated a lower viability than the vessels. The effect of antibiotic solution treatment on the reduction of cell viability depends on the treatment time and temperature.

Anuran metamorphosis: a model for gravitational study on motor development

Limbs and supporting structures of an organism experience a full weight of its own when it lands from water, because neutral buoyancy in the aquatic habitat will be no longer available in the terrestrial world. Metamorphosis of anuran amphibians presents a good research model to examine how this transition from non-loading to weight-loading affects development of motor capacity at the time of their first emergence on land. Our video analysis of the transitional anurans, Rana catesbeiana, at Gosner stage 46 (the stage of complete transformation) demonstrated that the take-off speed increased 1.23-fold after the first six hours of weight-loading on the wet ground. It did not increase further during the following three days of loading, and was close to the level of mature frogs with different body mass. During development of larvae in deep water with no chance of landing through metamorphosis, both tension and power of a hindlimb anti-gravity muscle increased 5-fold between stages 37 and 46. However, the muscle contractility increased more rapidly when the larvae could access the wet ground by their natural landing behavior after stages 41-42. Muscle power, one of major factors affecting locomotory speed, was 1.29-fold greater in the loaded than in the non-loaded larvae at the transitional stage. Thus, weight-loading had a potentially significant effect on the elevation of motor capacity, with a similar extent of increment in locomotory speed and muscle power during the last stages of metamorphosis. Such a motor adjustment of the froglets in a relatively short transitional period would be important for effective ecological interactions and survival in their inexperienced terrestrial life.

A bone replaceable artificial bone substitute: morphological and physiochemical characterizations

A composite material consisting of carbonate apatite (CAp) and type I atelocollagen (AtCol) (88/12 in wt/wt%) was designed for use as an artificial bone substitute. CAp was synthesized at 58 degrees C by a solution-precipitation method and then heated at either 980 degrees C or 1,200 degrees C. In this study, type I AtCol was purified from bovine tail skins. A CAp-AtCol mixture was prepared by centirfugation and condensed into composite rods or disks. The scanning electron-microscopic (SEM) characterization indicated that the CAp synthesized at 58 degrees C displayed a crystallinity similar to that of natural bone and had a high porosity (mean pore size: about 3-10 microns in diameter). SEM also revealed that the CAp heated at 980 degrees C was more porous than that sintered at 1,200 degrees C, and the 1,200 degrees C-heated particles were more uniformly encapsulated by the AtCol fibers than the 980 degrees C-heated ones. A Fourier transformed-infrared spectroscopic analysis showed that the bands characteristic of carbonate ions were clearly observed in the 58 degrees C-synthesized CAp. To enhance the intramolecular cross-linking between the collagen molecules, CAp-AtCol composites were irradiated by ultraviolet (UV) ray (wave length 254 nm) for 4 hours or vacuum-dried at 150 degrees C for 2 hours. Compared to the non cross-linked composites, the UV-irradiated or dehydrothermally cross-linked composites showed significantly (p < 0.05) low collagen degradation and swelling ratio. Preliminary mechanical data demonstrated that the compressive strengths of the CAp-AtCol composites were higher than the values reported for bone.

Autoimmune hepatitis in a patient with myasthenia gravis and thymoma--a report on the first case in Korea

Myasthenia gravis is an autoimmune disease that results from an antibody-mediated reaction and occurs with thymoma in 15% of patients. It is very rarely associated with autoimmune hepatitis. Four cases of myasthenia gravis with autoimmune hepatitis have been reported in the world. We recently experienced a case of 30-year-old man with myasthenia gravis associated with thymoma and autoimmune hepatitis. This condition is the first case that has not been reported previously in Korea. We report this rare condition along with a brief review of the literature.

Calcification of leaflets from porcine aortic valves crosslinked by ultraviolet irradiation

Glutaraldehyde (GA)-pretreated porcine aortic valves are generally used as a bioprosthetic valve, but gradual calcification of the leaflets often occurs. It has been hypothesized that the crosslinking agent, GA, stabilizes and perhaps modifies phosphorus-rich calcifiable structures in the bioprosthetic tissue. This is supported by our findings that calcium deposition is induced rapidly in GA-pretreated leaflets in comparison with ultraviolet (UV) irradiated leaflets. After 3 days of in vitro calcification test, calcium levels were 257.6 +/- 23.5 microg/cm3 in GA-pretreated, 57.7 +/- 10.2 microg/cm3 in the control, and 108.6 +/- 7.6 microg/cm3 in 24 h UV irradiated leaflets. The calcium level in all test groups increased as time proceeds and the calcium level of GA-pretreated leaflets was significantly higher than the control and UV irradiated leaflets during test. This rapid calcium deposition on the GA-pretreated leaflets may be due to residual aldehyde groups after pretreatment. The exposure time of UV irradiation was not significantly correlated with the extent of calcification. After 14 days of the test, calcium levels in leaflets UV irradiated for 1, 2, 4, and 24 h were 502.6 +/- 12.3 microg/cm3, 547.5 +/- 34.1 microg/cm3, 564.3 +/- 26.1 microg/cm3, and 543.0 +/- 55.5 microg/cm3. In all test groups, [Ca]/[P] molar ratio decreased toward that of hydroxyapatite as the predominant mineral phase as time proceeds. This study suggests that UV irradiation can be considerable as an efficient crosslinking method to surmount the side effects induced by GA-pretreatment and may endow tissue with mechanical property.

Predictive factors for the second restenosis after coronary interventions

One of the major limitations in coronary intervention is restenosis. This study was aimed to identify clinical, angiographic, and procedural factors that may be related to the second restenosis (SR). We studied 101 patients who underwent more than two follow-up coronary angiograms after two coronary interventions between January 1996 and December 1998 in Chonnam University Hospital (out of 4,092 total coronary interventions in 3,030 patients during the same period). The patients were divided into two groups according to the evidence of SR. Fifty-two patients (group A: 57+/-10 years, M:F = 44:8) who had SR and the other 49 patients (group B: 54+/-9 years, M:F = 44:5) without SR were analyzed. Clinical features, angiographic characteristics, coronary interventional procedures, and other risk factors were compared between two groups by univariate analysis and multivariate stepwise logistic regression analysis was performed for the predictive factors for SR. The clinical variables of age, sex, clinical diagnosis, and risk factors were not different between two groups. The lesion severer than B(2) by AHA/ACC classification were associated with SR (P<0.05). Recurrent angina as an indication for follow-up angiography was associated with SR (P<0.01). Predictive factors associated with SR were patient's subjective symptom and lesion severer than type B(2) according to AHA/ACC classification.

A novel in vitro assessment of tissue valve calcification by a continuous flow type method

A dynamic flow type testing to study calcification was self-designed to investigate calcification in bioprosthetic heart valves. The apparatus consists of a container into which leaflets from a porcine aortic valve are placed, a chamber that contains calcium solution, and a peristaltic pump that provides a continuous supply of the solution toward the container. Efficacy of the apparatus was compared with the conventional batch type calcification testing at 37 degrees C through measuring the amount of calcium and phosphate deposited by inductively coupled plasma (ICP) and scanning electron microscope (SEM). After 14 days, calcium levels detected from the calcified deposit on leaflets were 470.4 +/- 37.0 microg/cm3 in the flow type testing whereas in the batch type testing levels were 81.0 +/- 6.7 microg/cm3. Though the calcium level on the leaflet increased as the exposure time to calcium solution increased in both testings, the rate and the tendency of calcification could be assessed very rapidly by flow type testing in comparison with batch type testing. [Ca]/[P] molar ratio decreased over time, and after 14 days, the ratio was close to 1.83 +/- 0.18 in the flow type testing. The ratio could not be determined in the batch type testing because the deposit was too small to assess. The descending rate of [Ca]/[P] molar ratio demonstrates that deposited calcium-complex at the earliest stage may interact with inorganic phosphate ions to create a calcified deposit mineral precursor. This in vitro dynamic flow type calcification testing was a favorable tool for rapid investigation of calcification.

Preclinical evaluation of prototype products

Preclinical evaluation of medical devices (prototype products) offers the opportunity to investigate and study the intended use of device materials. Preclinical evaluation programs are designed to determine the efficacy, safety, and biocompatibility of biomaterials, prostheses, and medical devices. The purpose of safety testing is to determine if a material presents potential harm to the human; it evaluates the interaction of the material with the in vivo environment and determines the effect of the host on the implant. Preclinical evaluation is the determination of the ability of the prototype product to perform with appropriate host response in a specific application, considered from the perspective of human clinical use. Therefore, preclinical data should include materials science and engineering, biology, biochemistry, medicine, host reactions and their evaluation, the testing of biomaterials, and the degradation of materials in a biological environment.

Preventive effects of the heparin-coated stent on restenosis in the porcine model

The coronary stent reduces acute coronary arterial occlusion and late restenosis during and after coronary intervention. However, stent thrombosis and restenosis are still major limitations in the widespread use of the coronary stent. Local drug delivery using the heparin-coated stent may be a new approach, which reduces the incidence of stent thrombosis and restenosis. In order to evaluate the effects of the heparin-coated stent on stent restenosis, heparin-coated stents were compared with control stents in a porcine coronary stent restenosis model. Stent overdilation injury (stent:artery = 1.3:1.0) was performed with bare Wiktor stents (group I, n = 10) and heparin-coated Wiktor stents (group II, n = 20; HEPAMED, Medtronics) in porcine coronary arteries. Follow-up quantitative coronary angiography (QCA) was performed at 4 weeks after stenting, and histo-pathologic assessments of stented porcine coronary arteries were compared in both groups. On QCA, percent diameter stenosis was significantly higher in group I than in group II (16.3% +/- 6.62% vs. 9.6% +/- 5.06%, P < 0.05). The injury score of stented porcine coronary arteries was the same in both groups (1. 26 +/- 0.23 vs. 1.20 +/- 0.22). The area of pathologic stenosis of the stented arteries was higher in group I than in group II (41.6% +/- 12.5% vs. 27.1% +/- 9.9%, P < 0.005). The neointimal area was higher in group I than in group II (4.58 +/- 1.41 mm(2) vs. 2.57 +/- 1.07 mm(2), P < 0.05). By immunohistochemistry, the proliferating cell nuclear antigen (PCNA) index was higher in group I compared with group II (11.2% +/- 6.75% vs. 6.3% +/- 4.14%, P < 0.05). The heparin-coated stent is effective in the prevention of late coronary stent restenosis in a porcine coronary stent restenosis model. This may be related to the inhibition of neointimal cell proliferation.

A case of prominent epicardial fat mimicking a tumor on echocardiography

Epicardial fat may anteriorly produce an echo-free space that can be mistaken for pericardial fluid. We recently experienced a 67-year-old woman with prominent epicardial fat which was presented as an echogenic tumor-like mass. She underwent open pericardiostomy to relieve large amount of pericardial effusion. Operative findings revealed only prominent epicardial fat. Biopsy of the pericardial and fat tissues revealed an inflammation and normal fat cells without any malignant cell infiltration.

Myocardial infarction with Moyamoya disease and pituitary gigantism in a young female patient

Myocardial infarction is very rare in young female patients with systemic vascular disorders. Moyamoya disease is a cerebrovascular disease associated with an abnormal vascular network. This report presents a 19-year-old female patient who suffered from chest pain and exertional dyspnea for 2 months prior to admission. She had a history of Moyamoya disease and pituitary gigantism since childhood. Her ejection fraction on echocardiogram was 20% and a perfusion defect with partial reversibility in the anterior wall was demonstrated on stress single photon emission computed tomography (SPECT). Diagnostic coronary angiogram revealed critical stenosis in the middle left anterior descending artery, which was treated by coronary stenting. Her subjective symptoms were relieved and the perfusion defect seen on SPECT decreased after coronary intervention.

Viability and enzymatic activity of cryopreserved porcine heart valve

Fibroblast viability of a natural tissue valve for replacing a defective heart valve through allograft or xenograft has been suggested to affect its clinical durability. In this study, the cell viability and enzymatic activity of porcine heart valve leaflets were examined in regard to concerning to the preservation process [variable warm ischemic time (WIT), cold ischemic time (CIT), and cryopreservation]. Porcine heart enblocs were obtained and valve dissection was performed after 2, 12, 24, or 36 hours, in respective groups A, B, C, and D, as WIT. Each group was stored for 24 hours as CIT and cryopreserved. Leaflets were dissected from a valved conduit after each process, and cell viability and enzymatic activity in the leaflet were investigated using trypan blue staining and API ZYM kits. WIT extension significantly decreased fibroblast viability (p < 0.05, 92.25 +/- 2.7% at 2 hours, 84.9 +/- 6.7% at 12 hours, 57.0 +/- 10.2% at 24 hours, 55.9 +/- 7.9% at 36 hours), while CIT for 24 hours was also influenced significantly (p < 0.05), whereas cryopreservation demonstrated no effect on cellular viability. In enzyme activity observation, several enzymes related to lipid or nucleotide degradation (esterase, esterase lipase, particularly phosphatase, phosphohydrolase) were remarkably changed following the valve-fabrication process. After 24 hours CIT, these enzymatic activities in groups B, C and D significantly increased, but the activities decreased after cryopreservation. Particularly, both the viability and enzymatic activity showed remarkable changes after CIT in group B (WIT = 12 hours). These results suggest that WIT is more important than CIT in maintaining viability of the valve, and that completing all the cryopreservation process within 12 hours after acquisition is recommended.

Evaluation of the degree of cross-linking in UV irradiated porcine valves

A porcine heart valve was irradiated by Ultraviolet (UV) rays (10 W, 254 nm) for 2, 4, 8 and 24 hours at 4 degrees C to cross-link the structural collagen matrix. The degree of cross-linking was evaluated by assaying the released amount of hydroxyproline (Hyp) from the matrix, and comparing it with the positive controls of valves treated by glutaraldehyde (GA) solution (0.625 wt%) and the negative controls of non-treated fresh valves. The undigested weight ratio of the specimens increased by increasing the UV irradiation time. The undigested weight of the leaflets, tunica interna and tunica externa of the fresh, GA-treated and UV-irradiated specimens after collagenase digestion was compared. As UV irradiation increased, the amount of released hydroxyproline was gradually decreased until 8 hours of irradiation, after which the released hydroxyproline-reduction occurred slightly until 24 hours of irradiation time in this system. A total 47.68% of the hydroxyproline in the valve was cross-linked by UV irradiation after 24 hours, while 73.74% of the hydroxyproline in the positive control was crossed-linked. Light microscopic observation revealed that the typical crimp pattern of collagen fibers decreased and was rearranged into a dense flattened pattern as the UV irradiation induced interfibrilar cross-linking. GA-treated valves demonstrated a denser matrix pattern than the UV-irradiated specimens. Cross-linked collagenous tissue prepared by UV irradiation would be useful for improving durability and reducing the disadvantages related to using a chemical cross-linking agent.

Antioxidant flavonoids and chlorogenic acid from the leaves of Eriobotrya japonica

The antioxidant activity of Eriobotrya japonica was determined by measuring the radical scavenging effect on DPPH (1,1-diphenyl-2-picrylhydrazyl) radical and lipid peroxidation produced when mouse liver homogenate was exposed to the air at 37 degrees C, using 2-thiobarbituric acid (TBA). The methanol extract and its fractions of Eriobotrya japonica leaves showed strong antioxidant activity. The antioxidant activity of EtOAc and n-BuOH soluble fractions were stronger than the others, and were further purified by repeated silica gel, MCl gel CHP-20P, and Sephadex LH-20 column chromatography. Antioxidant chlorogenic acid, quercetin-3-sambubioside from n-BuOH fraction, and methyl chlorogenate, kaempferol- and quercetin-3-rhamnosides, together with the inactive ursolic acid and 2 alpha-hydroxyursolic acid from EtOAc fraction were isolated. Antioxidant flavonoids and chlorogenic acid also showed prominent inhibitory activity against free radical generation in dichlorofluorescein (DCF) method.

The effects of antiplatelet agents in the prevention of ventricular tachyarrhythmias during acute myocardial ischemia in rats

Experiments were performed in rat models to study the effectiveness of various antiplatelet agents in the prevention of ventricular tachyarrhythmias during acute myocardial ischemia. The time to the onset of ST-segment elevation and initiating ventricular arrhythmias, frequency and incidence of ventricular arrhythmias, and mortality rates were observed during acute myocardial ischemia (20 minutes) induced by ligation of the proximal left anterior descending coronary artery (LAD) in anesthetized rats. Four groups were studied: Control group (n = 10, not pretreated); Aspirin pretreated group (n = 10, 300 mg/kg p.o. for 1 wk); Ticlopidine pretreated group (n = 10, 200 mg/kg p.o. for 1 wk); and Abciximab (Platelet glycoprotein IIb/IIIa receptor antagonist) pretreated group (n = 10, 2 mg/kg i.v. 10-20 minutes before an experiment). No significant difference was observed in the time to the onset of ST-segment elevation and ventricular arrhythmias between the groups. The incidence of ventricular tachycardia (VT) in the abciximab group was significantly lower than in the control group (p < 0.05) and ventricular fibrillation (VF) in the aspirin and ticlopidine group was significantly lower than in the control group (p < 0.05). The mortality rate in the ticlopidine group was significantly lower than in the control group (p < 0.01). This study suggests aspirin, ticlopidine, and abciximab can effectively prevent VT or VF during acute myocardial ischemia induced by nonthrombotic occlusion and its antiarrhythmic effect may lead to prolonged survival.

Radiofrequency catheter ablation in familial paroxysmal supraventricular tachycardia due to accessory atrioventricular pathways

Radiofrequency catheter ablation (RF-CA) has been widely used to cure paroxysmal supraventricular tachycardia (PSVT). However, its use has never been reported in familial PSVT caused by an accessory atrioventricular pathway (AP), which is known as one of the typical familial cardiovascular diseases. Two cases of using RF-CA for familial PSVT due to APs are presented, in a brother and sister, supporting a potential genetic role in the developmental failure to lose the atrioventricular connection during fetal life. The sister, a 24-year-old woman, had intermittent episodes of palpitation accompanied by chest pain for 2 years. An electrophysiologic study (EPS) confirmed her clinical tachycardia was atrioventricular reentrant tachycardia (AVRT) due to a left lateral concealed AP, which was subsequently successfully ablated with RF-CA. The brother, a 22-year-old man, had a 5-year history of paroxysmal palpitation. A resting electrocardiogram showed a right bundle branch block and left axis deviation with a delta wave. During his EPS, AVRT was reproducibly induced and a manifest AP was localized and then ablated at the left posteroseptal site, resulting in disappearance of the delta wave. PSVT, however, recurred 1 month later and during a repeat EPS the tachycardia was proved to be AVRT due to a right anterior concealed AP. The right anterior AP was successfully ablated with RF-CA. Both patients remained asymptomatic for more than 3 years following the successful ablation procedures.

A case of AV reentrant tachycardia due to a concealed accessory pathway with retrograde conduction manifested by isoproterenol

Retrograde conduction of the concealed accessory pathway (AP) is a prerequisite for the induction of atrioventricular reentrant tachycardia (AVRT). In patients with AVRT due to a concealed AP, the absence of retrograde conduction of the AP in the baseline state has rarely been reported. We report a case of AVRT due to a concealed left lateral AP, in which the retrograde conduction was absent in the baseline state and manifested by isoproterenol infusion. A 61-year-old man had suffered from intermittent palpitation for 17 years. A narrow QRS complex tachycardia with a retrograde P wave in the ST segment was recorded in 24-h Holter monitoring. An electrophysiologic study was performed while he was in a nonsedated state. No ventriculoatrial conduction over either the normal atrioventricular conduction system or the AP was demonstrated in the baseline state. Isoproterenol was infused at a rate of 1.0 microg/min. Retrograde conduction over the AP became manifest and AVRT was induced. The AP was ablated with radiofrequency energy at the left free wall. After ablation of the AP, no tachycardia was induced. To the authors'best knowledge, only 1 other similar case has been reported in the literature.

Effects of extracellular matrix constituents on the attachment of human oral epithelial cells at the titanium surface

This in vitro study attempts to delineate the role of extracellular matrix (ECM) constituents at the epithelial tissue-implant interface. To know which ECM constituents have a beneficial influence on the behavior of epithelial cells, the attachment, proliferation, morphologic pattern, and differentiation or cytoskeletal organization of human oral epithelial cells on ECM-coated (type IV collagen, fibronectin, type I collagen, laminin, and vitronectin) and noncoated titanium surface have been evaluated and compared. In each experiment comparing commercially pure titanium and oxygen plasma-cleaned titanium, the same ECM constituents were used. In this study, type IV collagen could provide an excellent substratum for epithelial cell attachment on titanium surface, but vitronectin-coated titanium revealed lower effectiveness for attachment of epithelial cells than noncoated titanium. These results suggested that type IV collagen could be used as a means for obtaining good epithelial seal, whereas vitronectin could be used to restrain the attachment of epithelium to dental implants.

Regenerative ability of somatic single and multiple embryos from cotyledons of Korean ginseng on hormone-free medium

Cotyledon explants of Korean ginseng (Panax ginseng C. A. Meyer) produced somatic embryos directly on growth regulator-free medium. Somatic embryos developed as either multiple or single-state forms, depending on the degree of maturity of the cotyledons. Cotyledon explants from midmature zygotic embryos formed multiple embryos, while cotyledons from fully mature zygotic embryos formed single embryos. Somatic single embryos regenerated into normal plantlets with both roots and shoots, while multiple embryos did not produce roots but regenerated only into multiple shoots. In full-strength MS basal medium, the root growth of plantlets derived from single embryos was weak compared to that of shoots. Deletion of ammonium nitrate from the MS medium promoted the root growth of the plantlets. The ginseng plants with well-developed shoots and roots regenerated from single embryos were successfully acclimatized in a greenhouse when they were planted in soil.

Atrial fibrillation in patients with permanent VVI pacemakers: risk factors for atrial fibrillation

OBJECTIVES

Atrial fibrillation (AF) does not only deteriorate the cardiac function and increases the thromboembolic risk but also triggers rapid and irregular ventricular rhythm in patients with atrial synchronous pacing. However, the risk factors for the development of AF in patients with pacemakers are not clearly determined yet. The present study was designed to determine the risk factors for AF in patients with VVI pacemakers.

METHODS

This study included 80 patients (41 sick sinus syndrome, 39 AV block) who were followed for more than 6 months or developed AF regardless of the duration of follow-up after implantation of VVI pacemakers. Patients were divided into two groups according to whether or not AF developed during follow-up (mean: 25.7 +/- 2.5 months): group A developed AF and group B did not. The underlying arrhythmias, cardiovascular risk factors, left atrial size, characteristics of P wave were compared between the two groups.

RESULTS

The mean age of the patients was 58.9 +/- 11.4 years and 28 (35%) were male. AF developed in 13 (16.3%) of 80 patients with VVI pacemakers. Sick sinus syndrome (SSS) as an underlying arrhythmia was significantly more frequent in group A than group B (84.6% vs. 44.8%, p < 0.01). P wave width was greater in group A (127.6 +/- 24.8 ms) than in group B (110.7 +/- 17 ms) (p < 0.05). There was, however, no significant difference in cardiovascular risk factors, left atrial size, P wave axis and amplitude between the two groups.

CONCLUSION

These results suggest that sinus node dysfunction and intra-atrial conduction delay may be the risk factors for AF in patients with VVI pacemakers. Further studies are needed to determine how sick sinus syndrome and intra-atrial conduction delay increase the risk for AF in patients with VVI pacemakers.

Protective effect of Oenanthe javanica on the hepatic lipid peroxidation in bromobenzene-treated rats and its bioactive component

To investigate the detoxification of bromobenzene-induced hepatic lipid peroxidation by Oenanthe javanica DC, the hepatic lipid peroxide level and the activities of enzymes responsible for production and removal of epoxide were studied. The level of lipid peroxide elevated by bromobenzene was significantly reduced by the methanol extract (250 mg/kg) and persicarin (5 mg/kg). The methanol extract and persicarin administered daily over 4 weeks before intoxication with bromobenzene did not affect the activities of aminopyrine N-demethylase, aniline hydroxylase, and glutathione S-transferase. Epoxide hydrolase activity was decreased significantly by bromobenzene, which was restored to the control level by pretreatment with persicarin. However, the identical pretreatment with isorhamnetin and hyperoside did not change the enzyme activity or lipid peroxide level. The results suggest that the reduction of bromobenzene-induced hepatic lipid peroxidation by O. javanica under our experimental conditions is effected through enhancing the activity of epoxide hydrolase, an enzyme removing bromobenzene epoxide. In addition, the bioactive component of this plant responsible for the detoxification of bromobenzene, at least in part, is thought to be persicarin.

Tsutsugamushi myocarditis with congestive heart failure and persistent atrial standstill

Acute infectious myocarditis is primarily by viruses and bacteria, but sometimes by rickettsia. Tsutsugamushi disease is a febrile illness caused by Rickettsia tsutsugamushi, and has been prevalent in Korea since 1985. Characteristics of tsutsugamushi disease are fever, rash and eschar. Tsutsugamushi myocarditis is rare. Cardiac involvement may include ST-T changes, PR prolongation, mild mitral regurgitation, and perivascular inflammation with myocardial necrosis. We describe here a 50-year-old woman who complained of fever, orthopnea and chest pain. Work-up of the patient revealed abdominal scar, positive tsutsugamushi antibody, congestive heart failure with severe mitral and tricuspid regurgitation, persistent atrial standstill on electrophysiologic study, junctional rhythm and ST-T changes mimicking anterior myocardial infarction and myocardial inflammation with perivasculitis on endomyocardial biopsy. The patient's condition improved with doxycycline and inotropics. Persistent atrial standstill during was found at the one-year follow-up.

Head-up tilt test with isoproterenol provocation in syncope of unknown origin

OBJECTIVES

Head-up tilt test (HUT) has been reported to be useful in the evaluation of syncope of unknown origin (SUO). However, the sensitivity of HUT with no pharmacologic provocation was relatively low and variable, ranging 32 approximately 70%. Therefore, several protocols of HUT with different degrees and durations of the tilt and modes of provocation were proposed. The purpose of this study was to determine the value of the multi-stage head-up tilt test with isoproterenol provocation (HUT-isp) in the evaluation of SUO and drug efficacy.

METHODS

Sixty-seven patients presenting with SUO and 30 control subjects with no history of syncope underwent the HUT-isp. Blood pressure (BP) was measured every 2 min and whenever the patient complained of any symptom, and cardiac rhythm was continuously monitored. The HUT-isp consisted of 3 stages: first for 20 min with no provocation, second and third stages with infusion of isoproterenol for 10 min each at a rate of 2 micrograms/min and 5 micrograms/min, respectively. A positive HUT-isp was defined when syncope or presyncope was reproduced, accompanied by hypotension (< 80 mmHg) or bradycardia (< 40/min) or both, and positive responses were classified into vasodepressive, cardioinhibitory and mixed type.

RESULTS

The HUT-isp was positive in 56 (83.6%) of 67 patients with SUO and 10 (33.3%) of 30 control subjects. The type of positive responses was vasodepressive in 41 (73.2%), cardioinhibitory in 4 (7.1%) and mixed in 11 (19.6%). The sensitivity of the HUT-isp in diagnosing vasovagal syncope was 83.6%, specificity 66.7% and positive predictive value 84.8%. Positive responses were developed most frequently in the 3rd stage: 76.8% in patients, 70% in controls. The effect of 3 drugs (carteolol, aminophylline and disopyramide) was evaluated in 27 patients with a repeat HUT-isp. Carteolol was effective in 12 (85.7%) of 14 patients, disopyramide in 7 (58. 3%) of 12 and aminophylline in 1 (14.3%) of 7. During the follow-up period of 175 +/- 212 days (26 approximately 623 days), none of the 20 patients with a negative repeat HUT-isp developed a recurrent syncope.

CONCLUSION

The HUT-isp is thought safe and useful to evaluate syncope of unknown origin and to guide effective drug therapy.

Diterpenoid alkaloids from Delphinium davisii

Three new hetisane-type diterpenoid alkaloids, davisinol (6), 18-benzoyldavisinol (7), and Davisin (9) have been isolated from Delphinium davisii Munz. and their structures established by detailed spectroscopic studies. Accurate 1H- and 13C-NMR assignments have been made for kobusine (8), a related hetisane-type alkaloid, and karakoline (5), a norditerpenoid alkaloid. The known norditerpenoid alkaloids 14-acetylperegrine (4), 6-deacetylperegrine (3), and karakoline (5) and the diterpenoid alkaloids hetisine and hetisinone were also isolated.

Acute hemodynamic improvement by thermal vasodilation in congestive heart failure

BACKGROUND

A warm-water bath (WWB) or sauna bath (SB) has generally been considered inappropriate for patients with severe congestive heart failure (CHF). However, a comprehensive investigation of the hemodynamic effects of thermal vasodilation in CHF has not been previously undertaken.

METHODS AND RESULTS

To investigate the acute hemodynamic effects of thermal vasodilation in CHF, we studied 34 patients with chronic CHF (mean age, 58 +/- 14 years). Clinical stages were New York Heart Association functional class II in 2, III in 19, and IV in 13 patients. Mean ejection fraction was 25 +/- 9%. After a Swan-Ganz catheter was inserted via the right jugular vein, the patient had a WWB for 10 minutes at 41 degrees C or an SB for 15 minutes at 60 degrees C. Blood pressure, ECG, echo-Doppler, expiration gas, and intracardiac pressures were recorded before, during, and 30 minutes after each bath. Oxygen consumption increased mildly, pulmonary arterial blood temperature increased by 1.2 degrees C, and heart rate increased by 20 to 25 beats per minute on average at the end of WWB or SB. Systolic blood pressure showed no significant change. Diastolic blood pressure decreased significantly during SB (P < .01). Cardiac and stroke indexes increased and systemic vascular resistances decreased significantly during and after WWB and SB (P < .01). Mean pulmonary artery, mean pulmonary capillary wedge, and mean right atrial pressures increased significantly during WWB (P < .05) but decreased significantly during SB (P < .05). These pressures decreased significantly from the control level after each bath (P < .01). Mitral regurgitation associated with CHF decreased during and 30 minutes after each bath. Cardiac dimensions decreased and left ventricular ejection fraction increased significantly after WWB and SB. In an additional study, plasma norepinephrine increased significantly during SB in healthy control subjects and in patients with CHF and returned to control levels by 30 minutes after SB.

CONCLUSIONS

Hemodynamics improve after WWB or SB in patients with chronic CHF. This is attributable to the reduction in cardiac preload and afterload. Thus, thermal vasodilation can be applied with little risk if appropriately performed and may provide a new nonpharmacological therapy for CHF.

Two new norditerpenoid alkaloids from Delphinium elatum var. "black night"

Two new norditerpenoid alkaloids, blacknine [1] and blacknidine [2], have been isolated from the whole plants of Delphinium elatum var. "black night" along with six known alkaloids. The structures of the new alkaloids 1 and 2 were derived from their spectroscopic data (1H, 13C, DEPT, COSY, HETCOR, and selective INEPT nmr experiments). The phytochemistry of this plant variety has not been examined previously.

Adaptation of Aspergillus niger to several antifungal agents

Adaptation of Aspergillus niger to short-term stress induced by three antifungal agents [amphotericin B (AMPH), miconazole (MCZ), and ketoconazole (KCZ)] was observed and evaluated quantitatively using individual hyphae. Spores were inoculated onto a poly-L-lysine-coated glass plate making up the base of a culture vessel. Potato dextrose broth (PDB) was added and the vessel incubated for 24 h at 28 degrees C. The growth rate of an arbitrarily selected test hypha was measured automatically. Exposure to AMPH (0.075 micrograms ml-1) stopped the growth of the hypha. After washing with PDB, the same concentration of AMPH was applied again. The growth of the test hypha was not inhibited. This phenomenon was defined as adaptation to the short-term stress of AMPH. Similarly, adaptation was observed with MCZ (0.01 microgram ml-1) and KCZ (0.5 microgram ml-1). The time required for the test hypha to restart growth after washing with PDB depended upon the concentration of MCZ or KCZ, but not upon the concentration of AMPH.

[Effects of hot water bath or sauna on patients with congestive heart failure: acute hemodynamic improvement by thermal vasodilation]

The acute hemodynamic effects of thermal vasodilation caused by exposure to hot water bath or sauna in chronic congestive heart failure were investigated in 32 patients (mean age 57 +/- 15 years old) with dilated cardiomyopathy (25 idiopathic and 7 ischemic). The clinical symptoms were New York Heart Association Class II in 2 patients, III in 17 and IV in 13, and the mean ejection fraction was 25 +/- 9% (9-44%). Exposure to hot water bath was for 10 minutes at 41 degrees C in a semi-sitting position, and to sauna for 15 minutes at 60 degrees C in a supine position using a special far infrared ray sauna chamber. Blood pressure, electrocardiogram, two-dimensional and Doppler echocardiograms, expiration gas, and intracardiac pressure tracings were recorded before (control), during, and 30 minutes after hot water bath or sauna. 1. The increase in oxygen consumption was only 0.3 Mets during hot water bath or sauna, and returned to the control level 30 minutes later. 2. The deep temperature in the main pulmonary artery increased by 1.0-1.2 degrees C on average at the end of hot water bath or sauna. 3. Heart rate increased significantly (p < 0.01) by 20-25/min during bathing and still increased 30 min later. 4. Systolic blood pressure did not change significantly during and after hot water bath or sauna, while, diastolic blood pressure decreased significantly during (p < 0.05) and after sauna (p < 0.01), and after hot water bath (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Slowed receptor trafficking in mutant CHO lines of the End1 and End2 complementation groups

A mutant Chinese hamster ovary cell line with nonconditional kinetic defects in receptor internalization and recycling was isolated, based on selection for resistance to a transferrin-diphtheria toxin conjugate and screening for aberrant receptor trafficking. The 12-4 cell line internalizes transferrin at approximately 75% of the parental rate and recycles transferrin back to the cell surface at approximately 55% of the parental rate. Internalization of low density lipoprotein is also reduced to approximately 70% of the parental cell rate, demonstrating that the mutant phenotype affects the trafficking of multiple receptors. Characterization of somatic cell hybrids indicated that the 12-4 phenotype is recessive, and complementation analysis determined that the 12-4 cell line is a member of the End2 complementation group. End2 mutants have previously been described as defective in endosomal acidification but have not been known to be defective in receptor trafficking. We have found similar defects in another End2 mutant cell line, suggesting that slowed receptor trafficking is characteristic of End2 mutants. Interestingly, transferrin receptor recycling and internalization are also slowed in another complementation group of mutants, End1, that is also defective in endosomal acidification. This study demonstrates altered receptor trafficking in End1 and End2 cell lines, a novel aspect of the mutant phenotypes. These findings provide evidence, based on a cellular genetic approach, that proper endosome acidification is necessary for maintenance of normal receptor recycling.

An efficient computer model of three-dimensional speckle patterns in dynamically focused annular array

This paper describes an efficient computer method for generating three-dimensional (3-D) ultrasonic speckle patterns for sector scans of an annular array with dynamic focusing in both transmit and receive. Assuming random scatterers in an attenuating medium, the system synthesizes the waveform for each scan line using echo data received at all annular elements of the transducer when short pulses are transmitted by one annulus after another. The amount of echo data needed to synthesize one waveform is tremendously reduced by reducing the 3-D distributions of scatterers to line distributions and by representing scatterers on a small line segment by a single equivalent scatterer taking into account the two-way travel time differences. Furthermore, by a judicious 3-D arrangement of the scatterer lines and scan lines, it is possible to synthesize the waveform for a new scan line with negligible computation overhead. The waveforms of the scan lines are detected to obtain a B-mode image or speckle patterns. The patterns obtained on several differently-oriented image planes showed a good statistical agreement with experimentally obtained patterns.

Effect of calcification and formalin fixation on in vitro distensibility of human femoral arteries

To determine the effect of calcification on the distensibility of human arteries, we measured changes in lumen cross-sectional area as a function of pressure in excised segments of calcified and noncalcified human femoral arteries with the use of intravascular ultrasound. Cross-sectional area at zero pressure was greater in calcified artery segments (22.1 +/- 4.4 mm2) compared with noncalcified arteries (18.9 +/- 2.4 mm2). Calcified arteries were significantly less distensible than noncalcified arteries (2.5-fold). To assess the validity of mechanical tests of fixed arteries, pressure-area relations were also obtained after formalin fixation: mean unstressed cross-sectional area decreased significantly in noncalcified arteries (24%) but did not change significantly in calcified arteries. Formalin fixation decreased distensibility significantly (68%) in noncalcified arteries but not in calcified arteries. These results indicate that decreased lumen size and increased rigidity are induced by formalin fixation in noncalcified arteries but not in calcified arteries, and that this is attributable to the lower distensibility of calcified arteries before fixation. Because histologic examination is commonly used to evaluate severity of lumen narrowing in studies of atherosclerosis, this differential effect of formalin fixation may cause calcified arteries to appear less severely obstructed than noncalcified arteries.

Early outcome of PTCA in totally occluded coronary arteries

BACKGROUND

Since percutaneous transluminal coronary angioplasty (PTCA) was first introduced in 1977 by Gruentzig as a treatment for proximal short-segmental, non-calcified, concentric isolated coronary stenosis, it has been used with increasing frequency in patients of symptomatic coronary artery disease with broader indications, including patients with multi-vessel disease, unstable angina, acute myocardial infarction and totally occluded coronary arteries. Among these, total coronary occlusion constitutes a subdivision with specific features that require separate evaluation. The purpose of this study was to determine the initial results of PTCA for total coronary occlusion.

METHODS

Thirty-five patients with manifested ischemic heart disease with totally occluded coronary arteries, documented by coronary angiography, underwent recanalization procedure by PTCA between Jan. 1990 and Oct. 1991.

RESULTS

Thirty-five patients were comprised of 20 acute myocardial infarction (MI), 7 old MI and 8 unstable angina. Eighteen (50.1%) patients had one major atherosclerosis risk factor and 10 (29.4%) had two or more. PTCA for total coronary artery occlusion was attempted in the left anterior descending artery (LAD) in 16 patients, right coronary artery (RCA) in 11, left circumflex artery (LCx) in 2 and protected left main in one. PTCA was successful in 23 patients (66%): LAD in 11/18 (61%) and RCA 11/14 (79%), showing significantly higher success rate with RCA than LAD (p < 0.05). Primary success rate of PTCA in accordance with the duration of the total occlusion estimated on the basis of clinical and angiographic data was 71% (15/21) when less than two weeks, 63% (5/8) when between 2 to 12 weeks, and 50% (3/6) longer than 12 weeks. Mean duration of the total occlusion in successful PTCA was 1.4 months (range; 10 days-5 months) and, 1.7 months (range; 3 weeks-3 years) in failed PTCA. Diameter stenosis of the lesions was significantly decreased from 100% to 19.7% after successful PTCA. There was no death but 2 patients were complicated with coronary artery embolization occluding major distal branches.

CONCLUSION

The study suggested that PTCA of total coronary artery occlusion can be performed safely and effectively in selected cases and might be more successful in the lesion with shorter duration of occlusion.

In vitro validation of three-dimensional intravascular ultrasound for the evaluation of arterial injury after balloon angioplasty

OBJECTIVES

The hypothesis of this study was that three-dimensional ultrasound imaging would facilitate the evaluation of arterial dissection after balloon angioplasty.

BACKGROUND

The presence and extent of arterial dissection occurring at the time of balloon angioplasty may be important predictors of abrupt vessel closure or late restenosis.

METHODS

Forty-one human arterial segments obtained after death were imaged in an in vitro system at physiologic pressure (80 to 100 mm Hg) before and after balloon angioplasty. Images were acquired with a 20- to 30-MHz mechanical intravascular ultrasound imaging system (Cardiovascular Imaging Systems) with a constant pullback technique (1 mm/s). Standard 0.5-in. (1.27-cm) video tapes were used for data storage and later playback for analog to digital conversion. Digitized data were reconstructed to three-dimensional images with use of voxel space modeling. The vessels were opened longitudinally and subjected to pathologic examination, photographed and classified histologically as normal, fibrous or calcified. Dissection was defined as a disruption and separation of components of the arterial wall. The length and depth of arterial dissection were evaluated grossly and microscopically.

RESULTS

Of the 41 arteries studied, 36 (88%) exhibited dissection on pathologic examination after balloon angioplasty. Three-dimensional reconstruction of intravascular ultrasound images identified dissection in 11 (92%) of 12 normal, 8 (100%) of 8 fibrous and 11 (69%) of 16 calcified arteries. Excellent agreement between ultrasound and pathologic findings was achieved in the evaluation of length and depth of dissection for histologically normal and fibrous arteries (kappa = 0.72 to 1.0). When the vessels were severely calcified, the agreement was not as good (kappa = 0.27 to 0.56), particularly in detection of small, non-raised intimal flaps.

CONCLUSIONS

This histopathologic validation study suggests that three-dimensional intravascular ultrasound imaging facilitates the evaluation of both quantitative and morphologic features of arterial dissection induced by balloon angioplasty. The advantage of three-dimensional intravascular ultrasound is its ability to assess the length and morphology of arterial injury over an entire vessel segment.

Nucleotide sequence of the extracellular alpha-amylase gene in the yeast Schwanniomyces occidentalis ATCC 26077

The Schwanniomyces occidentalis (formerly castellii) ATCC 26077 (CBS 2863) alpha-amylase (AMY 26077) gene was cloned in Saccharomyces cerevisiae and sequenced. An open-reading frame encoding the AMY consists of 1536 base pairs and contains 512 amino-acid residues, which is almost the same in size as the AMY of Sch. occidentalis ATCC 26076 and CCRC 21164. The amino-acid sequence of AMY 26077 differed from that of ATCC 26076 alpha-amylase (AMY 26076) at two residues and from that of CCRC 21164 alpha-amylase (AMY 21164) at three residues. Comparison of the AMY 26077 gene with its homologues from two other strains (Sch. alluvius CBS 1153 and Sch. persoonii CBS 2169) using several restriction enzymes revealed that the AMY 26077 was very similar to AMY CBS 1153 but different from that of CBS 2169.

Cholinesterase activity in vestibular organs of young and old mice

The activities of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) were studied by histochemical methods in the semicircular canal end organs, the utricle and the saccule of young and old mice. AChE was located on the plasma membrane of efferent nerve terminals beneath vestibular hair cells, and along the basement membrane. In the ampulla, stained efferent terminals were more prevalent on the slopes of the crista than in the central region. In all organs examined, there were no discernible differences in AChE activity between young and old mice. BChE activity was observed in the epithelial light cells and supporting cells of the saccule, utricle, and ampulla. Its distribution was similar in both young and old mice in the ampulla, but decreased significantly with age in the utricle. Preliminary data suggest that BChE activity is also weak in old saccular supporting cells. Unlike the utricle, old saccular light cells retained intense BChE activity.

Histopathologic validation of angioscopy and intravascular ultrasound

BACKGROUND

To establish a histopathologic basis for angioscopic and ultrasound image interpretation we studied 70 postmortem human arterial segments in vitro.

METHODS AND RESULTS

We used 7- to 9-French fiber-optic angioscopes and 20- to 30-MHz intravascular ultrasound imaging catheters. Three observers assigned an angioscopic and ultrasound image classification to each vessel segment. The image and histological classification categories were then compared. The sensitivity, specificity, and accuracy of both methods separately or in combination for normal vessels were each greater than or equal to 95%. The predictive value was better for angioscopy than for ultrasound due to incorrect ultrasound interpretations of normal anatomy in the presence of thrombus. For stable atheroma the sensitivity, specificity, and accuracy of the individual methods were each greater than 90%. However, both angioscopy and ultrasound had classification errors in that disrupted atheroma was identified and classified as stable atheroma. Consequently, the predictive value was 74% for angioscopy and 78% for ultrasound. For disrupted atheroma the sensitivities for angioscopy and ultrasound were only moderate (73% and 81%, respectively), whereas the specificity, accuracy, and predictive value were each high (greater than 90%). For thrombus detection, the specificity, accuracy, and predictive value were high (greater than 93%) for each method. The sensitivity of angioscopy was 100%. However, sensitivity was lower for ultrasound (57%) due to false-negative interpretation of laminar clots in normal vessels and an inability to distinguish disrupted or stable atheroma from intraluminal thrombus.

CONCLUSIONS

Contingency analyses showed that each imaging method alone or combined had significant agreement with the results obtained from histology (p less than 0.001). When assessing all cases in which angioscopy and ultrasound were concordant, there was a 92% agreement with the histological classification.

Survey of the presence of the Fusarium mycotoxins nivalenol, deoxynivalenol and T-2 toxin in Korean cereals of the 1989 harvest

Twenty eight samples of rice, barley, millet, corn and Indian millet harvested in Korea in 1989 were subjected to assay for contamination of nivalenol (NIV), deoxynivalenol (DON) and T-2 toxin by using gas chromatography and gas chromatography-mass spectrometry. Seven samples were found to be positive for NIV and DON in the ranges of 189-624 micrograms/kg and 168-506 micrograms/kg, respectively. Of the contaminated samples, three samples, one barley, one Indian millet and one corn sample were contaminated simultaneously with both NIV and DON. T-2 toxin was not detected in any samples.

Dietary restriction slows the abnormally rapid loss of spiral ganglion neurons in C57BL/6 mice

Dietary restriction as a means extending the life span and exploring the aging process has interested researchers for over 50 years. We wanted to determine whether dietary restriction would alter the unusually rapid aging of the auditory ganglion in the C57BL/6NNia mouse. Quantitative methods were used to estimate the number of spiral ganglion neurons in the cochleas of 18 month-old dietary restricted and ad libitum-fed C57BL/6NNia mice. The number of spiral ganglion neurons in dietary restricted mice was significantly higher than those on an ad libitum diet. This is the first study to quantitatively demonstrate that severe neuron loss in the auditory ganglion of a mouse suffering inherited, prepubertal deafness can be slowed by caloric restriction.

Comparison of demyelination and neural degeneration in spiral and Scarpa's ganglia of C57BL/6 mice

Spiral and Scarpa's (vestibular) ganglia of female C57BL/6 mice, ranging in age from 1.5 to 32 months, were examined by light and electron microscopy. The spiral ganglia of C57BL/6 mice undergo sweeping neuronal losses. Based on cytological characteristics that repeat themselves in both young and old mice, we divided perikaryal demyelination and degeneration of spiral ganglia into four arbitary stages: 1) incipient demyelination, myelin sheaths begin to loosen and unravel; 2) contact, the partially demyelinated perikarya abut as the extracellular matrix disappear; 3) clumping, clusters of naked perikarya clump together, cytoplasmic processes surround the exterior of the clump; and 4) resorption, the clumps gradually disintegrate, leaving at completion large, fluid-filled spaces and few cellular remnants. In Scarpa's ganglia, a small number of neurons demyelinate and clump, but none degenerate or undergo resorption.

Suprasternal M-mode echocardiography of the right pulmonary artery as a model for investigation of pulmonary hemodynamics in essential hypertension

The right pulmonary artery (RPA) dimensions of 85 asymptomatic mild or moderate hypertension (HT) patients, divided into 6 subgroups according to the left ventricular (LV) mass index (125g/m2 BSA) left atrial (LA) dimension index (2.2cm/m2 BSA), and 40 normal subjects were studied utilizing suprasternal M-mode echocardiography in order to examine the consistency of the elevated PA pressure in essential HT and to understand its pathogenesis. The RPA dimension at late diastole, at the end of the right ventricular isovolumic contraction, and at systole in the subgroup of HT without LV hypertrophy and LA enlargement was significantly increased compared with those of the normal group (18.4 +/- 2.8 vs 16.2 +/- 2.3mm, 19.6 +/- 3.0 vs 17.2 +/- 1.3mm, 22.5 +/- 2.5 vs 20.8 +/- 1.9mm, p less than 0.05, respectively) and varied in close correlation with systolic and diastolic BP and the dimension of the aorta. The dimensions in the other 5 subgroups were the same and were not further affected by the LV mass and LA dimension. The above results suggest that elevated systemic BP per se is associated with the dilation of the RPA supposedly caused by increased PA resistance, besides the backward effect of the increased LV and/or LA pressure which may affect the increase of PA pressure.