Endoscopic mucosectomy for early cancer using a pre-looped plastic cap.
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Biomedical subjects
Publications and source records attributed to M Endo.
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To elucidate the characteristic myocytic changes in chronic ischemic myocardium, an electronmicroscopic (EM) study was carried out in surgically excised postmyocardial infarction left ventricular aneurysm (LVAN) (n = 15) using semiquantitative (in all 15 cases) and quantitative assessment methods (in 10 cases). The control group, representing normal ultrastructure, included left ventricular endomyocardial biopsy specimens of sick sinus syndrome (SSS) (n = 3), Wolff-Parkinson-White (WPW) Syndrome (n = 1), and intraoperative left ventricular endomyocardial biopsy in mitral stenosis (MS) (n = 3). Myocardial condition was assessed at the ultrastructural level according to the severity of morphologic changes, first semiquantitatively, thereafter with the use of the Image Processor-Analyzer LUZEX III for morphometric analysis. The most marked EM findings were mitochondrial regressive changes, glycogen accumulation, nuclear deformities, increased rough-surfaced endoplasmic reticulum at the perinuclear portion, lysis of myofibrils, and myofibrillar degeneration. The quantitative analysis revealed significant (p < 0.05) increase of glycogen deposition, only at the perinuclear portion in the LVAN group. The myofibril to mitochondria ratio at the intercalated disc (ID) portion of the cardiac myocytes significantly increased (p < 0.01) in the LVAN group as compared with the normal control group. Light microscopically evaluated quantitative analysis, using toluidine-blue stained semithin sections which underwent EM observation, showed that the fractional area of interstitial fibrous tissue was significantly increased in the LVAN group compared to the normal controls (p < 0.01). These results signify that in chronic ischemic myocardium, decreased consumption of glycogen in oxidative phosphorylation occurs in the surviving myocytes, and that hypertrophy of the myocytes appears. The results of this study may lead to the proper ultrastructural interpretation of biopsied human myocardium, regardless of etiology.
As potential antineoplastic agents, we have synthesized 4'-thioFAC and 4'-thiocytarazid by developing an alternative synthetic method. 4'-ThioFAC showed potent antineoplastic activities in vivo as well as in vitro.
The authors developed a new waterproof-packed infusion device for easy and sterile in-storage hypothermic perfusion during organ transportation for heart and lung transplantation. They examined the accessibility and efficacy of this infusion device for portable heart and lung preservation in canine transplant models. Sixteen heart and bilateral lung blocks were preserved by an in-storage hypothermic perfusion technique using the infusion device with University of Wisconsin solution. Of 16 dog recipients, 5 underwent orthotopic heart transplantation with cardiopulmonary bypass, and 5 dogs received left lung transplantation; the remaining heart and lung blocks were intrathoracically transplanted into 6 dogs. Functional status and histology of 11 heart and 11 lung allografts were evaluated by post-transplant course, hemodynamic parameters, arterial blood gas measurements, microscopic examination, and so on. Eleven transplanted hearts showed good cardiac performance and maintained systemic circulation after weaning from cardiopulmonary bypass. Eleven transplanted lungs had excellent respiratory function, and all five dogs with left lung transplantation survived for 5-46 days (mean: 18.8 days). These results suggest that in-storage hypothermic perfusion with this waterproof-packed infusion device can be a useful technique for long-term organ preservation in heart and lung transplantation.
The authors have examined the possibility of usage of an internal thoracic artery (ITA) homograft as a new small caliber vascular substitute. Left subclavian artery to left atrial appendage shunts with fresh ITA homografts (n = 6) or ITA autografts (n = 5) were made by modified techniques of coronary artery bypass grafting in mongrel dogs (body weight, 11-16.5 kg). All recipient dogs had no anticoagulant therapy or immunosuppression. Inner diameter of the grafts was between 1.4 and 2.0 mm. Blood flow in ITA grafts was measured by electromagnetic flow meter. The graft flow was 6-14 ml/min before harvest and 67-220 ml/min just after implantation, and there was no significant difference between groups. Flow in the ITA homografts decreased significantly compared with ITA autografts 1 month after operation, but five of six ITA homografts were patent. Histopathology of the grafts showed vascular rejection in the homograft group. These results suggest that an ITA homograft with postoperative immunosuppression might be a new small caliber vascular substitute for coronary artery bypass grafting in ischemic heart disease and the systemic-pulmonary shunt operation in congenital heart diseases.
Activated leukocytes and oxygen free radicals have been implicated in the pathogenesis of heart and lung injury after reperfusion and during cardiopulmonary bypass. This study was designed to determine whether leukocyte depletion prevents injury to the heart and lung during cardiopulmonary bypass. Twenty-eight open heart surgeries were performed in this study. In Group F, leukocyte depletion was performed with an LG-6 arterial line filter after aortic declamp (n = 14). Leukocyte depletion was not performed during cardiopulmonary bypass in Group C (n = 14). Thereafter, cardiac and lung function were assessed in the 24 hr after reperfusion. The total catecholamine dose used for 24 hr after reperfusion (r) was 61.9 +/- 13.4 in Group C and 43.9 +/- 19.2 in Group F (p < 0.05). CK-MB at 3 and 6 hr after reperfusion was 65.9 +/- 13.5 and 64.8 +/- 15.8 in Group C and 45 +/- 11.8 and 38 +/- 10.8 in Group F, respectively (p < 0.05). The pulmonary index after reperfusion at 3 and 6 hr was 1.7 +/- 0.5 and 1.3 +/- 0.4 in Group C and 0.7 +/- 0.3 and 0.6 +/- 0.4 in Group F, respectively (p < 0.05). There was significantly better preserved lung function in Group F. In conclusion, leukocyte depletion was significantly effective in preserving heart and lung function during cardiopulmonary bypass.
A safe and reliable method of weaning from a left ventricular assist system (LVAS) is necessary for successful circulatory support in patients with marginal heart failure. The purpose of this study is to assess the effect of additional intraaortic balloon (IAB) support during weaning from an LVAS by means of the LV pressure-volume relationship. A pneumatic LVAS with a sac-type blood pump was implanted in six adult mongrel dogs weighing 14 to 20 kg. All dogs had a drainage cannula placed in the left atrium and an outflow conduit in the ascending aorta. Hemodynamic parameters, pulmonary arterial flow, and pump output were monitored. An IAB was inserted through the groin. A conductance catheter and microtip manometer were inserted into the LV cavity. As a combination driving mode, LVAS ejection in the early diastolic phase and IAB inflation in the late diastolic phase were applied. After evaluation of baseline LV function, the pressure-volume relationship was repeatedly measured during change of driving modes as isolated LVAS, LVAS + IAB (1:1), LVAS + IAB (2:1), and isolated IAB supports. Finally, LV failure was introduced by stepwise ligation of left coronary arteries, and the LV pressure-volume relationship was measured in each driving mode. Under normal conditions, the pressure-volume loop showed no significant change among the four driving modes. In contrast, the LV pressure-volume relationship significantly improved according to the degree of additional IAB support on LVAS assistance under the condition of LV failure. These results suggest that additional IAB support might improve LV energy during weaning from an LVAS.
To facilitate the handling of cardiopulmonary bypass (CPB) and simplify the circuit, the authors have developed a new membrane oxygenator with a hemofiltration function. The hollow fiber units for gas exchange and hemofiltration were combined in concentric circles in a cylindrical housing. The total priming volume was 190 ml. Because the authors adopted a silicon coated hollow fiber membrane for gas exchange, this oxygenator was completely resistant to serum leakage, even after treatment to make the device hydrophilic. Both units possess a blood-outside perfusion system. Filtered fluid was collected easily through a stopcock mechanism. The oxygen transfer rate was 312 ml/min at a blood flow rate of 6 L/min, and the ultrafiltration rate was 3.5 L/hr at a blood flow rate of 4 L/min with a 25% hematocrit and 200 mmHg transmembrane pressure in an in vitro study. The pressure drop was 62 mmHg at a blood flow rate of 4 L/min. The authors found no adverse effects in an in vivo study using a mongrel dog. In conclusion, this durable, combined device could achieve excellent and simplified hemoconcentration through having all the blood in the unit flow through the hemofiltration portion, and was useful not only in cardiopulmonary bypass during open heart surgery, but also in extracorporeal membrane oxygenation.
Angiogenesis by basic fibroblast growth factor (bFGF) is important for endothelialization in vascular prostheses and is significant from shortly after implantation. Canine adipose tissue was resected, minced into fragments, and suspended. This mixture was sieved through the wall of a fabric vascular prosthesis. Tissue-fragmented grafts (TF-grafts, 6 mm internal diameter, 6 cm long) were implanted into the abdominal aortae of four dogs, and four preclotted grafts were used as control subjects. Grafts were removed at 1-7 days after implantation. Removed grafts were evaluated microscopically, immunohistologically, and by scanning electron microscope. At day 1, a thrombus layer was on the TF-graft lumen. At day 3, cell proliferation and migration were observed. At day 5, endothelial-like cells were extending onto the luminal thrombus. Cell proliferation around the fragments was active, and those cells were bFGF positive. In the control subjects, at day 7, the perigraft tissue was bFGF positive, whereas no endothelialization on the lumen or no capillary infiltration into the graft wall was observed. Furthermore, bFGF was negative in the sites of thrombus and infection. These results demonstrate that endogenous bFGF is important for endothelialization due to angiogenesis in fabric vascular prostheses, whereas thrombus and infection might have a negative effect.
To clarify determinants of clinical results of circulatory support for ventricular failure after cardiotomy, we examined 53 patients (33 men and 20 women) who underwent circulatory support for post operative heart failure from 1984 to October 1995. Their ages ranged from 22 to 74 years (mean, 51 years). In 53 patients, 32 had valvular, 19 had ischemic, and 2 had congenital heart disease. After operation, 21 patients underwent venoarterial bypass, 20 underwent biventricular bypass, and 8 underwent left ventricular bypass. The remaining 4 patients received a pulsatile left ventricular assist device. Weaning and discharge rates of the patients by type of support were 52.4% and 28.6% with venoarterial bypass, 75.0% and 55.0% with biventricular bypass, 87.5% and 37.5% with left ventricular bypass, and 75.0% and 50.0% with left ventricular assist device, respectively. The results of this series (67.9% weaning rate and 41.5% discharge rate) were acceptable. Peri-operative variables before and during circulatory support were analyzed multivariately by logistic regression analysis. Selected independent determinants (odds ratio) of significant difference (p < .05) were type of support (7.547) for non weaning and pre support cardiogenic shock (17.246), and type of support (8.780) and support duration (1.487) for mortality. These results suggest that early application before profound shock and appropriate selection of type of support might be key factors in successful circulatory support for ventricular failure occurring after cardiotomy.
Healing characteristics of small-caliber vascular prostheses used in small children have rarely been observed because removing specimens are troublesome. Modified Blalock Taussig shunt procedures were performed using small caliber expanded polytetrafluoroethylene (ePTFE) vascular grafts and fabric grafts in 13 patients with congenital heart disease. At the time of total corrective procedures, a piece of 10 ePTFE grafts in 10 patients and six fabric grafts in four patients were removed from the distal pulmonary anastomosis, and evaluated. The implantation duration was from 11 months to 5 years and 7 months (mean, 2 years and 6 months). At removal, average patient age was 4 years and all grafts were patent. Microscopically, the wall of three ePTFE grafts were calcified, and macrophages were immunohistologically observed in the graft wall. Thrombus formation, intimal hyperplasia, and pannus detachment was common. In the fabric grafts, many capillaries infiltrated the interstices and often reached the lumen from the perigraft side. These results suggested that in cyanotic small children, angiogenesis in and around fabric grafts was active and calcification was accelerated in ePTFE grafts. Complete endothelialization throughout the length, caused by angiogenesis, might be possible in small children when highly porous fabric vascular prostheses are used.
OBJECTIVE: Cardiac PET imaging offers the potential capability for the noninvasive measurement of arterial input function. This capability is somewhat limited, however, because of partial volume and spillover effects. The purpose of this study was to validate arterial tracer concentration measurements using PET images by assigning a region of interest (ROI) to the left ventricle, left atrium (LA), and ascending aorta. MATERIALS AND METHODS: We selected [11C]CO and [13N]ammonia as tracers, because the activity of [11C]CO is primarily in the blood pool and that of [13N]ammonia primarily in myocardial tissue. Six [11C]CO and 11 [13N]ammonia PET scans were obtained in 17 subjects. Arterial tracer concentrations determined by PET were compared with those measured by well counting of arterial blood sampling obtained at the midpoint of each image acquisition. RESULTS: Arterial tracer concentrations as determined by LA-PET imaging correlated closely with those measured by blood sampling (r = 0.996, slope = 1.00 for [11C]CO; r = 0.841, slope = 0.974 for [13N]ammonia). Partial volume and spillover effects were minimized by assigning an ROI to the LA. CONCLUSION: Arterial tracer concentrations can be measured noninvasively with cardiac PET.
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To investigate the relationship between biliary mucin and ductular stone formation, mucin was isolated from hepatic bile using gel filtration on Sepharose CL-4B. The bile was obtained from 14 patients with stones in various sites of the biliary tract. The hexose content in the excluded fraction was significantly higher in patients with intrahepatic ductular stones (68.7 +/- 20.5 micrograms/mL; mean +/- s.d.) than in those with gall-bladder stones or extrahepatic ductular stones (23.8 +/- 8.1 micrograms/mL, 33.3 +/- 9.5 micrograms/mL; P less than 0.05), suggesting a higher concentration of mucin in the bile of patients with intrahepatic ductular stones. Ion-exchange chromatography on DEAE-Sephacel showed that most mucin from each material was negatively charged and electrophoretic studies indicated that it was composed mainly of high molecular weight (greater than 10(6)), sulfated glycoprotein. These results suggested that the mucin content of hepatic bile might have an important relation to the development of intrahepatic ductular stones.
In experiments using pregnant rats, the following results were noted: (a) Of the amygdaloid kindled rats, the generalized seizure triggering threshold of the pregnant group was significantly higher than that of the nonpregnant group. (b) Of the rats taking oral phenobarbital, 4 mg/kg once a day, there was no significant difference of serum levels between the pregnant group and the nonpregnant group. (c) Of the amygdaloid kindled rats taking oral phenobarbital, 4 mg/kg once a day, the generalized seizure triggering threshold of the pregnant group was significantly higher than that of the nonpregnant group. It may be suggested that, when the drug dose remains the same, the rise in threshold by gestational physiological changes antagonizes the fall in threshold by decreased serum levels of anticonvulsants because of increasing distribution volume due to increasing body weight during pregnancy.
We describe a possible route for large-scale synthesis of single wall carbon nanotubes (SWNTs) by a combination of the substrate and floating methods. The template prohibits metal particle aggregation, resulting in high-purity SWNT growth, and the three-dimensional floating seeded state of the template induces improved yields of SWNTs in a semi-continuous system. The SWNTs obtained by this method exhibit large variations of texture (isolated tubes and bundles) and a wide range of diameters (0.4-4 nm).
Thirty-five infants who had tracheoesophageal fistula, esophageal stenosis, anal atresia, or Hirschsprung's disease were managed with various types of parenteral solution after their radical operations. The infants were divided into 6 groups and given 1) the usual low calorie infusion consisting of 5% glucose, water, and electrolytes, 2) high calorie formula consisting of 21 g/kg/day glucose, and 4 g/kg/day synthesized crystalline L-amino acids, 3) solutions without phosphate, 4) solutions of Cal/N ratio 200 providing 4 g/kg/day amino acids, 5) solutions of Cal/N ratio 400 providing 2 g/kg/day amino acids, and 6) a regimen containing fat emulsion. Nitrogen (N) and phosphorus (P) balances, blood urea nitrogen (BUN), blood glucose, plasma phosphate, immunoreactive insulin (IRI), and non-esterified fatty acid (NEFA) values were investigated. Parenteral solutions, providing 100 Cal/kg/day of Cal/N ratio 200, yielded sufficient positive N balance (120 mg/kg/day average). High calorie solutions without phosphate caused marked hypophosphatemia (0.3 mEq/1) with undetectable P in 24-hr urine. P balance correlated with N balance. Solutions of Cal/N 400 induced a lower BUN level, although there was a cumulative negative N balance. Solutions of Cal/N 200 induced higher levels of IRI and lower glucose than those of Cal/N 400. Increased IRI response and remarkedly decreased NEFA levels were seen in the group administered solutions without fat. Solutions with fat emulsion suppressed IRI response and improved the level of plasma NEFA.