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Biomedical subjects

T Shoji

Publications and source records attributed to T Shoji.

At least 307 records · Page 17Linked to original sources
PubMed1989

Quantification of area and percentage of infarcted myocardium by single photon emission computed tomography with thallium-201: a comparison with serial serum CK-MB measurements.

In order to quantify the size of the infarcted myocardium, two kinds of data processing techniques were applied to single photon emission computed tomography (SPECT) with thallium-201 and its clinical reliability was evaluated by comparing it with the infarct sizing procedure with the serial serum creatine kinase-MB measurements in 14 patients with acute myocardial infarction. After maximum-count circumferential profile analysis, short axis images were reformatted into an unfolded surface map and a bull's eye view map. The SPECT-determined infarct size was defined as the area or the percentage of hypoperfused myocardium of which the profile count was less than the mean minus 2SD derived from 8 normal subjects. The infarct area was calculated from the number of pixels with an abnormal count and expressed in an unfolded surface map. The percentage was calculated from the number of abnormal profile points and displayed in a bull's eye view map. A high linear correlation was observed between the enzymatically determined infarct size and the infarct area or the percentage (r = .947, r = .872, respectively), despite underestimations in 2 patients with accompanying right ventricular infarction and overestimations in 2 patients with prior anterior infarction. Moreover, a close negative correlation was found between the left ventricular ejection fraction and the infarct area or the percentage (r = .836, r = .821, respectively). Thus, the semiautomatic techniques for processing thallium-201 SPECT images might contribute to the quantitative estimation and display of infarcted myocardium and have high clinical reliability.

Adult↗
PubMed1989

Relationship between sarcolemmal damage and appearance of amorphous matrix densities in mitochondria following occlusion of coronary artery in rats.

The relationship between the progression of sarcolemmal damage and the appearance of amorphous matrix densities (AMDs) within myocardial mitochondria in the early phase of ischemia was studied in coronary-ligated rats by means of electron microscopy. The animals were divided into six groups according to the duration of ischemia (from 10 to 120 min). The severity of sarcolemmal damage was graded into four classes according to the ultrastructural ischemic changes, as follows: grade 0, normal cells; grade 1, slight ischemic changes in cellular organelles but intact sarcolemma; grade 2, formation of subsarcolemmal blebs, but overall sarcolemmal integrity; and grade 3, sarcolemmal disruption. In the experiment, grade 1 cells decreased and those of grade 3 increased with a longer period of ischemia. The appearance of grade 3 cells was distinct at 30 min of ischemia. This cellular damage proceeded from the subendocardial layer to the subepicardial layer indicating the "wavefront phenomenon." The number of AMDs within the mitochondria increased as the sarcolemmal damage became more severe. It was noteworthy that AMDs could be found in cells with an intact sarcolemma after subjection to 10 min of ischemia. Myoglobin staining of the myocardium obtained after 10 min of ischemia followed by 6 hr of reperfusion revealed no loss of myoglobin, indicating no irreversible cell damage. This finding suggests that the formation of AMDs may occur prior to the disruption of the sarcolemma or irreversible cell damage.

Animals↗
PubMed1989

Detection of mitochondrial membrane damages in myocardial ischemia with ESR spin labeling technique.

The ultrastructure and membrane fluidity were examined in two fractions of myocardial mitochondria isolated from the ischemic region following occlusion of the circumflex coronary artery of the dog. Transmission electron microscopy revealed that 60 min of ischemia produced more structural change in the subsarcolemmal mitochondria than in the intermyofibrillar mitochondria. Changes in the dynamic properties of the mitochondrial membranes were examined using the spin labeling technique with electron spin resonance (ESR). From the ESR spectra, the membrane fluidity of the subsarcolemmal mitochondria was found to decrease significantly after ischemic injury, whereas no difference was observed in intermyofibrillar mitochondria. In addition, a negative correlation between the increase of order parameter S and dysfunction of respiratory responses of subsarcolemmal mitochondria was found. These results suggest that the two fractions of mitochondria in the myocardium showed different responses to acute ischemic injury. The damage to mitochondrial membranes occurred during the period of ischemia.

Animals↗
PubMed1989

Clinical availability of serum fructosamine measurement in diabetic patients with uremia. Use as a glycemic index in uremic diabetes.

Serum fructosamine levels were investigated in patients with uremia undergoing various modes of treatment. The serum fructosamine levels correlated positively with the blood glucose levels determined a week or two earlier. The fructosamine levels were significantly affected by the protein concentration, and those corrected for protein concentrations had a closer correlation to the blood glucose levels than did the uncorrected levels. The corrected fructosamine levels were not significantly different between healthy volunteers and nondiabetic patients with uremia on conservative treatment. In an in vitro system, fructosamine concentrations were hardly affected by urea, which is known to influence the level of hemoglobin A1. These results suggest that serum fructosamine measurement can provide us with reliable information on a short-term glycemic condition, even in azotemic patients. To be more precise, the serum level of fructosamine corrected for protein concentration can be an excellent glycemic index which is not susceptible to over- or dehydration and is of high clinical value, especially in the management of diabetic patients with chronic renal failure.

Adult↗
PubMed1989

[Partial liver transplantation techniques for future clinical application].

Using grafts from brain-dead donors for liver transplantation is a very controversial subject in Japan and those candidates for transplantation who have received livers outside of Japan have been harshly criticized. Under these circumstances, a partial liver transplantation is an attractive method in terms of preserving the donor's life, freshness of the graft and easier donor availability. In other words, for adults with non-cancerous incurable liver disease the donor's left lobe can be transplanted after the recipient has had a left lobectomy, and for children with biliary atresia the whole liver and vena cava can be replaced with a parent's left lobe and iliac vein. Our report concerns the procedures of orthotopic partial liver transplantation for canines and humans.

Animals↗
PubMed1989

Cardiovascular effects of the new cardiotonic agent 1,2-dihydro-6-methyl-2-oxo-5-(imidazo[1,2-a]pyridin-6-yl)-3-pyridine carbonitrile hydrochloride monohydrate. 1st communication: studies on isolated guinea pig cardiac muscles.

Cardiotonic effects and the mechanism of action of 1,2-dihydro-6-methyl-2-oxo-5-(imidazo[1,2-a]pyridin-6-yl)-3-pyridine carbonitrile hydrochloride monohydrate (E-1020), a new cardiotonic agent, were investigated in vitro. E-1020 (10(-7)-10(-4) mol/l) produced a concentration-dependent positive inotropic effect in papillary muscles. E-1020 also caused an increase in contractile force in the right atria which was accompanied by small increases in spontaneous beating rate. The inotropic effect of E-1020 on papillary muscles was not altered by treatment with beta-adrenoceptor or histamine H2-receptor blockade, but was attenuated by the muscarinic agonist, carbachol. E-1020, like isoprenaline (isoproterenol, Iso), restored the contraction of papillary muscles which had been arrested in a high-potassium solution. The inotropic response of papillary muscles to Iso was potentiated by pretreatment with E-1020 at a minimally-effective inotropic concentration (3 x 10(-7) mol/l). E-1020 did not affect the activity of dog kidney Na+, K+-ATPase. On the other hand, the compound specifically inhibited the cyclic AMP-specific isoenzyme (fraction III) of phosphodiesterase and caused an elevation of cyclic AMP content in guinea pig hearts. These results indicate that E-1020 is a potent cardiotonic agent with a minor chronotropic effect and that its inotropic action is mainly mediated by the rise in cardiac cyclic AMP content due to the inhibition of cyclic AMP-specific phosphodiesterase.

Adrenergic beta-Antagonists↗
PubMed1989

[Effect of adriamycin on cell cycle by bromodeoxyuridine-labeling method].

We studied the effect of adriamycin on DNA synthesizing cells from the view point of cell cycle. DNA synthesizing cells were marked by bromodeoxyuridine, which is a known marker for such cells, before administration of adriamycin. Then, the level of this marker was sequentially measured by flow cytometry. At the low concentration (0.01 micrograms/ml), adriamycin caused delay of the shifting time to the S phase 16 hours after administration. The marked cells were accumulated at the G2M phase at a moderate concentration (0.1 micrograms/ml), and blocked at the S phase at the higher concentration (1.0 micrograms/ml).

Bromodeoxyuridine↗
PubMed1989

[Sternotomy wound closure with polyester tapes].

We developed the special polyester tape with Tetron coating for sternal closure. Fifty consecutive open heart cases had the sternum closed with the tapes in the past six months at Nippon Medical School Hospital. There was no sternal infection or mediastinitis postoperatively. The tape closure method was more effective in approximation of sternum than the ordinary wire closure, especially in the case with fragile sternum. Although a long term follow-up is necessary, the result of sternal closure with the polyester tape has been satisfactory.

Humans↗
PubMed1989

[A case report of successful one-stage operation in TGA (group III) with WPW syndrome].

A patient who had received balloon atrioseptotomy and B-T shunt operation previously experienced recurrent episodes of supraventricular tachycardia, and was refractory to medical treatment since the age to 3. At 9 years, the patient underwent intraoperative electrophysiological mapping which confirmed the earliest breakthrough at the crux of posterior septal region. Rastelli's operation and division of posterior septal Kent was simultaneously performed successfully. Post operative ECG was normalized with abolition of delta wave, and PSVT was gone. We concluded that the division of Kent bundle should be simultaneously performed with operative reconstruction in patients with congenital heart disease and WPW syndrome on postoperative care for SVT.

Bundle of His↗
PubMed1989

[Surgical treatment of arrhythmias].

Recently, many types of pacemakers and the surgical interventions based on the fundamental research have been introduced for the treatment of various arrhythmias which are classified as brady- and tachyarrhythmias. In general selection of pacemaker for bradyarrhythmias, VVI pacemaker is used for the patients with atrial fibrillation. However, a more appropriate pacing therapy for this disease would be VVIR. For sick sinus syndrome with normal atrioventricular conduction, AAIR mode is best. DDDR pacemakers are more appropriate for use in the patients with atrioventricular conduction disturbances. A number of surgical procedures been developed specifically for the purpose to abolish refractory tachyarrhythmias. Especially refractory ischemic ventricular tachyarrhythmias (VT) are more difficult to treat surgically than supraventricular tachyarrhythmias. Our operative results indicate that the recurrence of VT results almost in postoperative death in the patients with pleomorphic VT. The direct operation including the implantation of AICD should be considered mainly for those patients. In this field, we considered the progressive ME devices to be essential for the continued improvement of the results.

Arrhythmias, Cardiac↗
PubMed1989

[Experimental study of superior vena caval's reconstruction with ringed E-PTFE grafts].

For evaluating whether 2 types of expanded polytetrafluoroethylene, ringed E-PTFE graft can be utilized for venous reconstruction, especially, for superior vena caval reconstruction or not, the ringed E-PTFE grafts which had 10-15 micron fibril length and 30 micron fibril length were implanted between the innominate vein and the right atrium of the 20 dogs. The grafts were removed for histological and scanning electromicroscopic evaluation at intervals varying from one to twelve postoperative months. Overall patency rate was 62% and severe stenosis at the site of anastomosis was seen in 2 grafts. More than half of the graft showed mild to moderate intimal hyperplasia at the anastomotic sites and the early stage of thrombosis at the middle of the grafts. Mesenchymal cell infiltration was occurred in 46% of the grafts.

Animals↗
PubMed1989

[A case of primary rhabdomyosarcoma of the right ventricle].

A 32-year-old man was admitted to our hospital suffering from cough and bloody sputum. After the preoperative examination, the most suspected diagnosis was either a cardiac myxoma or a pulmonary embolism. At operation, the cavity of main pulmonary trunk was occupied with a tumor growing through the stalk from the outflow tract of right ventricle. The invasive tumor was not completely removed from the pulmonary tract. Rhabdomyosarcoma originating from the right ventricle was confirmed histologically. The patient died on the 199th postoperative day. A necropsy was not conducted. Diagnosis, operative indication and chemotherapy of cardiac rhabdomyosarcoma are discussed in this paper.

Adult↗