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Biomedical subjects

T Asaka

Publications and source records attributed to T Asaka.

At least 37 records · Page 2Linked to original sources
PubMed1996

Immunolocalization of transforming growth factor-beta in the bone tissue.

Fetal mouse calvarias were cultured in a medium containing fetal calf serum, 1,25(OH)2D3 and parathyroid hormone in 5% CO2 incubator at 37 degrees C for 5 days. The calvarias were then fixed in a buffered paraformaldehyde solution and the periostea were removed. A polyclonal antibody against transforming growth factor-beta (TFG-beta) and a second antibody labeled with fluorescein isothiocyanate were used to detect TGF-beta. As a result, a specific staining was observed only in the shielding zone covered by osteoclasts in the bone resorption lacunae and in the extracellular matrix adjacent to the osteoclasts. These findings suggested the local delivery and possible activation of TGF-beta by osteoclasts in tissue.

Animals↗
PubMed1996

Tuberculous tenosynovitis in the elbow joint.

A 74-year-old woman was noted to have a mass lesion near the right elbow joint during medication for pulmonary tuberculosis. After discontinuation of medication, the mass gradually became enlarged with swelling and tenderness of the joint. Radiological evaluation disclosed tenosynovitis with an encapsulated abscess. Microscopic examination and culture of an aspiration biopsy specimen from the abscess showed no microorganisms. However, DNA extracted from the specimen contained mycobacterium tuberculosis DNA, permitting a diagnosis of tuberculous tenosynovitis. Mycobacterium is not always detected in biopsy specimens of tuberculous arthritis and tenosynovitis. In such cases, genetic diagnosis may be of great use.

Abscess↗
PubMed1995

Germanium intoxication with sensory ataxia.

Sensory ataxia in inorganic germanium intoxication is rare. A 63-year-old housewife had taken inorganic germanium preparations at a dosage of 36 mg a day for about 6 years (total dose about 80 g). She subsequently developed difficulty in writing and gait disturbance with peripheral neuropathy and renal involvement. Germanium, which is not usually detected in the non-germanium user, was accumulated in her hair and nails, permitting a diagnosis of inorganic germanium intoxication. The peripheral neuropathy and renal injury were not reversible after discontinuing the preparation. Pneumonia and sepsis then supervened and the patient died. Autopsy findings showed degeneration and loss of the dorsal root ganglion cells and degeneration of the dorsal column of the spinal cord. Two previously reported cases presented with ataxia. These patients took germanium for long periods and/or large quantities like our case. It was supposed that sensory ataxia was induced by chronic and dose dependent toxicity of inorganic germanium.

Aged↗
PubMed1995

Dissociated motor loss syndrome with cavities in the anterior horns.

A 74-year-old man developed proximal muscular weakness and wasting of the left upper extremity without sensory disturbance or myelopathic symptoms. The muscle atrophy had not progressed for a few years. Radiological examination of the spine showed cervical disc herniation. These findings and electrophysiological studies excluded motor neuron diseases, permitting the diagnosis of dissociated motor loss syndrome. Interestingly, delayed computerized tomographic myelography disclosed cavities in the anterior horns of the spinal cord, which coincided with the clinical symptoms. Previous radiological and pathological examinations showed formation of such cavities within the spinal cord resulting from chronic compression, which was followed by ischemic change. In this context, the present case supports ischemia as a cause of dissociated motor loss syndrome.

Aged↗
PubMed1994

Peroneal muscular atrophy with Poland syndrome.

A 22-year-old male college student had a syndactyly between the second and third fingers of his left hand, which was congenitally small in size. His left pectoralis muscles were absent. He first walked at the age of 12 months, but soon developed difficulties in walking due to weakness of the legs. Atrophy and weakness of the legs aggravated gradually. He was diagnosed as having peroneal muscular atrophy and Poland syndrome, an association of which has not been reported before. A small number of similar cases of peroneal muscular atrophy with various skeletal abnormalities in the literature suggest that the association is not incidental, but of clinical significance.

Adult↗
PubMed1994

Structure-activity relationship study of 6-O-methylerythromycin 9-O-substituted oxime derivatives.

In order to develop new-generation macrolide antibiotics active against erythromycin (EM)-resistant strains, a series of 6-O-methyl EM 9-O-substituted oxime derivatives was synthesized and evaluated for antibacterial activity against EM-resistant (S. aureus J-109) and susceptible (S. aureus 209P) strains. To understand how substituents affect the biological activity, the quantitative structure-activity relationships (QSAR) was analyzed using the Hansch-Fujita method. With the EM-resistant strain, the positive coefficient for log P may indicate that higher hydrophobicity of molecules is favorable for antibacterial activity. The negative coefficients of the Sterimol parameters L, B1, and B5 may indicate that long, bulky substituents are unfavorable. With the EM-susceptible strain, the negative coefficient for log P may indicate that hydrophilicity is important for antibacterial activity. A short substituent is also required to improve the activity. Based on the QSAR model, a derivative (87) having an anthracenylmethyl moiety was synthesized to reinforce and confirm the correlation. The activity of 87 against the EM-resistant strain was significant. In QSARs of 6-O-methyl EM-A 9-O-substituted oxime derivatives, the difference of the contribution of log P to the antibacterial activity between EM-resistant and susceptible strains was clearly recognized.

Anti-Bacterial Agents↗
PubMed1993

Chemical modification of erythromycins. IX. Selective methylation at the C-6 hydroxyl group of erythromycin A oxime derivatives and preparation of clarithromycin.

Although erythromycin A contains five hydroxyl groups, regioselective methylation at the C-6 hydroxyl group was achieved to the extent of 90% when a 9-O-substituted erythromycin A 9-oxime was employed as substrate. The methylation and its selectivity are dependent on an O-protecting group at the 9-oxime, solvent, base, and methylating reagent. In particular, the use of a polar aprotic solvent is indispensable for the methylation. Among the 9-oxime derivatives, 2'-O,3'-N-bis(benzyloxycarbonyl)-N-demethylerythromycin A 9-[O-(2-chlorobenzyl)oxime] was the most important intermediate for the synthesis of clarithromycin (6-O-methylerythromycin A).

Clarithromycin↗
PubMed1988

Primary pulmonary artery sarcoma. Report of two autopsy cases studied by immunohistochemistry and electron microscopy, and review of 110 cases reported in the literature.

Two cases of primary pulmonary artery sarcoma are reported. The patient in the first case was a 61-year-old male with a two-year history of cough and exertional dyspnea, who died of intractable cardiac failure two months after admission without establishment of a diagnosis related to the etiology of cardiac failure. Autopsy revealed a sessile tumor within the pulmonary trunk and a solitary metastatic lesion in the lung. Histologic, immunohistochemical and electron microscopic studies were performed and a diagnosis of malignant mesenchymoma was made. The patient in the second case was a 32-year-old male complaining of exertional dyspnea and back pain. Radiologic studies indicated a mediastinal tumor involving the pulmonary artery. Exploratory thoracotomy revealed that the mediastinal mass arose from the left pulmonary artery. He died of respiratory failure 26 months after onset of his initial symptoms. Histologic, immunocytochemical and electron microscopic studies of both surgical and autopsy materials revealed a malignant fibrous histiocytoma. One hundred ten previously reported cases of this tumor are reviewed, and its clinicopathologic and morphologic features and probable histogenesis are discussed.

Adult↗
PubMed1987

[Echocardiographic characteristics and clinical significance of the spontaneous contrast echoes].

Spontaneous echocardiographic contrast is caused by increased ultrasonic density in the cardiac chambers or great vessels, or both, with the characteristic flow pattern of blood, but in the absence of any intravascular injections. This study demonstrated the clinical features and characteristics of the echocardiographic findings of eight patients with spontaneous contrast echoes. Spontaneous contrast echoes were observed in the right heart in five patients, and in the left heart in two. In one patient spontaneous contrast echoes were observed in the right and left heart. All six patients with spontaneous contrast echoes in the right heart had impaired liver function. In these patients, we observed that spontaneous contrast reaching the heart via the hepatic vein on two-dimensional echocardiography. In one patient with atrial septal defect, these contrast echoes were also recognized in the superior mesenteric vein and portal vein. Since capillary beds normally remove ultrasound contrast, the failure of this function suggests porta-systemic shunting in or around the liver. All three patients with spontaneous contrast echoes in the left heart had prosthetic valve dysfunction including paravalvular or transvalvular regurgitation, and consequent hemolysis. Under these conditions, water-vapor bubbles may be formed because of an exhaust pressure decrease due to the Bernoulli effect, or gases may be released from erythrocytes during hemolysis. These water-vapor bubbles or gases could be the cause of spontaneous contrast echoes in the left heart. In conclusion, spontaneous contrast echoes in the right heart are produced by gas absorbed from the intestine because of porta-systemic shunting. The cause of spontaneous left-sided heart echo contrast may be related to prosthetic valve regurgitation, and consequently to hemolysis.

Adult↗
PubMed1986

[Mechanical and electrocardiographic sequence of coronary artery occlusion: an echocardiographic study during coronary angioplasty].

The detection of regional myocardial dysfunction due to acute ischemic event has been limited almost entirely to experimental animal models. In human subjects, it has been limited to the observations during spontaneously-occurring or exercise-induced ischemic events. Recently, percutaneous transluminal coronary angioplasty (PTCA) provides an opportunity to study such dysfunction as the result of repeated interruptions of coronary blood flow. Echocardiograms and electrocardiograms were simultaneously recorded immediately before, during, and after 21 episodes of complete interruptions of coronary blood flow by PTCA in 11 patients. No patient had asynergy of the left ventricle either by two-dimensional echocardiography (2DE) or angiography. All patients had isolated single coronary artery stenosis including the left anterior descending artery in nine, left circumflex artery in one and right coronary artery in one. Recordings of M-mode and 2DE were successfully obtained in 10 patients. After balloon inflation, regional asynergy in the distribution of the instrumented coronary artery appeared in all 10 patients. Hypokinesis developed 9 +/- 3 (means +/- SD) sec after balloon inflation and progressed rapidly to akinesis or dyskinesis. At the same time, decreased systolic thickening of the left ventricular wall appeared in some patients in relation to the development of regional asynergy. However, systolic thinning of the left ventricular wall was not noted in all. The regional asynergy preceded ischemic electrocardiographic changes and had no relation to chest pain. Left ventricular wall motion began to normalize 12 +/- 3 sec after balloon deflation. Thereafter, transient hyperkinesis of the left ventricle developed. The first ischemic electrocardiographic change was a negative U wave which appeared 13 +/- 7 sec after coronary occlusion and remained 3 to 4 sec. Tall T waves were recorded at 28 +/- 12 sec and significant ST elevations developed 31 +/- 11 sec, after balloon inflation. These electrocardiographic changes invariably occurred only after the onset of wall motion abnormalities. Normalization of T waves was recognized at 17 +/- 16 sec and ST segment deviation were no longer present at 18 +/- 10 sec, after reperfusion. These electrocardiographic changes also preceded normalization of regional myocardial dysfunction. In conclusion, left ventricular wall motion abnormalities after coronary occlusion invariably precede the electrocardiographic changes, and begin to normalize after reperfusion prior to the electrocardiographic recovery.

Adult↗
PubMed1986

[Non-rheumatic multivalvular regurgitation in an older population: a pulsed Doppler echocardiographic study].

To assess the incidence of valvular regurgitation, 180 patients more than 40 years of age without cardiac symptoms were studied by pulsed Doppler echocardiography. The 180 patients were categorized by age as group 1, 40 to 49 years; group 2, 50 to 59 years; group 3, 60 to 69 years; group 4, 70 to 79 years; and group 5, more than 80 years of age. The incidence of valvular regurgitant flow signals increased significantly with age. Multivalvular regurgitation were often detected in groups 4 and 5. Furthermore, acoustically silent regurgitation at each valve was frequently noted (71 of 85 cases with valvular regurgitant flow signal: 84%). Mitral valve prolapse was diagnosed by two-dimensional echocardiography in 27 patients, but a mid-systolic click or pansystolic murmur with late-systolic accentuation was not noted. In conclusion, valvular regurgitations were common in the aged who lacked auscultatory findings.

Adult↗
PubMed1986

[Value of right ventricular and atrial collapse in identifying cardiac tamponade].

Collapse of the right ventricle and right and left atria is observed in cardiac tamponade. To assess the diagnostic value of each collapse component in identifying cardiac tamponade, two-dimensional and M-mode echocardiograms were recorded simultaneously with the measurement of intrapericardial pressure in five patients as they underwent pericardiocentesis. Before pericardiocentesis, each patient had evidence of right ventricular and right atrial collapse. In addition, left atrial collapse was observed in four patients. During pericardiocentesis, left atrial collapse initially resolved accompanied by a drop in pressure in the pericardial sac. Continuous drainage of pericardial effusion resulted in significant symptomatic improvement and the cessation of paradoxical pulse at the point of resolution of right ventricular collapse. However, right atrial collapse persisted after resolution of right ventricular collapse, but it was absent when pericardiocentesis was completed. Injection of saline solution with heparin into the pericardial sac for cleansing initially caused right atrial collapse, while right ventricular collapse developed with the appearance of cardiac tamponade. In one patient, the simultaneous recording of right ventricular and intrapericardial pressures and two-dimensional echocardiograms demonstrated that right ventricular collapse occurred early in diastole, when intrapericardial pressure exceeded right ventricular pressure. In conclusion, right ventricular collapse is the most reliable sign of cardiac tamponade. Right atrial collapse occurs in the early stage of cardiac tamponade. Left atrial collapse appears very late in the course of hemodynamic deterioration due to cardiac tamponade.

Adult↗
PubMed1985

[Functional transvalvular regurgitation in patients with Björk-Shiley aortic valves: a pulsed Doppler echocardiographic study].

It is well known that a small amount of regurgitation occurs through Björk-Shiley valves. Obviously, this functional regurgitation is related to the construction of the Björk-Shiley valve, wherein the disc does not overlap the ring, but fits within its orifice, leaving a minimal space between the edge of the disc and the ring. The aim of this study was to evaluate the clinical significance of regurgitation in patients having Björk-Shiley valves in the aortic position by pulsed Doppler echocardiography. The study group consisted of 46 patients with normally functioning valves and five patients with malfunctioning valves. Valve dysfunction resulted from paravalvular regurgitation in three, and thrombosed valves in two (confirmed by surgery and angiography). Using pulsed Doppler echocardiography, aortic regurgitation was observed in 29 of the 46 normally functioning Björk-Shiley aortic valves. Among these, regurgitant flow signals were constantly located in the vicinity of the valve ring in the left ventricular outflow tract. Therefore, these regurgitant flow signals were considered to represent functional regurgitation of the Björk-Shiley valve. Aortography was performed for 11 of the 46 normally functioning Björk-Shiley valves, and there was minimal transvalvular regurgitation in all. In all of the five malfunctioning Björk-Shiley aortic valves, aortic regurgitant flow signals were detected by pulsed Doppler echocardiography, and the maximal distance of the regurgitant flow signals from the Björk-Shiley valve ring was more than 0.5 cm. However, it was difficult to differentiate transvalvular regurgitation from paravalvular regurgitation using pulsed Doppler technique alone.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Valve↗
PubMed1985

[Tricuspid regurgitation evaluated by Doppler hepatic vein flow patterns].

Hepatic vein flow can be reliably measured because Doppler sampling volumes are easily oriented parallel with the course of the hepatic vein. In this study, the relationship between the Doppler signal in the hepatic vein and the external jugular vein pulse was evaluated, and the contribution of the Doppler echocardiography to the quantitative diagnosis of tricuspid regurgitation was also assessed. The subjects consisted of five healthy persons, four patients with lone atrial fibrillation, 27 patients who underwent cardiac surgery, and 34 patients with tricuspid regurgitation. The severity of the regurgitation was judged by right ventriculography and inferior caval angiography. The pattern of the Doppler hepatic vein flow mimicked that of the jugular phlebogram in each patient. The normal hepatic vein flow consisted of two forward flows toward the heart; one in systole; the other, in diastole, and one retrograde flow toward the liver during atrial contraction. In patients with lone atrial fibrillation, a systolic backward flow toward the liver or a decrease in the systolic forward flow was observed, though there was no tricuspid regurgitation. In patients who had cardiac surgery, a systolic backward flow toward the liver or a decrease in the systolic forward flow was usual. However, a prominent systolic backward flow toward the liver was observed in patients with severe tricuspid regurgitation, and a decreased systolic forward flow toward the heart was observed in patients with moderate tricuspid regurgitation in sinus rhythm. We concluded that Doppler measurement of hepatic vein flow does not contribute to the diagnosis of tricuspid regurgitation in the presence of atrial fibrillation or in postoperative conditions, but that it is useful in identifying severe tricuspid regurgitation.

Coronary Artery Bypass↗
PubMed1985

[An intermittent mid-diastolic musical murmur indicating aortic regurgitation: report of a case].

An unusual mid-diastolic musical murmur developed soon after cardiac catheterization of a 55-year-old man with mitral stenosis. His physical findings consisted of an accentuated first heart sound, an opening snap and a grade 3/6 mid-diastolic rumbling murmur. No early diastolic murmur was audible. However, soon after cardiac catheterization, a mid-diastolic "cooing" murmur at a frequency of 200 cycles/sec developed. This murmur resolved with the patient in the sitting position, or by leg raising. With Valsalva or Müller maneuvers this murmur was abolished transiently, and it disappeared on administering either amyl nitrite or methoxamine. Echocardiography revealed early diastolic vibrations in the aortic valve. Pulsed Doppler echocardiograms revealed harmonic signals of the aortic cusp at a fundamental frequency of 200 cycles/sec. These harmonic signals could be recorded only in mid-diastole. The frequency patterns of the murmur and the Doppler signals were identical; therefore, the murmur was judged to be produced by aortic valve vibrations. Furthermore, resonance of cardiac structures which accentuate the murmur might be related to the occurrence of this murmur. Pulsed Doppler echocardiography is helpful in identifying the site of origin of this musical murmur.

Aortic Valve Insufficiency↗