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Biomedical subjects

M Takao

Publications and source records attributed to M Takao.

At least 19 recordsLinked to original sources
PubMed1992

A case of asymptomatic cortisol producing adrenal adenoma.

We describe a man without the clinical findings of Cushing's syndrome, but who harbored an incidentally found cortisol-producing adrenal adenoma. On adrenal 131I-adsterol imaging, there was good uptake to the nodule, but no visualization of the contralateral adrenal. No abnormalities were found in the basal plasma cortisol, ACTH, urinary free cortisol and 17OHCS. However, dynamic hormone assessment revealed the existence of abnormal cortisol secretion: no suppression to dexamethasone, incomplete response to human corticotropin-releasing hormone, and lack of diurnal variation in plasma cortisol. Left adrenalectomy was performed with the diagnosis of cortisol-producing adrenal tumor. The pathological finding was an adrenal adenoma, and the perifusion of the excised tissues revealed a negligible response of the tumor tissue to ACTH though the residual normal cortex responded. Postoperative course was uneventful without replacement therapy with cortisol. It is suggested that the tumor autonomously produced a small amount of cortisol not only insufficient to provide clinical Cushing's syndrome, but also to provide typical suppression of hypothalamo-pituitary corticotroph-adrenal system.

Adenoma↗
PubMed1992

[Urodynamic studies before and after gradual urethral dilatation with metal sounds for female urethral stricture].

We evaluated the urodynamics in women with urethral stricture after urethral dilatation. A total of 16 patients underwent treatment with gradual urethral dilatation at increasing intervals (2 weeks, 1 month, 3 months and 6 months). Their urethra was dilated up to 30 F. with metal sounds. Urethral calibration with bougie à boule, uroflowmetry and urethral pressure profile were performed before urethral dilatation and 1 week after the last dilatation. The urethral caliber was increased from 18.1 +/- 0.6 F. to 23.5 +/- 1.0 F. (P less than 0.005), average flow rate from 9.4 +/- 0.8 ml/sec to 11.2 +/- 1.1 ml/sec (P less than 0.025) and maximum urethral pressure with a full bladder decreased from 105.4 +/- 9.4 cmH2O to 87.5 +/- 10.5 cmH2O (P less than 0.05). With gradual urethral dilatation with metal sounds, (1) the urethra was significantly dilated, (2) maximum urethral pressure was significantly decreased and (3) average flow rate was significantly increased.

Adult↗
PubMed1992

[Reconstructive surgery for mitral regurgitation caused by degenerative disease--indications for expansion and early clinical outcomes].

Between January 1983 and June 1990, there were 48 patients who underwent surgery for mitral regurgitation due to degenerative diseases. Among these, 20 patients received mitral valve repair. Overall operative mortality was 5% for patients who underwent valve repair, and 7.1% for those who underwent valve replacement. We standardized a maneuver for valve repair in August 1988 in an attempt to expand its indications. There were 35 patients who underwent surgery prior to that date (group 1), and 13 patients after that date (group 2). There were nine patients (25.7%) in group 1 and 2 patients (84.6%) in group 2 who underwent valve repair. Among these, one patient (11%) in group 1 died within 30 days after the operation, but there were no surgical deaths for any patients in group 2. In addition, one patient (11%) in group 1 and one (9%) in group 2 required another operation for valve replacement. Doppler echocardiographic studies performed postoperatively in 18 patients who had undergone valve repair showed that 13 (72.2%) had no regurgitation, 4 (22.2%) had trivial regurgitation, and 1 (5.6%) had mild regurgitation. Postoperative valve area as determined by continuous-wave Doppler echocardiography was 3.7 +/- 1.1 cm2 (mean +/- SD) for patients who had undergone reconstruction and 3.1 +/- 0.7 cm2 for those who had undergone replacement.

Adolescent↗
PubMed1991

Unique characteristics of superoxide dismutase of a strictly anaerobic archaebacterium Methanobacterium thermoautotrophicum.

The superoxide dismutase (SOD) gene of Methanobacterium thermoautotrophicum (Takao, M., Oikawa, A., and Yasui, A. (1990) Arch. Biochem. Biophys. 283, 210-216), a strictly anaerobic archaebacterium, was expressed in Escherichia coli. The gene product accounted for more than 30% of the host's soluble protein. The purified protein was an active iron-containing tetrameric SOD with specific activity similar to known manganese-containing SODs (MnSODs) of aerobic archaebacteria. Although M. thermoautotrophicum SOD is an iron-containing SOD (FeSOD), it resembles MnSODs in amino acid sequence as judged by criteria distinguishing FeSODs from MnSODs. Moreover, M. thermoautotrophicum SOD is resistant to azide and hydrogen peroxide as MnSODs are, suggesting that its evolution is distinct from known eubacterial FeSODs.

Amino Acid Sequence↗
PubMed1991

The enhancement of myocardial protection through an acalcemic storage solution containing nicardipine, a potent calcium channel blocker. A basic study using rat ventricular myocytes.

Adult rat ventricular myocytes were used as a model system for investigating the direct effects of nicardipine, a potent calcium-channel blocker, on preservation of the heart during periods of simple cold storage. Cells were stored at 4 degrees C for 24 hr with an acalcemic storage solution. The superfusate then was exchanged with hypoxic Tyrode solution (1.8 mmol/L CaCl2). After 2 hr of hypoxia at 20 degrees C, cells were reoxygenated and simultaneously warmed to 37 degrees C. The addition of nicardipine to both the storage solution and Tyrode solution resulted in the highest percentage of viable cells (70.5%). Using either the storage solution or Tyrode solution containing the compound, the percentages of viable myocytes were 51.9% and 52.2%, respectively. In the absence of the drug in either solution, the percentage was 38.0%. The effect of diltiazem, another potent calcium-channel blocker, was examined using the same experimental procedure. The addition of diltiazem to Tyrode solution elevated the viability of ventricular myocytes, but addition to the storage solution showed no cardioprotective effect. Moreover, the addition of 8-bromo cyclic GMP to the storage solution resulted in a cardioprotective effect. These results suggested that nicardipine exerts a direct effect on myocardial protection in hypothermic and acalcemic storage solution and that the pharmacological effect of nicardipine depends on a mechanism other than its calcium-channel blocking action.

Animals↗
PubMed1991

[The effects of gravity load on the canine kidney].

In Self-defense Force Hospitals we often treat pilots with renal stones who will be exposed to high gravity (G) load after the treatment. Because the regulation prohibits the flight of a pilot with urolithiasis, the stone must be removed completely by noninvasive procedure. Percutaneous nephrolithotomy, therefore, is one of the treatment of choice in such patients. The effect of G load on the kidney, in particular, on the renin-angiotensin-aldosterone (R-A-A) system and the safety of percutaneous nephrolithotomy in a pilot who is exposed to high G load have not been adequately investigated. In this study, I examined the effect of G load in canine kidney model. The effect of G load on R-A-A system: Twenty-two adult mongrel dogs of a mean weight of 10.9 kg. maintained on a normal Na+ intake were studied. To dogs in the sitting position, high G load was given. The exposure to G load consisted of maximum load of 8 G for 45 seconds with the onset ratio of 0.1 G/sec. for group 1, and 5 courses of maximum G load of 8 G for 10 seconds with the onset ratio of 2.5 G/sec., followed by 1.5 G for 60 seconds for group 2. Plasma renin activity was unchanged in group 1, but it increased in group 2. Plasma aldosterone increased from 68.6 +/- 17.9 to 252.0 +/- 56.4 pg/ml (p less than 0.005) in group 1. and from 191.8 +/- 40.6 to 479.2 +/- 76.0 pg/ml (p less than 0.005) in group 2 after G load. Angiotensin II decreased from 129.0 +/- 19.4 to 84.7 +/- 19.1 pg/ml (p less than 0.05) after G load in group 2. These data suggest that the increase in plasma aldosterone after G load in independent of the renin-angiotensin system. It is considered that the alteration of R-A-A system was caused by the change of blood flow distribution due to the effect of G load. The tolerance to G load on the kidney following subcutaneous nephrostomy: Unilateral subcutaneous nephrostomies were carried out under pentobarbital anesthesia in 15 adult female mongrel dogs. Each experimental dog was exposed to high G load 2 or 4 weeks after removal of the nephrostomy tube. Excretory urography, renal angiography and renal function tests were performed before and after G load. Excretory urograms demonstrated no remarkable changes at all after G load in all dogs. Renal angiograms revealed small renal infarction along the nephrostomy tract in almost all dogs.(ABSTRACT TRUNCATED AT 400 WORDS)

Aerospace Medicine↗
PubMed1991

[Percutaneous nephrolithotomy in horseshoe kidney].

Two patients with renal pelvic stone in a horseshoe kidney who underwent a percutaneous nephrolithotripsy (PNL) are presented. Case 1 was a 36-year-old man with a 20 x 12 mm right renal pelvic stone in a horseshoe kidney. Case 2 was a 47-year-old man who had been followed up at our clinic for a horseshoe kidney and was found to have a 15 x 10 mm left renal pelvic stone. We found that percutaneous removal of renal pelvic stones can be performed safely in a horseshoe kidney. It appears that to remove stones from the renal pelvis in a horseshoe kidney 4 items must be considered. 1) The anatomical relationships of the horseshoe kidney to other viscera and blood vessels should be confirmed before surgery utilizing computerized tomography or ultrasound sonography. 2) The occlusion ureteral catheter should be inserted up to the renal pelvis to prevent small fragments from falling into the ureter. 3) The rigid nephroscopy should be introduced through the most appropriate calyx, so that its manipulation could be limited. 4) The fragmentation of stones should be performed from the peripheral surface of a stone to prevent from migrating into another calyx. We believe this is only the sixth and seventh documented cases involving a horseshoe kidney.

Adult↗
PubMed1990

Characterization of a superoxide dismutase gene from the archaebacterium Methanobacterium thermoautotrophicum.

A gene encoding superoxide dismutase (SOD) was cloned from the archaebacterium Methanobacterium thermoautotrophicum, the first example from an anaerobic bacterium. The deduced amino acid sequence showed overall similarity to sequences of known Mn- and Fe-SODs from aerobic organisms. Judging from a detailed sequence comparison, the cloned SOD gene is classified as Mn-SOD. By comparison of Mn-SOD sequences among various species it was suggested that archaebacterial superoxide dismutase is a direct descendant of a primordial enzyme. Between a putative promoter and the start codon there is an inverted repeat sequence which is also found in the counterpart of Halobacterium halobium.

Amino Acid Sequence↗
PubMed1990

Increased UV sensitivity of Escherichia coli cells after introduction of foreign photolyase genes.

High-expression plasmids for photolyase (phr) genes from the bacteria Escherichia coli, Anacystis nidulans, Streptomyces griseus and Halobacterium halobium and the yeast Saccharomyces cerevisiae were constructed and introduced into E. coli phr recA cells. As previously reported, al introduced phr genes provided the host cells with photoreactivation-repair activity and the introduced E. coli phr gene rendered the host cells more UV-resistant in the dark. E. coli cells harboring foreign phr genes, however, were found to be more sensitive to UV light in the dark than cells containing the vector plasmid only. These differences in UV sensitivity in the dark disappeared when the host cells had an additional mutation, uvrA, suggesting that the foreign photolyases inhibited the E. coli excision-repair system.

Base Sequence↗
PubMed1990

[Evaluation of aortocoronary bypass operation using a He-Ne laser flowmeter--comparison between internal mammary artery grafts and saphenous vein grafts].

It was very difficult to measure myocardial blood flow in clinical cases. Recently, a He-Ne laser doppler flowmeter was developed, and we made it possible to measure the pre-and post-operative myocardial blood flow in cases of coronary artery bypass grafting (CABG). We applied a laser flowmeter to 30 cases of bypass grafting to the left anterior descending coronary artery (18 cases with IMAG and 12 cases with SVG). The preoperative myocardial blood flow at the right ventricular anterior wall was 77 +/- 15 ml/min/100 gr, and the postoperative flow at the same point was 81 +/- 12 ml/min/100 gr. There was no significant change between the pre-operative value and the postoperative one. Myocardial blood flow at the left ventricular anterior wall in SVG group significantly increased from the preoperative value of 58 +/- 11 ml/min/100 gr to the postoperative value of 86 +/- 9 ml/min/100 gr (p less than 0.001). In IMAG group, myocardial blood flow at the left ventricular anterior wall similarly increased from 73 +/- 14 ml/min/100 gr to 83 +/- 15 ml/min/100 gr (p less than 0.01). The postoperative value of IMAG group was almost equal to the value of SVG group. The increased rate of myocardial blood flow at the left ventricular anterior wall was 52 +/- 32% in SVG group and 18 +/- 12% in IMAG group. These rates were obviously distinguished from the increased rate at the right ventricular anterior wall.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗