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Biomedical subjects

M Takao

Publications and source records attributed to M Takao.

At least 127 records · Page 7Linked to original sources
PubMed1994

The development of the endothelin-1-induced gastric ulcer: time sequence analysis of morphologic changes.

We have recently reported that the submucosal injection of endothelin-1 induces gastric ulcers in rats. In the present study, we have examined the time sequence of the macroscopic, histologic and ultramicroscopic features of the formation and development of the gastric ulcer induced by endothelin-1 (100 pmol submucosally). In rats, we examined the effect of endothelin-1 on the gastric mucosa macroscopically, on the gastric mucosal cells and vessels by light microscopy and on the ultra-structure of the gastric mucosal surface and of the gastric glands by electron microscopy. Gastric mucosal changes were evaluated 1, 4, 30 minutes, 1, 4, 8, 16, 20, 24 hours and 2, 4, 7, 14, 21 days after teh submucosal injection of endothelin-1. Application of endothelin-1 was immediately followed by arterial vasoconstriction and venous dilatation, 5 minutes later by interstitial haemorrhage and 30 minutes later by demise of epithelial cells. Electron microscopy showed almost complete exfoliation of the inter-pit cells 30 minutes after the injection. By 1 hour, superficial redness, apoptosis of superficial cells and loss of the intra-pit cells was detected. By 8 hours, there was mucosal haemorrhage and complete loss of intra-pit cells from the basal part of the gastric glands. Forty-eight hours later, there was a deep gastric ulcer with penetration of the muscularis mucosae. By 4 days, the ulcers had entered the chronic phase and by 1 week abnormal glands were covering the area of damage with no mucous production. By 3 weeks the damaged area was still structurally abnormal. The results of this study suggest that injury to the microvasculature may initiate the degenerative and structural changes of the gastric mucosa that lead to the production of this novel type of experimental gastric ulcer in rats.

Animals↗
PubMed1993

A 127 kDa component of a UV-damaged DNA-binding complex, which is defective in some xeroderma pigmentosum group E patients, is homologous to a slime mold protein.

A cDNA which encodes a approximately 127 kDa UV-damaged DNA-binding (UV-DDB) protein with high affinity for (6-4)pyrimidine dimers [Abramic', M., Levine, A.S. & Protic', M., J. Biol. Chem. 266: 22493-22500, 1991] has been isolated from a monkey cell cDNA library. The presence of this protein in complexes bound to UV-damaged DNA was confirmed by immunoblotting. The human cognate of the UV-DDB gene was localized to chromosome 11. UV-DDB mRNA was expressed in all human tissues examined, including cells from two patients with xeroderma pigmentosum (group E) that are deficient in UV-DDB activity, which suggests that the binding defect in these cells may reside in a dysfunctional UV-DDB protein. Database searches have revealed significant homology of the UV-DDB protein sequence with partial sequences of yet uncharacterized proteins from Dictyostelium discoideum (44% identity over 529 amino acids) and Oryza sativa (54% identity over 74 residues). According to our results, the UV-DDB polypeptide belongs to a highly conserved, structurally novel family of proteins that may be involved in the early steps of the UV response, e.g., DNA damage recognition.

Amino Acid Sequence↗
PubMed1993

Carcinosarcoma of the prostate.

A unique case of carcinosarcoma of the prostate occurring in a 32 year old man is presented. This is the youngest case reported to date among nine well-documented examples. The patient underwent a total prostatectomy under the diagnosis of prostatic sarcoma. Despite adjuvant chemotherapy and full-dose radiotherapy being undertaken, the patient died from multiple lung metastases about 8 months after the operation. The surgically resected primary tumor was composed of two histologically distinct elements, these being an undifferentiated carcinoma and a sarcoma with various mesodermal components. These elements were intimately intermingled and transitional forms were often noticed. The sarcomatous portion contained myxoid areas, spindle cell sarcomas with nuclear palisading, areas of osteoid formation and small islands of chondromatous differentiation. The pathogenesis of this complex neoplasm is discussed, and it is suggested that vestigial embryologic Müllerian mesodermal tissue may be capable of diverse differentiation.

Adult↗
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

Laser measurement of myocardial blood flow.

A He-Ne laser flowmeter (wavelength: 632.8 nm, power: 2 mW) has already been used to measure blood flow in skin, muscle, and mucosa. However, the application of this flowmeter for the beating heart has been left undeveloped due to its difficulty. For the purpose of establishment of the laser measurement of myocardial blood flow, we redesigned a flow probe to be small and light and used a connecting paste to support the subepicardial flow probe. After resolving many obstacles, the noninvasive and real-time blood flow measurement of the beating heart was made possible. The flow volume in subendocardial myocardium was greater than the volume in subepicardial myocardium, and the average ratio of subendocardial flow to subepicardial flow was 1.62 +/- 0.21.

Animals↗
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↗