Search PubMed⌕ Search

Biomedical subjects

T Yoshimoto

Publications and source records attributed to T Yoshimoto.

At least 541 records · Page 30Linked to original sources
PubMed1994

Isolation and characterization of the prolyl aminopeptidase gene (pap) from Aeromonas sobria: comparison with the Bacillus coagulans enzyme.

The Aeromonas sobria pap gene encoding prolyl aminopeptidase (PAP) was cloned. It consists of 425 codons and encodes a homotetrameric enzyme of 205 kDa. The purified enzyme showed an almost absolute specificity for amino-terminal proline. Proline and hydroxyproline residues from many peptide and amide substrates could be easily removed, while no activity was detected for substrates having other amino terminals. The enzyme was very similar to that from Bacillus coagulans in many aspects, such as the strong inhibition caused by PCMB and the weak or no inhibition caused by DFP and chelators, respectively. However, these enzymes show only 15% identity in their amino acid sequences. Differences were also observed in their molecular weight, stability and activity toward some peptide substrates. When aligning the deduced amino acid sequence with known sequences from other microorganisms, conserved sequences were found at the amino-terminal region; the significance of these conserved regions is discussed. Based on the results of this work, and on the studies available to date, the occurrence of at least two types of PAPs is postulated. One group would be formed by the Bacillus, Neisseria, and Lactobacillus enzymes, and the other by enzymes such as the Aeromonas PAP.

Aeromonas↗
PubMed1994

Prolyl aminopeptidase is not a sulfhydryl enzyme: identification of the active serine residue by site-directed mutagenesis.

Prolyl aminopeptidase (PAP) has been classified as a sulfhydryl enzyme on the basis of its high sensitivity to p-chloromercuribenzoate and heavy metals. Recently, however, the possibility of PAP being instead a serine enzyme has been raised as a result of two observations--the conservation of some residues among the PAPs hitherto sequenced, and a similarity to some serine hydrolases. This is the first report describing an attempt to identify the active residue by site-directed mutagenesis. The pap genes from Bacillus coagulans and Aeromonas sobria, were used for the study. The changes made were Cys62Ser and Ser101Ala for the first enzyme, and Thr92Ala and Ser146Ala for the second. For both enzymes, only the changes made on the serine residues resulted in their complete inactivation, indicating that PAP is a serine peptidase.

Aeromonas↗
PubMed1994

Cloning and high-level expression of the glutathione-independent formaldehyde dehydrogenase gene from Pseudomonas putida.

A DNA fragment of 485 bp was specifically amplified by PCR with primers based on the N-terminal sequence of the purified formaldehyde dehydrogenase (EC 1.2.1.46) from Pseudomonas putida and on that of a cyanogen bromide-derived peptide. With this product as a probe, a gene coding for formaldehyde dehydrogenase (fdhA) in P. putida chromosomal DNA was cloned in Escherichia coli DH5 alpha. Sequencing analysis revealed that the fdhA gene contained 1,197-bp open reading frame, encoding a protein composed of 399 amino acid residues whose calculated molecular weight was 42,082. The transformant of E. coli DH5 alpha harboring the hybrid plasmid, pFDHK3DN71, showed about 50-fold-higher formaldehyde dehydrogenase activity than P. putida. The predicted amino acid sequence contained several features characteristic of the zinc-containing medium-chain alcohol dehydrogenase (ADH) family. Most of the glycine residues strictly conserved within the family, including a Gly-Xaa-Gly-Xaa-Xaa-Gly pattern in the coenzyme binding domain, were well conserved in this enzyme. Regions around both the catalytic and the structural zinc atoms were also conserved. Analyses of structural and enzymatic characteristics indicated that P. putida FDH belongs to the medium-chain ADH family, with mixed properties of mammalian class I and III ADHs.

Alcohol Dehydrogenase↗
PubMed1994

Does plasma immunoreactive ouabain originate from the adrenal gland?

It was reported recently that the endogenous digitalis-like factor ouabain may mainly originate from the adrenal gland. To ascertain the pathophysiological significance of endogenous ouabain and to examine if it originates in the adrenal gland, we determined plasma immunoreactive ouabain levels in patients with various cardiovascular and endocrine diseases. Plasma immunoreactive ouabain levels were also determined in the adrenal venous blood by adrenal venous sampling. Plasma immunoreactive ouabain levels were significantly increased in patients with essential hypertension, primary aldosteronism, Cushing's syndrome, pheochromocytoma, acromegaly, and chronic renal failure. Plasma immunoreactive ouabain levels were decreased in patients with primary aldosteronism after unilateral adrenalectomy, acromegaly after pituitary adenomectomy, and chronic renal failure after hemodialysis. Plasma immunoreactive ouabain levels in patients after bilateral adrenalectomy were similar to those in healthy subjects. There was no significant step-up of immunoreactive ouabain levels in the adrenal vein from the peripheral vein in three patients, whereas one patient with hypertension and right adrenal tumor but without any known adrenal hormone excess showed higher plasma immunoreactive ouabain levels in the right adrenal vein than those in the peripheral vein. These results suggest an important pathophysiological significance of endogenous ouabain in various cardiovascular and endocrine diseases. It is unlikely that the adrenal gland is a major source of plasma ouabain, although a possible excess production of ouabain by the adrenal tumor remains to be elucidated.

Adrenal Gland Neoplasms↗
PubMed1994

Atrial and brain natriuretic peptides in cardiovascular diseases.

The human heart secretes both atrial natriuretic peptide and brain natriuretic peptide. This study attempts to clarify the pathophysiological significance of the peptides in cardiovascular diseases. Using immunoradiometric assay, plasma brain natriuretic peptide and atrial natriuretic peptide levels in essential hypertension, various secondary hypertension, chronic renal failure, chronic heart failure during cardiac pacing, and acute myocardial infarction were determined. Mean plasma brain natriuretic peptide and atrial natriuretic peptide levels in healthy subjects were 3.7 +/- 0.3 and 5.7 +/- 0.3 pmol/L, respectively, and increased as a function of age. Plasma brain natriuretic peptide levels showed a larger increase than atrial natriuretic peptide levels in various cardiovascular diseases. In chronic renal failure, whereas plasma atrial natriuretic peptide levels decreased significantly after hemodialysis and were correlated with the changes in body weight, changes in plasma brain natriuretic peptide levels were less prominent and did not show such a correlation. In chronic heart failure, both basal plasma brain natriuretic peptide and atrial natriuretic peptide levels were also significantly elevated. However, in response to acute ventricular or atrial pacing, brain natriuretic peptide levels did not show any increase in contrast to the marked increase of atrial natriuretic peptide levels. In acute myocardial infarction, brain natriuretic peptide levels showed more prominent changes than atrial natriuretic peptide levels and were correlated with serum levels of creatine kinase and cardiac myosin light chain I in most patients. These results suggest that both brain and atrial natriuretic peptides play an important role in the regulation of cardiovascular homeostasis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenal Gland Neoplasms↗
PubMed1994

Basilar artery occlusion caused by thrombosis of atherosclerotic fusiform aneurysm of the basilar artery.

BACKGROUND: Basilar artery occlusion caused by thrombosis of atherosclerotic fusiform aneurysm of the basilar artery is rare. We present a case confirmed by 6 years of follow-up and autopsy. CASE DESCRIPTION: A 63-year-old man suffered from brain stem infarction. Computed tomography and angiography showed a fusiform aneurysm on the proximal portion of the basilar artery. At the time of the third attack 5 years later, complete thrombosis of the aneurysm was found, and the proximal basilar artery was occluded. On autopsy, an atherosclerotic aneurysm 15 mm in diameter was found. CONCLUSIONS: A large atherosclerotic fusiform aneurysm of the basilar artery often causes brain stem infarction and involves a risk of complete thrombosis of the aneurysm and subsequent parent artery occlusion.

Aged↗
PubMed1994

Evidence that a leukocyte type of 12-lipoxygenase is expressed and regulated by angiotensin II in human adrenal glomerulosa cells.

The 12-lipoxygenase (LO) pathway of arachidonic acid plays an important role in angiotensin II (AII)-mediated aldosterone synthesis. Several distinct isoforms of 12-LO have been cloned. However, in humans only the platelet form of 12-LO has been reported to be present. Western immunoblotting analysis in cultured human adrenal glomerulosa cells using polyclonal antibodies to porcine leukocyte 12-LO enzyme or peptide showed a specific 72-kilodalton band, which is identical to the molecular size of the porcine leukocyte form of 12-LO. In addition, AII (10(-7)) increased the intensity of the 72-kilodalton band nearly 2-fold over basal. In situ hybridization analysis indicated a strong positive reaction with the porcine leukocyte type of 12-LO antisense riboprobe in the zona glomerulosa of the adrenal cortex. The 12-LO probe also recognized a near 4-kilobase messenger RNA (mRNA) from human glomerulosa cells in Northern blots. Since the leukocyte type of 12-LO is highly homologous to human 15-LO, a reverse transcriptase and polymerase chain reaction was used to analyze the specific type of 12-LO mRNA in human cells. The mRNA for a porcine leukocyte type of 12-LO was detected in human adrenal glomerulosa cells, and the level of 12-LO transcripts was increased approximately 60-fold by AII (10(-7) M). The leukocyte type of 12-LO also was detected in human monocyte-like U937 cells, but not in IM-9 lymphocytes or human erythroleukemia cells. These results suggest that human adrenal glomerulosa cells and human monocyte-like U937 cells express a 12-LO which has immunological and molecular biological characteristics similar to the porcine leukocyte 12-LO.

Angiotensin II↗
PubMed1994

Metastatic meningioma to the second cervical vertebral body: a case report.

A rare case of C2 vertebral body metastasis from a parasagittal meningioma is reported. The metastatic lesion was found 13 years after resection of the primary lesion. The primary and the metastatic lesions had a similar and benign histological appearance. Remote metastasis of a meningioma can occur even with a benign histological finding after a variable disease-free period.

Adult↗
PubMed1994

Endoscopic resection of a subthalamic cavernous angioma: technical case report.

Endoscopic resection of a cavernous angioma at the subthalamic region was performed in a 33-year-old woman who presented with diplopia and progressive hemiparesis caused by recurrent hemorrhages. The entire surgical procedure was done through an 8-mm guiding tube inserted stereotactically from a frontal burr hole via an approach that traversed the anterior limb of the internal capsule. The patient's symptoms improved after surgery. This is believed to be the first report describing successful resection of a cavernous angioma located at the subthalamic region.

Adult↗
PubMed1994

Stereotactic gamma-thalamotomy with a computerized brain atlas: technical case report.

Radiosurgical stereotactic thalamotomy was performed in a patient with parkinsonian tremor with a computerized stereotactic brain atlas, which was transformed to fit the patient's thin-sliced magnetic resonance image to select an optimal target in the nucleus ventralis intermedius of the thalamus. The patient's tremor and rigidity disappeared and have not appeared again for more than 1 year since the eighth postoperative month. A method for converting the presurgically planned stereotactic coordinates in the atlas coordinate system to the coordinates in the frame coordinate system is described.

Aged↗
PubMed1994

Reduction of superoxide dismutase activity correlates with visualization of edema by T2-weighted MR imaging in focal ischemic rat brain.

This study investigated the correlation between in vivo serial T2-weighted magnetic resonance (MR) imaging and changes in superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities, and water, sodium ion (Na+), and potassium ion (K+) contents measured in vitro using rat brain following right middle cerebral artery occlusion in conjunction with bilateral common carotid artery (CCA) occlusion. One hour later the left CCA was released. Serial MR images showed edema developed from the outer cortex towards the center. The T2 signal intensity of the injured right cortex increased with time compared to that of the contralateral cortex. Increased Na+ and water and decreased K+ contents occurred in the injured cortex, indicating that serial T2-weighted MR imaging reflects the changes in water content and Na+ and K+ concentrations determined by biochemical techniques. GSH-Px activity was little changed. Total SOD in the injured cortex decreased 1 hour after ischemia and remained low throughout the experiment. In contrast, SOD activity in the noninfarcted left cortex also decreased after 1 hour but returned to normal after 2 hours of ischemia. Our results suggest that oxygen free radicals are important in developing ischemic brain edema and cerebral infarction.

Animals↗
PubMed1994

Posterolateral extradural approach for lateral thoracic meningocele--case report.

A 26-year-old female presented with a lateral thoracic meningocele associated with neurofibromatosis. The development of the thoracic meningocele was documented on serial chest roentgenograms. Magnetic resonance imaging and three-dimensional bone computed tomography scans were particularly useful to identify organic changes in the surrounding structures and the osseous orifice of the dural sac, respectively. The large thoracic meningocele was successfully treated through the posterolateral extradural approach in combination with resection of the adjacent ribs and cerebrospinal fluid drainage from the dural sac.

Adult↗
PubMed1994

Multiple cerebral aneurysms associated with aortitis syndrome--case report.

A 48-year-old female presented with four aneurysms in the anterior half of the circle of Willis associated with aortitis syndrome. All the aneurysms were successfully clipped. In general, intracranial hemodynamic change, due to stenosis or occlusion of carotid arteries, is considered to initiate aneurysm growth in the vertebrobasilar system in this syndrome, but renal hypertension was probably involved in our patient. Careful screening for multiple aneurysms, even in the anterior circulation, should be undertaken in patients with aortitis syndrome who present with an aneurysm.

Aortitis↗
PubMed1994

[A survey of the improvement of public transportation for the elderly. Reasons for giving up driving by retired automobile workers living in in Kanagawa Prefecture].

In order to improve the adequacy and safety of transportation for elderly people, the reasons for, and the after-effects of stopping driving by elderly people were analyzed. The subjects consisted of 500 car manufacturing retirees, aged 60 years old and over, living in Kanagawa prefecture. Of the 500 people questioned, 298 people (59.6%) responded. Of these 196 currently held licences. In this group, 149 still drove, 9 intended to stop driving soon, and 38 had already stopped. Of the 38 people who had already stopped driving, 7 quit before age 55. These people were omitted from analysis because factors other than aging possibly contributing to their stopping driving. We were interested in the 31 people older than 55 and the 9 people who intended to quit soon. The results were the following: I) The main reasons why they had stopped driving were the following: a) anxiety felt because of decreased driving ability and the feeling to need to walk in order to improve their health; b) the needlessness of driving because of availability of other means of transportation; II) The anxiety from decreased driving ability correlated with difficulty with narrow roads and imparied vision making it difficult to observed road signs; III) The reasons for stopping driving correlated with the effects: the needlessness of driving because of use of other means of transportation correlated with decreased frequency of going out for hobby and group activities. These results show that stopping driving also affects the social activities of the Japanese elderly. It was concluded that we should inform the elderly drivers of the effects of stopping driving as well as improving conditions on roads and comfort in automobiles.

Aged↗
PubMed1994

Direct clipping of basilar trunk aneurysms using temporary balloon occlusion.

In the surgical treatment of basilar trunk aneurysms, there is still considerable technical difficulty in gaining both proximal artery control and a sufficient operative field. The authors describe their experience in five patients with basilar trunk aneurysms treated using temporary balloon occlusion and intraoperative digital subtraction angiography. With the patient under general anesthesia, a heparinized angiography catheter was guided into the dominant vertebral artery by means of the Seldinger technique. A silicone balloon catheter was introduced coaxially through the angiography catheter to the basilar artery just proximal to the aneurysm. The balloon was inflated tentatively to evaluate the appropriate inflation volume, then the balloon catheter was withdrawn back into the angiography catheter to prevent thrombus formation. After exposure of the aneurysm, the occlusion balloon was advanced again and inflated temporarily within the basilar artery to prevent premature rupture and to facilitate dissection of the aneurysm. The mean duration of temporary balloon occlusion was 22 minutes. There were no patients with postoperative deficits attributable to the temporary occlusion. The results of aneurysm clip placement were confirmed by intraoperative digital subtraction angiography immediately after clipping. No patient suffered from distal embolism or other complications related to vessel catheterization. From this experience, it is concluded that this intraoperative endovascular technique can contribute to the success of surgery for complex cerebral aneurysms, particularly for basilar trunk aneurysms in which proximal vascular control is difficult.

Adult↗
PubMed1994

Induction of 12-lipoxygenase expression by epidermal growth factor is mediated by protein kinase C in A431 cells.

Epidermal growth factor (EGF) increases 12-lipoxygenase mRNA by about 2-fold with a lag period of 4 to 8 hr, which precedes the increase in 12-lipoxygenase activity by 2 to 4 hr in human epidermoid carcinoma A431 cells. Induction of 12-lipoxygenase expression in human erythroleukemia cells by phorbol 12-myristate 13-acetate (PMA) has been reported previously. The present report describes a study of the involvement of protein kinase C (PKC) in EGF-induced 12-lipoxygenase expression in A431 cells. EGF-induced 12-lipoxygenase expression was inhibited by methyl 2,5-dihydroxycinnamate, a tyrosine kinase inhibitor. Staurosporine and calphostin C, which are two PKC inhibitors, inhibited EGF-induced enzyme activity and mRNA expression of 12-lipoxygenase. 1,2-Dioctanoyl-sn-glycerol (a membrane-permeant diacylglycerol) and PMA significantly induced enzyme activity and mRNA expression. Simultaneous treatment of cells with EGF and PMA did not exhibit an additive effect, suggesting that EGF and PMA share a common biochemical pathway in 12-lipoxygenase induction. Expression of mRNA for PKC alpha, delta and zeta was detected in A431 cells, whereas no mRNA expression for PKC beta 1, gamma and epsilon was observed. Taken together, these results suggest that EGF-induced 12-lipoxygenase expression is at least in part mediated by the PKC signal transduction pathway.

Alkaloids↗
PubMed1994

[Development of the brainstem and cerebellum in autistic children].

Studies of magnetic resonance images have revealed morphological disorders of the brainstem and cerebellum in autistic children and adults. When we studied development of the brainstem and cerebellum in autistic patients, these structures were significantly smaller in autistic patients than in controls. Although the brainstem and cerebellum significantly increased in size with age in both groups, the development of the pons, cerebellar vermis I-V and cerebellar vermis VI-VII was significantly more rapid in autistic patients than in controls. However, the development of the other brain structures in the posterior fossa did not differ between autistic patients and controls. The regression intercepts of the brainstem and cerebellum as well as those of their components were significantly smaller in autistic patients than in controls. These results suggested that significant anatomical changes took place in the posterior fossa brain structures in the prenatal period in autistic children, but were not progressive.

Adolescent↗