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Biomedical subjects

T Morioka

Publications and source records attributed to T Morioka.

At least 19 recordsLinked to original sources
PubMed1995

Bidirectional effects of aminophylline on myocardial ischemia.

BACKGROUND: Aminophylline blocks adenosine receptors and increases levels of plasma catecholamines. We investigated the effect of aminophylline on myocardial ischemia by varying its severity and attempted to identify the mechanism by which aminophylline modulates myocardial ischemia in the canine model. METHODS AND RESULTS: In 41 open-chest dogs, the left anterior descending coronary artery was cannulated and perfused with blood through a bypass tube from the left carotid artery. When coronary blood flow (CBF) was reduced to 80% of the control, aminophylline increased fractional shortening (FS) from 11.0 +/- 0.4% to 18.5 +/- 1.7% (P < .05) and lactate extraction ratio (LER) from 7.5 +/- 0.1% to 13.6 +/- 1.0% (P < .01). The endocardial to epicardial flow ratio (Endo/Epi ratio) of regional myocardium was also increased. Release of adenosine was increased compared with the nonischemic condition (7 +/- 3 versus 28 +/- 5 pmol/mL). Prazosin, an alpha 1-adrenoceptor antagonist, blunted the aminophylline-induced improvement in contractile and metabolic function. Administration of 8-phenyltheophylline, a selective antagonist of adenosine receptors, did not increase FS, LER, or the Endo/Epi ratio when CBF was reduced to 80% of control. When CBF was reduced to 60% of control, aminophylline did not change the metabolic and contractile function. In contrast, when CBF was reduced to 33% of control, release of adenosine was increased markedly (243 +/- 19 pmol/mL) and aminophylline induced decreases in FS, LER, and Endo/Epi ratio similar to those observed with 8-phenyltheophylline. CONCLUSIONS: Aminophylline had opposite effects on the ischemic myocardium depending on the severity of ischemia. It improved mild ischemia but worsened severe ischemia. The beneficial effect of aminophylline was attributable to alpha 1-adrenoceptor stimulation, which improves endomyocardial flow in the ischemic myocardium. The deleterious effect was attributable to the aminophylline-induced blockade of adenosine receptors.

Adenosine↗
PubMed1995

Alpha 1-adrenoceptor activation increases ecto-5'-nucleotidase activity and adenosine release in rat cardiomyocytes by activating protein kinase C.

BACKGROUND: Adenosine is an important regulator of many cardiac functions and is synthesized primarily by ecto- and cytosolic 5'-nucleotidase. We have previously reported that alpha 1-adrenoceptor blockade attenuates adenosine release from ischemic myocardium, raising the possibility that alpha 1-adrenoceptor activation activates 5'-nucleotidase. This study tested whether activation of protein kinase C by alpha 1-adrenoceptor activation increases 5'-nucleotidase activity and augments adenosine release. METHODS AND RESULTS: Cardiomyocytes were isolated from adult male Wistar rats and suspended in modified HEPES-Tyrode's buffer solution. After stabilization, the cardiomyocytes were incubated with and without an exposure to norepinephrine (10(-9) to 10(-5) mol/L) while being treated with propranolol and yohimbine or with and without an exposure to methoxamine (10(-9) to 10(-5) mol/L). Ecto-5'-nucleotidase activity was increased by norepinephrine and methoxamine during 30 minutes in a dose-dependent manner, whereas cytosolic 5'-nucleotidase was not activated. These increases in ecto-5'-nucleotidase activity were inhibited by GF109203X, an inhibitor of protein kinase C, and mimicked by phorbol 12-myristate 13-acetate (PMA), an activator of protein kinase C. The increase in ecto-5'-nucleotidase was not prevented by cycloheximide. When ecto-5'-nucleotidase activity increased, adenosine release was augmented in methoxamine- and PMA-treated cardiomyocytes (1299 +/- 252% and 1372 +/- 149%, respectively) compared with the untreated group (578 +/- 26%). The increase in adenosine release was blunted by GF109203X and alpha, beta-methyleneadenosine 5'-diphosphate, an inhibitor of ecto-5'-nucleotidase. CONCLUSIONS: Thus, we conclude that alpha 1-adrenoceptor-mediated increases in ecto-5'-nucleotidase activity are attributed to activation of protein kinase C in rat cardiomyocytes.

5'-Nucleotidase↗
PubMed1995

Cranial fasciitis with massive intracranial extension.

The case of a 10-month-old boy with cranial fasciitis is described. The patient had a rapidly growing subcutaneous mass in the left frontotemporal region. Computed tomography and magnetic resonance imaging clearly demonstrated a mass in the left temporoparietal bone extending both intra- and extracranially. The tumor seemed to originate from the calvarium, being located between the periosteum and the dura mater. Total resection of the tumor was performed, and the tumor was histologically identified as cranial fasciitis. A brief review of the literature is included that emphasizes the need for further investigation of this benign lesion that is frequently confused with a malignant neoplasm.

Brain Diseases↗
PubMed1995

Pharmacokinetic study of valproic acid sustained-release preparation in patients undergoing brain surgery.

Pharmacokinetics of valproic acid sustained-release preparation (VPA-SR) were studied in nine patients undergoing surgery for brain tumor. Total (t) and free (f) serum concentrations were analyzed in samples drawn during the day of brain surgery and compared with levels from a postoperative day. The area under the curve (AUCt) and clearance (CLt) of the total concentration did not differ on these occasions. In contrast, statistically significant differences were observed in AUCf and CLf between the two occasions; increased AUCf and decreased CLf were observed on the day of surgery. A significant relation was found between the average free fraction (AUCf/AUCt on operation day per AUCf/AUCt on postoperative day) and estimated blood loss during operation (r = 0.82; p < 0.001). In addition, a significant relation was found between simple free fraction and the intraoperative albumin level in serum (r = -0.68; p < 0.001). These findings indicate that the increased VPA free concentration is due to low serum albumin level secondary to blood loss and that there has been a decrease in intrinsic clearance during operation.

Adolescent↗
PubMed1995

Progressive renal lesions induced by administration of monoclonal antibody 1-22-3 to unilaterally nephrectomized rats.

A new animal model of progressive glomerulosclerosis was developed by administering a single i.v., injection of MoAb 1-22-3 to unilaterally nephrectomized rats. Renal morphological analysis revealed that glomerular lesions characterized by mesangial cell proliferation and mesangial matrix expansion were induced in about 95% of the glomeruli. Approximately 20% of the glomeruli of the unilaterally nephrectomized rats showed sclerosis or segmental sclerosis by week 6 after MoAb injection and crescent formation was observed in some glomeruli (ca 4%). Cellular infiltration was also noted in some parts of the interstitium. Increased expression of transforming growth factor-beta (TGF-beta) was observed in the unilaterally nephrectomized rats treated with MoAb 1-22-3, but we could not demonstrate pathological involvement of platelet-derived growth factor (PDGF), even though early-stage mesangial cell proliferation was observed. The mechanism of mesangial cell proliferation in this model remains to be elucidated. The relatively short period of time needed to induce the sclerotic changes in considered to be a great advantage of this model for clarifying the mechanisms involved in the chronic progression of mesangial proliferative glomerulonephritis.

Animals↗
PubMed1995

Downward shift of coronary pressure-flow relationship following a brief period of ischemia in dogs.

This study was undertaken to test whether a brief period of ischemia affects the coronary pressure-flow relationship during reduction of coronary perfusion pressure (CPP). The left anterior descending coronary artery was cannulated and perfused with blood from the left carotid artery in 40 open-chest dogs. Coronary blood flow (CBF) was measured during intracoronary administrations of papaverine and adenosine. The coronary pressure-flow relationship was assessed during transient reduction of CPP from 100 to 30 mmHg. Coronary hyperemic flow due to adenosine and papaverine was attenuated 30 min after transient 10- and 15-min periods of ischemia. In the group of transient 10-min ischemia, both fractional shortening (FS) and CBF returned to the preischemic values at 30 and 60 min of reperfusion; however, marked decreases in CBF (35 +/- 5 vs. 56 +/- 4 ml.100 g-1.min-1 at CPP = 60 mmHg, P < 0.01) during graded reductions in CPP were observed. The endomyocardial blood flow was reduced relative to the control condition. Furthermore, both FS (6 +/- 1 vs. 14 +/- 1% at CPP = 60 mmHg, P < 0.01) and lactate extraction ratio (-41 +/- 15 vs. 1 +/- 6% at CPP = 60 mmHg, P < 0.05) were decreased. The downward shift of the CPP-CBF relationship and the deterioration of myocardial contractile and metabolic function during reduction of CPP were restored 60 min after the onset of reperfusion.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine↗
PubMed1995

Primary intracranial squamous cell carcinomas: report of two cases.

Two cases of primary intracranial squamous cell carcinomas are reported. The first patient is a 57-year-old man with an epidermoid carcinoma in the right cerebellopontine angle, having histological features that indicated malignant transformation in a benign epidermoid cyst. The second patient is a 42-year-old man in whom squamous cell carcinoma arose in a pre-existing middle fossa dermoid cyst 9 years after the initial surgical resection. The literature on primary intracranial squamous cell carcinomas is reviewed, and the clinical features and histological pathogenesis for the occurrence of this unique condition are discussed.

Adult↗
PubMed1995

Acquired Chiari I malformation and syringomyelia associated with bilateral chronic subdural hematoma. Case report.

The authors report a case of bilateral chronic subdural hematoma in a 25-year-old woman who had occipital and neck pain. Magnetic resonance imaging revealed progressive caudal descent of the cerebellar tonsils (acquired Chiari I malformation) and a large eccentric syrinx in the spinal cord from the C3-T7 levels. Spontaneous disappearance of the chronic subdural hematomas resulted in radiographic resolution of both lesions, as well as clinical improvement. Theories of syringomyelia formation, the relationship to acquired Chiari I malformation, and the implications of this case are discussed.

Adult↗
PubMed1994

Kinetics of macrophage subpopulations and expression of monocyte chemoattractant protein-1 (MCP-1) in bleomycin-induced lung injury of rats studied by a novel monoclonal antibody against rat MCP-1.

We investigated the kinetics of macrophage subpopulations and the expression of monocyte chemoattractant protein 1 (MCP-1) in a rat model of bleomycin-induced lung injury. Rat macrophage subpopulations were examined by immunohistochemistry using various anti-rat macrophage monoclonal antibodies (mAbs) and their proliferative capacity by [3H]thymidine (3HTdR) autoradiography. To detect the localization of expressed MCP-1, we generated an mAb against rat MCP-1 for immunohistochemical staining. Expression of MCP-1 messenger RNA (mRNA) was detected by Northern blot hybridization. Shortly after intratracheal instillation of bleomycin, the number of exudate macrophages recognized by mAb TRPM-3 increased in the injured lungs, peaked 3 days later, and decreased thereafter, whereas tissue macrophages identified by mAb ED2 increased slowly and peaked 2 weeks after instillation. Northern blot analysis disclosed that the expression of MCP-1 mRNA in the lung was most prominent 1 day after instillation and declined thereafter, preceding the numerical change of the TRPM-3-positive exudate macrophages. Immunohistochemistry with anti-rat MCP-1 revealed that the main sources of MCP-1 production were alveolar and interstitial macrophages and polymorphonuclear leukocytes. Based on these results, MCP-1 produced by polymorphonuclear leukocytes and by alveolar and interstitial macrophages is thought to induce the infiltration of blood monocytes, and infiltrated exudate macrophages produce MCP-1 to enhance subsequent accumulation of macrophages. In contrast, the expression of MCP-1 did not correlate with the numerical changes of the ED2-positive macrophages.

Animals↗
PubMed1994

Selective planting of cationized, haptenized ovalbumin on the rat tubular basement membrane.

We developed an experimental protocol for planting exogenous antigens with different molecular weights and charges on the constituents of the renal tubulointerstitium. The cationized antigens were injected selectively into the left renal arteries of Wistar rats. Antigen localization was documented by immunohistochemistry on frozen sections. Cationized bovine serum albumin (BSA; 68 kDa, isoelectric point = 9.5) localized almost exclusively along the glomerular capillary wall. After application of highly cationic polyethyleneimine, cationized BSA given subsequently was found in a linear distribution along the glomerular capillary wall and along the peritubular capillaries. The fate of highly cationized ovalbumin conjugated with trinitrophenol (TNP-OA), subjected to gel filtration to obtain monomers (42 kDa, isoelectric point > 10) differed; it was deposited in a linear pattern on the tubular basement membrane (TBM) and Bowman's capsule, and remained up to 36 h after injection. Noncationized, monomeric TNP-OA (42 kDa, isolectnic point = 4.6) showed fine granular deposition in the tubular epithelium exclusively. These findings indicate that the barrier of the glomerular BM acts selectively on antigens with different molecular weights. They either settle on the peritubular capillaries, after passing the glomerular, or reach the urinary space, after which they are reabsorbed by the tubular epithelial cells to reach the TBM.

Animals↗
PubMed1994

Malignant lymphoma of the scalp at the site of a previous blunt trauma: report of two cases.

We describe two cases with malignant lymphoma presented as scalp tumors. Both patients had slowly growing subcutaneous lymphoma masses in the scalp after head trauma. In the first case, the scalp lymphoma presented as a recurrent disease during complete remission of her systemic lymphoma after chemotherapy. In the second case, the tumor involved the scalp, subjacent skull, and intracranial space without systemic manifestation. These cases represent examples of a possible relationship between head trauma and the development of between head trauma and the development of tumors involving the brain and its coverings.

Aged↗
PubMed1994

Choroidal fissure cyst in the temporal horn associated with complex partial seizure.

We describe two cases presenting with small cysts in the choroidal fissure of the temporal horn (choroidal fissure cyst). Both patients manifested solely complex partial seizure. On magnetic resonance imaging, the signal intensity of the cyst was identical to that of the cerebrospinal fluid, and the underlying hippocampus was compressed by the cyst. Since the cyst was thought to be of a neuroepithelial type, and therefore of benign nature, surgical intervention was avoided since satisfactory medical control of the seizures was obtained.

Adult↗
PubMed1994

Histone mediates glomerular deposition of small size DNA anti-DNA complex.

Histone can mediate the binding of free DNA to the glomerular capillary wall. We tested whether histone could mediate the deposition of preformed DNA-anti-DNA immune complex (IC). IC were generated using monoclonal anti-DNA Ab and excess of small size 125I-DNA; after further digestion with DNase the IC, containing 5 micrograms DNA (now 20 to 60 bp), was injected into the left kidney of rats. When given alone, only about 0.2% of the IC bound in glomeruli. Prior injection of 200 micrograms of core histones (H2A,H2B,H3,H4) resulted in high glomerular binding of the IC; 18.1% of the injected dose (measured as 125I-DNA) was bound at 15 minutes. Mouse immunoglobulin, representing the IC, could be seen in a capillary pattern. C3 was also present in a similar pattern, showing that complement had been activated. Discrete electron-dense deposits were seen in a subendothelial and subepithelial localization at 15 minutes. Although about 1 microgram of DNA was deposited in the glomeruli, it could not be detected by indirect immunofluorescence or intercalating dyes. These studies provide direct evidence that histones can mediate the binding of particular circulating DNA-anti-DNA immune complexes to the glomerular capillary wall in vivo. If small size DNA fragments (< 100 bp) are involved in lupus nephritis, our results provide a possible explanation for the frequent failure to detect DNA deposits in renal biopsies from SLE patients.

Animals↗
PubMed1994

Microcystic meningioma: clinicopathological features of 6 cases.

The clinical and morphological features of 6 patients with unusual meningiomas with extensive microcystic formation are presented. There were 4 males and 2 females, ranging in age from 30 to 64 years. The clinical and neuro-imaging features of these tumours were identical with those of meningiomas in general. Morphological examinations disclosed that the tumour cells in 4 cases had many ultrastructural characteristics in common with the arachnoid cap cells, viz. prominent and complex interdigitation of the fine cytoplasmic processes, many desmosomes, and intracytoplasmic microfilaments. In contrast, the tumour cells of 2 cases had characteristic structures in common with trabecular arachnoid cells, viz. stellate in shape, a small number of intracytoplasmic filaments, relatively thick cytoplasmic processes, and occasional desmosomes. The tumour cells in these 2 cases were considered to recapitulate the subarachnoid structure and showed microcystic appearance. Although the histogenesis of microcysts in meningiomas is considered not to be uniform, the biological behaviour of these 6 tumours corresponded to those of meningiomas in general.

Adult↗
PubMed1994

AICA riboside improves myocardial ischemia in coronary microembolization in dogs.

This study was undertaken to examine whether 5-amino-4-imidazolecarboxamide (AICA) riboside (acadesine), which augments adenosine release in ischemic myocardium, further attenuates ischemic injury after acute coronary microembolization. The left anterior descending coronary artery was cannulated and perfused with blood from the left carotid artery in 46 dogs, and coronary blood flow (CBF) of the perfused area was measured. In 12 dogs, 15-microns microspheres (5.0 x 10(4)/ml) were injected repeatedly until CBF approached zero. Changes in CBF, fractional shortening, lactate extraction ratio, and adenosine release were measured with and without administration of AICA riboside. In the control group (n = 7), CBF increased to 154 +/- 11 ml.100 g-1.min-1 at 16-30% of total coronary embolization, and adenosine release was 6.1 +/- 1.0 nmol.100 g-1.min-1. Administration of AICA riboside (n = 5) enhanced coronary hyperemia (187 +/- 8 ml.100 g-1.min-1, P < 0.05), adenosine release (11.9 +/- 0.9 nmol.100 g-1.min-1, P < 0.001), and myocardial adenosine content (0.434 +/- 0.069 vs. 0.118 +/- 0.019 nmol/mg wet wt, P < 0.01) and attenuated decreases in fractional shortening and lactate extraction ratio. AICA riboside preserved myocardial tissue ATP content of the embolized area. The administrations of 8-phenyltheophylline (n = 12) and alpha,beta-methyleneadenosine 5'-diphosphate (n = 10) abolished the beneficial effects of AICA riboside. Furthermore, AICA riboside increased ectosolic and cytosolic 5'-nucleotidase activity of the embolized myocardium (n = 12). Thus we conclude that AICA riboside attenuates contractile and metabolic dysfunction by enhancing adenosine release via activation of ectosolic 5'-nucleotidase and inducing local hyperemia in acute coronary microembolization.

5'-Nucleotidase↗
PubMed1994

Infarct size-limiting effect of ischemic preconditioning is blunted by inhibition of 5'-nucleotidase activity and attenuation of adenosine release.

BACKGROUND: We have previously reported that ischemic preconditioning increases 5'-nucleotidase activity and adenosine release during ischemia and reperfusion. However, its direct cause-and-effect relation has not been proven. To test the idea that the infarct size-limiting effect of ischemic preconditioning is blunted by inhibition of ectosolic 5'-nucleotidase activity, we assessed 5'-nucleotidase activity, adenosine release, and infarct size caused by sustained ischemia with and without an exposure to alpha,beta,-methylene adenosine 5'-diphosphate (AOPCP) in the ischemia-preconditioned myocardium. METHODS AND RESULTS: In 67 open-chest dogs, the left anterior descending coronary artery was cannulated and perfused with an extracorporeal bypass tube from the carotid artery. After hemodynamic stabilization, the coronary artery was occluded four times for 5 minutes separated by 5 minutes of reperfusion (ischemic preconditioning, n = 10). After this procedure, the coronary artery was occluded for 90 minutes followed by 6 hours of reperfusion. Infarct size normalized by the risk area was smaller than the control group (n = 8, 41.0 +/- 2.6% versus 6.8 +/- 1.9%), although there were no significant differences in the endomyocardial collateral flow measured at 80 minutes of ischemia (8.5 +/- 1.1 versus 9.4 +/- 1.0 mL/100 g per minute). Ectosolic and cytosolic 5'-nucleotidase activity and adenosine release were increased during reperfusion in the ischemic preconditioning group compared with the control group, and the activity of ectosolic 5'-nucleotidase was markedly reduced by AOPCP (n = 10). AOPCP affected neither adenosine-induced coronary vasodilation nor increases in myocardial oxygen consumption during an intracoronary infusion of isoproterenol (n = 10). To test whether the increase in 5'-nucleotidase activity decreases infarct size, we infused AOPCP 10 minutes before the ischemic preconditioning procedure and continued for 60 minutes after the onset of reperfusion (n = 8). AOPCP blunted the infarct size-limiting effect (infarct size, 38.8 +/- 4.9%). AOPCP without ischemic preconditioning did not increase infarct size (n = 9). Furthermore, when AOPCP was infused during the ischemic preconditioning procedure (n = 6) or during 60 minutes of reperfusion (n = 6), the infarct size-limiting effect was partially blunted (infarct size, 21.3 +/- 2.5% and 19.5 +/- 2.4%, respectively). CONCLUSIONS: Increases in ectosolic 5'-nucleotidase activity and adenosine release are primarily responsible for the infarct size-limiting effect of ischemic preconditioning. Exposures to adenosine during the ischemic preconditioning procedure and enhanced release of adenosine during reperfusion synergistically contribute to the infarct size-limiting effects.

5'-Nucleotidase↗