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T Nakada

Publications and source records attributed to T Nakada.

At least 487 records · Page 27Linked to original sources
PubMed1987

Noninvasive evaluation of effects of an aldose reductase inhibitor in rat brain by 19F FDG NMR spectroscopy.

The inhibitory effects of an aldose reductase inhibitor, sorbinil (Pfizer, NY), on cerebral glucose metabolism were investigated noninvasively in rat brain using 19F nuclear magnetic resonance (NMR) spectroscopy and 2-fluoro-2-deoxy-D-glucose (2-FDG). Sorbinil given orally in the daily recommended doses (25 mg/kg) for man for the treatment of diabetic complications inhibited 2-FDG flux into the aldose reductase sorbitol (ARS) pathway, demonstrated as a reduction in the intensity of the ARS index resonance as well as an increase in the resonance area ratio between the pentose monophosphate shunt (PMS) and ARS index resonances (PMS/ARS ratio). Spatial metabolite mapping using rotating frame one-dimensional zeugmatography indicated that the inhibitory effect is spatially nonspecific. The present study is the first direct noninvasive observation of the effects of a pharmacological agent on cerebral enzymatic activities.

Aldehyde Reductase↗
PubMed1987

31P NMR spectroscopy of the stomach by zig-zag coil.

Phosphorus-31 (31P) nuclear magnetic resonance (NMR) spectroscopic investigations of the rat stomach were performed utilizing a 1-cm2, three-turn, zig-zag coil. A zig-zag coil of this dimension produced an effective B1 field that extends only within a 4-mm distance from the plane of the surface coil, rendering it possible to obtain high-resolution 31P spectra localized to the stomach without contamination from surrounding tissues. Normal stomach showed a characteristic spectral pattern with resonances reflecting inorganic phosphate (Pi), phosphocreatine (PCr), and the alpha-, beta-, and gamma-phosphates of adenosine triphosphate (ATP). Ischemia-induced changes in Pi, PCr, and ATP resonances were readily followed in vivo with a time resolution of 2.13 min. Indomethacin-induced ulcer revealed a low intracellular pH and a decrease in the PCr to Pi ratio indicating the partially ischemic conditions of ulcerative lesions of the stomach as has been previously suggested. The present studies indicate that 31P NMR spectroscopy utilizing a zig-zag coil is a powerful tool to study local pathology of the gastrointestinal (GI) tract. Since zig-zag coils suitable for fiberscopic devices are easily constructed, clinical applications of the present technique are apparent.

Animals↗
PubMed1987

Limbic lymphoma.

Two cases of metastatic malignant lymphoma confined to the limbic-hypothalamic region are presented. The non-specific nature of the neurological symptoms associated with these lesions such as memory loss, impotence and confusion made neurological localization of the disease process difficult. While non-contrast computed tomography (CT) was unremarkable, contrast CT was diagnostic, showing bilateral homogenous enhancement of specific limbic-hypothalamic structures without significant mass effect. Since lymphomatous involvement of the limbic-hypothalamic area tends to be infiltrative without attendant mass effect, detection of metastasis may be elusive unless special attention is directed to this region. As lymphoma is often chemoresponsive and highly radiosensitive, early recognition of limbic-hypothalamic involvement of this disease is important.

Hodgkin Disease↗
PubMed1987

Clinical analysis of ureteral tumours with or without renal pelvic neoplasms.

Twelve patients with ureteral tumours with or without ipsilateral renal pelvic neoplasms were retrospectively analysed. Haematuria was the most common symptom. Location of all tumours was preoperatively detected by conventional diagnostic methods, such as intravenous or retrograde pyelography, washing cytology of the upper urinary tract, computed tomography, echogram and abdominal aortography. Cumulative proportion survivals of 1, 3 and 5 years were 81.9%, 68.2% and 45.5%, respectively. Patients with high Karnovsky rating survived longer (p less than 0.05) than those with low rating. Patients with low-stage tumours (T1, T2) showed longer survival rate (p less than 0.001) than those with high-stage tumours (T3, T4). Vascular invasion of tumour cells was present in removed specimens in 4 out of 7 patients who died or are alive with cancer, but none in those who survived without disease. Good therapeutic response could not be achieved unless surgery was performed.

Aged↗
PubMed1987

Sensory and cognitive evoked potentials in a case of congenital hydrocephalus.

We studied auditory and visual evoked potentials in D.W., a patient with congenital stenosis of the cerebral aqueduct. Head CT scans revealed marked hydrocephalus with expanded ventricles filling more than 80% of the cranium and compressing brain tissue to less than 1 cm in thickness. Despite the striking neuroanatomical abnormalities, however, the patient functioned well in daily life and was attending a local community college at the time of testing. Evoked potentials provided evidence of preserved sensory processing at cortical levels. Pattern reversal visual evoked potentials had normal latencies and amplitudes. Brain-stem auditory evoked potentials (BAEPs) showed normal wave V latencies. Na and Pa components of middle-latency AEP had normal amplitudes and latencies at the vertex, although amplitudes at lateral electrodes were larger than at the midline. In contrast to the normal sensory responses, long-latency auditory evoked potentials to standard and target tones showed abnormal P3 components. Standard tones (probability 85%), evoked N1 components with normal amplitudes (-3.7 microV) and latencies (103 msec), but also elicited large P3 components (17 microV, latency 305 msec) that were never observed following frequent stimuli in control subjects. Target stimuli (probability 15%) elicited P3s in D.W. and controls, but P3 amplitudes were enhanced in D.W. (to more than 40 microV) and the P3 showed an unusual, frontal distribution. The results are consistent with a subcortical source of the P300. Moreover, they suggest that the substitution of controlled for automatic processes may help high-functioning hydrocephalics compensate for abnormalities in cerebral structure.

Adult↗
PubMed1987

Heterogeneity of regional cerebral glucose metabolism demonstrated in situ in rat brain by 19F NMR rotating frame zeugmatography: one dimensional chemical shift imaging of normal and gliosarcoma implanted brain.

Using 19-fluorine (19F) as nuclear magnetic resonance (NMR) signal probe and 2-fluoro-2-deoxy-D-glucose (2-FDG) as metabolic probe, one dimensional "imaging" (metabolite mapping) of pathway specific glucose metabolism in the pentose monophosphate shunt (PMS) and aldose reductase sorbitol (ARS) pathways were performed in situ in rat brain utilizing one dimensional rotating frame zeugmatography. Normal brain showed highest PMS activities in the brainstem consonant with known spatially heterogeneous concentration of glucose-6-phosphate dehydrogenase, the rate limiting enzyme for the PMS. The brain harboring sufficiently large gliosarcoma in the cerebrum showed a higher PMS/ARS area ratio indicating higher PMS activities in tumor which was localized by zeugmatography. The present study demonstrated the feasibility of studying regional glucose metabolism in the PMS and ARS utilizing 2-FDG.

Aldehyde Reductase↗
PubMed1987

Low level of superoxide dismutase activity in pheochromocytoma.

A copper-zinc superoxide dismutase found in the cytosol and intermembrane space of mitochondria, and a manganese superoxide dismutase detected in the mitochondria were determined in pheochromocytomas and normal adrenal tissues. Manganese superoxide dismutase activity in pheochromocytomas was lower than that in the normal adrenal tissues but copper-zinc superoxide dismutase activity was almost identical. The total catecholamine content in pheochromocytomas was greater than that in the normal adrenal tissues, and negative relationships were noted between superoxide dismutase activities and total catecholamine content in pheochromocytomas alone. The low level of manganese superoxide dismutase activity might be a characteristic of pheochromocytomas and the decrease in manganese superoxide dismutase activity may not be attributed solely to a decrease in the amount of mitochondria but to a nonspecific abnormality in mitochondrial enzymes.

Adrenal Gland Neoplasms↗
PubMed1987

Liddle's syndrome, an uncommon form of hyporeninemic hypoaldosteronism: functional and histopathological studies.

Liddle's syndrome was diagnosed in a 72-year-old man who presented clinically with hypertension and muscle weakness. This disorder has been characterized by hyporeninemic hypoaldosteronism, hypertension, hypokalemia and enhanced erythrocyte sodium influx. Administration of spironolactone failed to correct the hypertension and electrolyte abnormality, which subsequently improved with triamterene therapy and a low salt diet. However, suppression of the renin-angiotensin-aldosterone system remained unchanged after this treatment. In addition, an atrophic juxtaglomerular apparatus and hypertensive lesions in the arterioles were confirmed by kidney biopsy after triamterene therapy. Therefore, a process of intrinsic hyperactive distal sodium reabsorption, probably affected by aldosterone-independent sodium transport into erythrocytes, appears to be important in the pathogenesis of this syndrome. Triamterene therapy, which usually is performed in patients with this disease, might not be the ultimate therapy in the future even if electrolyte abnormalities were to be improved temporarily.

Aged↗
PubMed1987

Noninvasive demonstration of in vivo 3-fluoro-3-deoxy-D-glucose metabolism in rat brain by 19F nuclear magnetic resonance spectroscopy: suitable probe for monitoring cerebral aldose reductase activities.

The metabolism of 3-fluoro-3-deoxy-D-glucose (3-FDG) in rat brain in vivo was investigated noninvasively using 19F nuclear magnetic resonance (NMR) spectroscopy. Following an intravenous infusion of 3-FDG, 400 mg/kg, four resonances assigned to the alpha and beta anomers of 3-FDG, 3-fluoro-3-deoxy-D-sorbitol, and 3-fluoro-3-deoxy-D-fructose were clearly resolved in brain, a result indicating that 3-FDG is metabolized primarily into the aldose reductase sorbitol (ARS) pathway. An orally administered aldose reductase inhibitor, sorbinil, caused reduction of the flux of 3-FDG into the ARS, an observation suggesting that the method can be applied in quantitative studies of ARS pathway activities. Studies of 24-h urine specimens showed that in addition to the two metabolites observed in brain, F- was excreted into the urine. 3-FDG appears to be a suitable metabolic probe for assessing glucose metabolism in the ARS pathway by in vivo 19F NMR spectroscopy.

Aldehyde Reductase↗
PubMed1987

Evidence for a defect in urinary concentrating ability in primary aldosteronism and its reversal by adrenal surgery.

Of 15 patients with primary aldosteronism, 7 had idiopathic adrenal hyperplasia (IHA) and 8 had aldosterone-producing adenoma (APA). In order to determine any renal problems involved in the treatment, the renal clearance of these patients was analyzed and the results compared with those obtained from 12 patients with essential hypertension. With water diuresis or under antidiuresis status, levels of urine volume, Cosm and CH2O in patients with APA were greater (p less than 0.05-p less than 0.001) than those of patients with essential hypertension, while the fractional tubular sodium delivery of the former patients was lower than that of the latter patients (p less than 0.001 or less than 0.05). A similar tendency was observed in clearance studies in patients with IHA, although to a lesser extent. Adrenal surgery for patients with APA normalized these values, but administration of trilostane (3 beta-hydrosteroid dehydrogenase inhibitor) to patients with IHA failed to improve these values. These results indicate that impaired urinary concentrating ability as well as reduced urinary diluting capability is a common feature of primary aldosteronism. Such impaired renal function was improved only in patients with APA after adrenal surgery.

Adenoma↗
PubMed1987

Use of indwelling double-curved ureteral stents and problems after stenting.

Indwelling double-curved ureteral stents were placed in 19 patients for 28 months. We used these stents to bypass ureteral obstruction and as adjunct surgery of upper urinary tract troubles. There were 5 cases with stent problems such as stone formation and spontaneous breakage. The duration of stenting with problems was longer than that without problems with statistical significance.

Adult↗
PubMed1987

Detection of early lung cancer: results of radiologic and cytologic screening in the Miyagi program.

Eighty-eight lung cancers including 82 primary and 6 metastatic tumors were detected by chest X-ray examination of a total of 363,320 participants in Miyagi Prefecture in Japan during 3 years period from 1982 to 1984. Sputum cytology was performed in the high-risk group (above 50 years of age with cigarette index above 600) of the total participants during the same period. This detected 67 patients with malignant tumors including 5 with cancer of the upper respiratory tract and 62 with primary lung cancer. Fifty-one of 67 cancers (82.3%) detected by sputum cytology were radiographically occult lung cancers. The annual ratio of the detection of lung cancer was 45/100,000 in the first year, however, it decreased to 38/100,000 in the second year and to 15/100,000 in the third year. Cancer resection was performed in 63.6%, 76.1% and 80.0% of the patients, in the first, the second and the third year, respectively. On the average, 57% of the patients who underwent cancer resection demonstrated early lung cancer. Especially, 45 of 51 patients with lung cancer detected by sputum cytology underwent tumor resection, of which 40 (89%) bore early lung cancer.

Adenocarcinoma↗
PubMed1987

Histologic assessment of bronchial anastomotic healing in canine lung transplantation.

Postoperative wound healing of the bronchial anastomosis was studied in dogs with autotransplantation (20 dogs, 7 days to 6 years postoperatively) and allotransplantation (62 dogs, 5 to 174 days postoperatively) of the left lung. In the group undergoing lung allotransplantation, the relationship among three histologic parameters was studied: the grade of lung allograft rejection, the degree of changes in the epithelium, and submucous lymphocyte infiltration along the donor bronchus within approximately a 0.5 cm area distal to the anastomosis. In lung autotransplantation, mucosal continuity began to be observed 1 week postoperatively. Mucosal continuity and apparent collagen formation on any bronchial contiguous site were demonstrated in most animals studied more than 3 weeks postoperatively. Bronchial anastomotic healing tended to be slower in lung allotransplantation than in autotransplantation, although a mucosal continuity at the anastomosis was sporadically observed in immunosuppressed dogs surviving more than 3 weeks postoperatively with a lung allograft. There were significant rank correlations among the three histologic parameters, which showed that lung allograft rejection is closely connected with wound healing of the bronchial anastomosis in lung allotransplantation. Meticulous mucosal approximation is most necessary during bronchial anastomotic procedures. Establishment of an exact method for early monitoring of lung allograft rejection is absolutely necessary for lung allotransplantation.

Animals↗