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Biomedical subjects

T Akiba

Publications and source records attributed to T Akiba.

At least 19 recordsLinked to original sources
PubMed1995

[Morphological study on the gastric mucosa in diabetes mellitus rats induced by streptozotocin].

To clarify the pathogenesis of vulnerability to acute gastric mucosal lesion (AGML) in diabetes mellitus (DM), we investigated histopathologically the gastric mucosa of the fundic gland in streptozotocin-induced DM rats. The length of the mucosa and the thickness of the surface epithelial cell (SEC) layer were measured, and the number of proliferating cell nuclear antigen (PCNA) positive cells was counted. As results, compared with control rats, the ratio of the length of SEC layer to that of mucosa, and the number of PCNA positive cells were significantly decreased in DM rats, whereas the length of the mucosa tended to extend in DM rats. Consequently, it is considered that attenuation of mucosal barrier in the SEC layer can be closely associated with susceptibility to occurrence of AGML in DM.

Animals↗
PubMed1995

[A case of pentalogy of Cantrell with tetralogy of Fallot and left ventricular diverticulum].

We report a successful repair of tetralogy of Fallot and left ventricular diverticulum associated with pentaology of Cantrell. The repair consisted of partial infundibular septectomy, closure of ventricular septum, reconstruction of right ventricular outlet using monocuspid transjunctional patch, and resection of left ventricular diverticulum. The infundibulum was extremely elongated, caused by ventricular dextroversion, and the hypoplasia of pulmonary trunk was absent. Therefore, transjunctional patch was longer, even after infundibular septectomy. This report discuss the pathogenesis of these cardiac anomalies and surgical imlication.

Abnormalities, Multiple↗
PubMed1995

Intravenous calcitriol can increase bone mass in hemodialysis patients with osteitis fibrosa.

Intravenous calcitriol administration (IVC) suppressed parathyroid hormone (PTH) secretion and improved osteitis fibrosa (OF) in long-term hemodialysis (HD) patients, although it did not increase the mineralized bone area or the mineral apposition rate. We observed the long-term effects of IVC on OF in 8 HD patients. Bone biopsy of 7 patients revealed increased bone turnover and decreased bone mass. One microgram of calcitriol was given intravenously three times weekly after each HD session for 12 months. The dose was adjusted to maintain the serum corrected calcium level at < 11.5 mg/dl. Dual-energy X-ray bone absorptiometry (DEXA), 3rd lumbar vertebra bone density by quantitative computed tomography (QCT), and biochemical data were taken before IVC, and after 6 and 12 months of IVC. Seven HD patients were given 0.5 microgram/day 1 alpha-cholecalcitriol as controls. The serum corrected calcium levels were 9.9 +/- 0.3 (mean +/- SE) and 11.1 +/- 0.2 mg/dl at 0 and 12 months, respectively (p = 0.06). The serum phosphate levels were 6.2 +/- 0.7 and 6.6 +/- 0.6 mg/day at 0 and 12 months, respectively (p = 0.56). The serum intact PTH levels were 928 +/- 281 and 617 +/- 192 (p = 0.016) at 0 and 12 months, respectively. The bone mass of the 3rd lumbar vertebra measured by QCT was 195 +/- 17 and 218 +/- 186 g/cm3 at 0 and 12 months, respectively (p = 0.156). The bone mass of the trunk measured by DEXA was 660 +/- 44 and 706 +/- 32 g and 0 and 12 months, respectively (p = 0.156). These parameters did not change in controls. Sequential bone biopsy in 3 cases also supported these changes. We conclude that IVC not only suppresses bone turnover, but that it also restores decreased bone mass in HD patients with OF.

Adult↗
PubMed1995

[Uptake of Tc-99m hexakis 2-methoxy isobutyl isonitrile in lung or mediastinal lesions by SPECT].

The uptake of Tc-99m hexakis 2-methoxy isobutyl isonitrile (99mTc-MIBI) was evaluated in 18 patients with various lung or mediastinal lesions by SPECT. The patients consisted of seven with lung cancers, three with lung cancers who were treated with chemotherapy and were disease free, and one each with malignant lymphoma, esophageal cancer, thyroid cancer involving the mediastinum, malignant thymoma, pneumonia, granuloma, sarcoidosis and neurinoma. SPECT imaging (30 min, 600 MBq) was performed after intravenous injection. Strong uptake of 99mTc-MIBI was noted in all malignant tumors except malignant lymphoma. The mean tumor to normal lung tissue uptake ratio (T/N ratio) was 2.26. The mean in lung cancer was 2.31. Slight accumulation was present in pneumonia and granuloma (mean T/N = 1.24). No accumulation was present in a case of non-Hodgkin's lymphoma and neurinoma. Moderate uptake was noted in one case of sarcoidosis (T/N = 1.46). No abnormal accumulation of 99mTc-MIBI was seen in post-therapeutic lung cancer. These results suggested that 99mTc-MIBI SPECT could be useful in differentiating between malignant and benign lesions.

Adult↗
PubMed1995

Effects of one-year cadmium exposure on livers and kidneys and their relation to glutathione levels.

To study the effects of a long-term cadmium exposure on livers and kidneys, rats were administered cadmium chloride (0.228 mg Cd/kg, 3 days/week ip), for one year. Significant accumulation of cadmium was observed in livers (183 +/- 40 micrograms/g liver) and kidneys (92 +/- 17 micrograms/g kidney). Serum urea nitrogen and creatinine levels were significantly elevated in the cadmium-treated rats, while liver function tests were minimally affected. Histological observations showed interstitial fibrosis with minimal cell necrosis and inflammatory cell infiltration in livers, and apparent degeneration of proximal tubules and infiltration of inflammatory cells in parenchyma of kidneys. Lipid peroxidation in livers and kidneys, as assessed by thiobarbituric acid reactive substances, revealed no differences between the cadmium-treated rats and the controls. Glutathione contents were significantly increased in the cadmium treated rats both in livers (p < 0.001), and in kidneys (p < 0.001) compared with the controls. Increased glutathione levels in livers may contribute, in part, to the prevention of serious hepatotoxicity during chronic cadmium exposure, while nephrotoxicity due to cadmium may not be prevented by glutathione.

Animals↗
PubMed1995

[Body surface isopotential T map and ventricular volume characteristics in secundum atrial septal defect].

Body surface isopotential T map was analyzed to detect right ventricular volume and pressure overloads in 25 patients with secundum atrial septal defect. Three patterns were distinguished: the T map resembling normal (type A, n = 9); that with isolated negative area in positive area (type B, n = 11); and that with rightward movement of maximum (type C, n = 5). Right ventricular end-diastolic volumes in type B (161 +/- 19% of normal; %N) and C (175 +/- 40% N) were significantly (p < 0.01) greater than those in control (100 +/- 9% N) and type A (113 +/- 18% N). Right ventricular systolic pressure in type C (48 +/- 11 mmHg) was significantly (p < 0.01) higher than those in control (30 +/- 5 mmHg), type A (31 +/- 4 mmHg) and type B (34 +/- 5 mmHg). These results suggest that the cases with type B have right ventricular volume overload, and those with type C have both volume and pressure overloads.

Body Surface Potential Mapping↗
PubMed1994

Endobronchial metastasis from a primary uterine osteosarcoma in a patient with multiple myeloma: report of a case.

We present herein the case of a 75-year-old woman with multiple myeloma who underwent a left lower lobectomy for endobronchial metastasis from an uterine osteosarcoma. She had initially been admitted to our hospital for chemotherapy more than 1 year earlier, soon after which a primary uterine osteosarcoma was discovered and a total abdominal hysterectomy and bilateral salpingo-oophorectomy performed. One year after the operation, the patient developed hemoptysis. A flexible bronchofiberscopy demonstrated a polypoid mass obstructing the left basal bronchus, and computed tomographic scans showed three pulmonary nodules. Surgery was performed to control the hemoptysis. At thoracotomy, two metastatic nodules were identified in the left lower lobe, and the endobronchial extension of the tumor was resected en bloc with the left lower lobe. The tumor was diagnosed as lung metastasis from the uterine osteosarcoma. Although further lung tumors have recently appeared, the patient has remained well for the 3 years since her last operation without any hemoptysis.

Aged↗
PubMed1994

Balloon pulmonary valvuloplasty for double outlet right ventricle with valvular pulmonary stenosis.

A male neonate presented with cyanosis. Echocardiograms showed a double outlet right ventricle, an absent outlet septum, a subaortic ventricular septal defect and valvular pulmonary stenosis. Balloon pulmonary valvuloplasty was performed at 19 days of age, resulting in an immediate increase of the systemic arterial oxygen saturation from 67 to 87%. As far as could be found, this is the first report of a patient with a double outlet right ventricle without the outlet septum who was clinically observed and underwent balloon pulmonary valvuloplasty.

Catheterization↗
PubMed1994

Histopathologic findings of lung vessels in five children with primary pulmonary hypertension.

A histopathologic study was carried out on pulmonary vessels of lung tissues from 5 children with primary pulmonary hypertension (PPH), in whom diagnosis was made on the basis of cardiac catheterization. Histological sections of lung were obtained in 4 patients by open lung biopsy and in one patient by closed needle necropsy soon after death. In all cases the vascular diseases were classified as grade 6 of the Heath-Edwards. Morphologic studies of small pulmonary arteries revealed medial hypertrophy (41.0%), intimal cellular proliferation (2.5%), intimal fibroelastic proliferation (36.9%) and medial destructive changes (19.6%) such as dilatation lesions, plexiform lesions, arteritis, or fibrinoid necrosis. Index of pulmonary vascular disease (IPVD) was 1.6 to 3.4 (mean 2.5). The advancement of these pulmonary changes sufficiently explains the extremely poor prognosis of children with PPH.

Adolescent↗
PubMed1994

Changes in molecular pattern of atrial natriuretic peptide in hemodialysis patients.

An attempt was made to clarify whether the molecular forms of atrial natriuretic peptide (ANP) in the plasma of stable hemodialysis patients differ from those of healthy volunteers, and whether the ANP molecular forms in plasma might change during hemodialysis treatment. Ten stable hemodialysis patients with no clinical signs of cardiac disease were treated for 4 hours by a hollow fiber-type dialyzer. Plasma ANP concentrations before dialysis were 210 +/- 101.6 pg/ml (mean +/- SD), which were significantly higher than that of volunteers (59.2 +/- 37.2 pg/ml, n = 25). They were significantly decreased to 71.6 +/- 60.1 pg/ml after dialysis. Molecular patterns of ANP were measured by gel permeation chromatography and reverse-phase high performance liquid chromatography. Immunoreactive alpha-ANP peaks of GPC, which co-migrated with authentic alpha-, beta-, and gamma-ANP, were supposed to be alpha-, beta-, and gamma-ANP. The plasma of four patients contained a beta-ANP peak before dialysis, and three of the four still contained a beta-ANP peak after dialysis. These results showed that the middle-molecular-weight ANP, which co-migrated with authentic beta-ANP and is supposed to be beta-ANP, may particularly be secreted in clinically stable hemodialysis patients.

Adult↗
PubMed1994

[Tetralogy of Fallot with absent pulmonary valve: a successful case by total corrective surgery in 25 days old infant].

A 25 days old neonate of tetralogy of Fallot with absent pulmonary valve underwent total corrective surgery which consisted of VSD patch closure, resection of anterior wall of both pulmonary arteries and right ventricular outflow tract reconstruction using a monocuspid equine pericardial patch. Postoperatively, the right pulmonary artery diameter decreased from 17.8 mm (307%N) to 7.5 mm (129%N) and the left pulmonary artery diameter from 16.9 mm (338%N) to 8.3 mm (166%N). The patient was weaned from the ventilator 2 days after operation, whose post-operative course was uneventful. Total corrective surgery may provide a great success to symptomatic patients during the neonatal period.

Cardiac Surgical Procedures↗
PubMed1994

Electrophoretic free mobility and viability of microbial cells: a preliminary study in preparation for space experiments.

Electrophoretic free mobilities (EFM) of four fungal spores and five bacterial cells were determined in 7 mM triethanolamine/acetate (TEA) buffer by means of microscopic electrophoresis (ME) and free flow electrophoresis (FFE). Spores of Aspergillus terreus, Penicillium citrinum, Gliocladium virens, and Rhizopus oryzae had similar EFM from 2.2 to 3.1 microns sec-1/V cm-1. The resolution of the spore mixture by FFE was therefore determined to be poor. Bacterial cells of Salmonella typhimurium LT2 mutants showed a distinctive EFM from 0 to 4.2 microns sec-1/V cm-1, which is a large enough difference to produce a clear separation of each mutant type from the mixture in FFE. The differences in the EFM of bacteria result from defective structures in the lipopolysaccharide of their outer membranes. The viability of bacteria in TEA buffer at 4 degrees C was investigated, and it was found to be stable for 14 days. This period is long enough to allow the performance of space experiments.

Aspergillus↗
PubMed1994

Disease of the left ventricle in pulmonary atresia with intact ventricular septum. The limiting factor for long-lasting successful surgical intervention?

Eight hearts with pulmonary atresia with intact ventricular septum were studied grossly and microscopically. The right ventricle was composed of inlet, infundibular, and trabecular portions in two hearts, without trabecular portions in three hearts, and consisted of an inlet part only in another three hearts. Pulmonary atresia was classified as membranous in two hearts; the other six hearts had muscular atresia. The left ventricle showed a range of abnormalities, albeit mostly discrete. A mitral valve with short tendinous chords was present in four hearts; one of these had a cleft mitral valve. All hearts (except the heart of a 1-day-old neonate) had a prominent subaortic septal bulge. All hearts had left ventricular hypertrophy, which exceeded twice the standard deviation of normal in two patients. None of the hearts had histologic features of hypertrophic cardiomyopathy. The density of intramyocardial coronary arteries was normal in each patient, but medial thickening (20 to 100 microns diameter arteries) had occurred in four patients. Signs of acute myocardial ischemia (hydropic cell swelling) were present in all; one heart (the oldest case of 6 months) contained areas of replacement fibrosis and calcifications indicative of previous infarction. Quantification of the volume density of endomysial (interfiber) collagen (Picrosirius red microspectrophotometry) showed high levels in all, within the range of normal in five patients, but exceeding twice the standard deviation of normal in three patients. In all cases the values obtained in the subendocardial layers were higher than those obtained subepicardially. The observations show that the left ventricle in hearts with pulmonary atresia with intact ventricular septum contains abnormalities that may render the left ventricle less capable to cope with a volume load. The high values of endomysial (interfiber) collagen suggest chronic ischemia in relation to left ventricular hypertrophy as the main mechanism involved. Therefore, as a late consequence, the left ventricle could be the limiting factor for long-lasting successful surgical intervention.

Coronary Vessels↗
PubMed1992

Central alpha-adrenoceptor subtypes involved in the emetic pathway in cats.

The intracerebroventricular (i.c.v.) injection of clonidine, xylazine, adrenaline and methoxamine elicited dose-dependent vomiting in cats in that order of potency. The vomiting induced by clonidine, xylazine and adrenaline was antagonized by i.c.v. yohimbine and phentolamine possessing alpha 2-adrenoceptor-blocking activity, but not by prazosin showing alpha 1-adrenoceptor-blocking activity. In contrast, methoxamine-induced vomiting was antagonized by prazosin, but not by yohimbine. The vomiting induced by xylazine and adrenaline was not prevented by i.c.v. 6-hydroxydopamine treatment, but was prevented by i.c.v. reserpine treatment. Ablation of the area postrema with some damage to extremely adjacent areas abolished the vomiting induced by each alpha-adrenoceptor agonist. These results indicate that both central alpha 1- and alpha 2-adrenoceptors are involved in the emetic pathway in cats, although alpha 2-adrenoceptors seem to have the main role. It is also suggested that monoamines, and in particular 5-hydroxytryptamine in the brain, are involved in the regulation of alpha-adrenoceptor-mediated vomiting.

Adrenergic alpha-Agonists↗
PubMed1992

Endothelin receptors in human parathyroid gland.

We studied whether specific receptors for endothelins (ETs) exist in human parathyroid tissues and whether ETs may have any effect on secretion of PTH from parathyroid cells. Binding studies using [125I]ET-1 to the parathyroid membranes obtained from patients with hyperparathyroidism (2 adenomas, 2 hyperplasias) revealed that ET-1 competitively inhibited the binding of [125I]ET-1 to the membranes (the apparent Kd: 62 +/- 18 pM), whereas ET-3 showed biphasic and less steep inhibition curve than ET-1 in all tissue membranes examined. Northern blot analysis of poly(A)+ RNA from the parathyroid adenoma clearly demonstrated gene expression of both ETA and ETB receptors as well as preproET-1. ET-1 inhibited basal PTH secretion from dispersed adenoma cells more potently than ET-3. The present study clearly demonstrates the presence of both ETA and ETB receptor subtypes in human parathyroid tissues through which ETs may modulate PTH secretion in an autocrine and/or paracrine manner.

Adenoma↗
PubMed1992

Estimation of right ventricular pressure in children by thallium-201 myocardial imaging using single-photon emission computed tomography.

Thallium-201 myocardial imaging using single-photon emission computed tomography was performed to estimate right ventricular (RV) systolic pressure in 34 children (aged 4.1 to 16.1 years, mean 7.9 +/- 2.9). Acquisition of the images was performed using a semicircular arc of 180 degrees. On a short-axis slice, a line drawn perpendicular to the ventricular septum so as to cross the RV free wall showing maximum uptake was defined as the region of interest. Thallium-201 counts in regions of interest over both RV and left ventricular (LV) free walls were measured. The ratio of RV-to-LV peak thallium-201 counts was compared with RV peak systolic pressure and the ratio of RV-to-LV peak systolic pressure measured at cardiac catheterization. Both RV peak systolic pressure and the ratio of RV-to-LV peak systolic pressure correlated well with the ratio of RV-to-LV peak thallium-201 counts (r = 0.95 and 0.96, respectively). The ratio of RV-to-LV peak thallium-201 counts greater than or equal to 0.45 could predict RV pressure overloading with a sensitivity of 92%, and a specificity of 88%. Thus, the quantitative analysis of thallium-201 myocardial imaging using single-photon emission computed tomography permits the noninvasive and accurate estimation of RV systolic pressure in children.

Adolescent↗
PubMed1992

Haloalkaliphilic maltotriose-forming alpha-amylase from the archaebacterium Natronococcus sp. strain Ah-36.

A haloalkaliphilic archaebacterium, Natronococcus sp. strain Ah-36, produced extracellularly a maltotriose-forming amylase. The amylase was purified to homogeneity by ethanol precipitation, hydroxylapatite chromatography, hydrophobic chromatography, and gel filtration. The molecular weight of the enzyme was estimated to be 74,000 by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The amylase exhibited maximal activity at pH 8.7 and 55 degrees C in the presence of 2.5 M NaCl. The activity was irreversibly lost at low ionic strength. KCl, RbCl, and CsCl could partially substitute for NaCl at higher concentrations. The amylase was stable in the range of pH 6.0 to 8.6 and up to 50 degrees C in the presence of 2.5 M NaCl. Stabilization of the enzyme by soluble starch was observed in all cases. The enzyme activity was inhibited by the addition of 1 mM ZnCl2 or 1 mM N-bromosuccinimide. The amylase hydrolyzed soluble starch, amylose, amylopectin, and, more slowly, glycogen to produce maltotriose with small amounts of maltose and glucose of an alpha-configuration. Malto-oligosaccharides ranging from maltotetraose to maltoheptaose were also hydrolyzed; however, maltotriose and maltose were not hydrolyzed even with a prolonged reaction time. Transferase activity was detected by using maltotetraose or maltopentaose as a substrate. The amylase hydrolyzed gamma-cyclodextrin. alpha-Cyclodextrin and beta-cyclodextrin, however, were not hydrolyzed, although these compounds acted as competitive inhibitors to the amylase activity. Amino acid analysis showed that the amylase was characteristically enriched in glutamic acid or glutamine and in glycine.

Amino Acids↗