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Biomedical subjects

T Ohta

Publications and source records attributed to T Ohta.

At least 577 records · Page 32Linked to original sources
PubMed1996

Exophytic intraspinal extension of cerebellar glioma--case report.

A 49-year-old female presented with a 2-year history of occipitalgia, a 3-month history of dysesthesia, and dull sensation of the left upper extremity. T1-weighted magnetic resonance (MR) imaging revealed a low-intensity mass without gadolinium-diethylenetriaminepenta-acetic acid enhancement extending from the cisterna magna to the spinal canal. T2-weighted MR imaging revealed a high-intensity mass. Neuroradiological findings were inadequate to establish the mass as intra-axial or extra-axial. Operative findings discovered an intra-axial mass which was totally removed. Histological examination found the mass was an oligoastrocytoma. Cerebellar glioma developing exophytically is very rare. Adequate surgical removal is possible and likely to be curative if total.

Cerebellar Neoplasms↗
PubMed1996

Paraclinoid carotid artery aneurysms with the dome eroding the anterior clinoid process: preoperative depiction of topography and surgical tactics--two case reports.

A 70-year-old male and a 55-year-old female presented with unruptured aneurysms in the clinoid segment of the carotid artery. Intraoperative rupture during removal of the anterior clinoid process resulted in unintended carotid artery occlusion in the former patient, causing hemispherical infarction and death. However, the aneurysm was successfully clipped due to preoperative recognition of the aneurysmal dome in the clinoid process in the latter. Magnetic resonance angiography and three-dimensional computed tomography angiography source images provide detailed visualization of the topographic anatomy around the paraclinoid aneurysms and are helpful for definite surgical planning.

Adenoma↗
PubMed1996

Dietary wheat gluten alleviates the elevation of serum transaminase activities in D-galactosamine-injected rats.

The effects of dietary protein on the elevation of activities of serum aspartate aminotransferase (AST) and alanine aminotransferase (ALT) in D-galactosamine-injected rats were investigated. The rats fed with experimental diets containing test protein sources for 2 weeks were injected with D-galactosamine (0.8 g.kg-1 body weight). The activities of AST and ALT in serum were assayed after 20 h. According to the results, these enzyme activities in the rats fed 40% casein diet were higher than those of 5, 10, or 20% casein groups. In the 40% gluten group, these enzyme activities were lower than in the 40% casein group. This difference was not considered to be caused by the deficit of L-lysine and L-threonine in gluten. The extent of the reduction of UTP and UDP-glucose in liver by D-galactosamine was almost the same in the 40% gluten and 40% casein groups. These results suggest that levels and quality of dietary protein affect the susceptibility of animals to the hepatotoxin D-galactosamine and dietary gluten was found to alleviate the elevation of serum transaminases in rats by the drug.

Alanine Transaminase↗
PubMed1996

Purification and properties of alpha-amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSD), key enzyme of niacin synthesis from tryptophan, from hog kidney.

alpha-Amino-beta-carboxymuconate-epsilon-semialdehyde decarboxylase (ACMSD) (EC 4.1.1.45) was purified to a homogeneous state from hog kidney cytosol by ammonium sulfate fractionation, Butyl-Toyopearl 650, hydroxyapatite, DEAE-Sephadex, Toyopearl HW55, Superdex 200 and TSK-gel G3000SW chromatographies. The molecular weight of the enzyme was estimated to be 58,000 by TSK-gel G3000SW gel filtration. The optimum pH (constant concentration) was 7.5. The Km for alpha-amino-beta-carboxymuconate-epsilon-semialdehyde was 1.61 x 10(-5) M. The activity of purified enzyme was inhibited by some chemical modifying reagents such as monoiodoacetic acid and p-(chloromercuri) benzoic acid. A sulfhydryl group was deduced to exist in the active site of the enzyme.

Ammonium Sulfate↗
PubMed1996

Isolation of a cosmid clone corresponding to an inv(21) breakpoint of a patient with transient abnormal myelopoiesis.

Transient abnormal myelopoiesis (TAM) is a leukemoid reaction occurring occasionally on Down syndrome (DS) newborn infants. It has been hypothesized that "disomic homozygosity" in 21-trisomic cells plays an important role in the genesis of TAM, and the putative TAM gene was suggested to be mapped at a 21q11 region. We encountered a DS-associated TAM infant with a 47,XY,inv(21)(q11.1q22.13),+inv(21)(q11.1q22.13) karyotype. On the basis of another presumption that in this patient the putative TAM gene is disrupted by the break, we tried to isolate a breakpoint DNA. FISH analysis with cosmid clones corresponding to various sequence-tagged-site (STS) markers mapped at around 21q11.1-q11.2, we confirmed that the proximal breakpoint of the inv(21) was located between two STSs, G51E07 and D21S215, the latter locus being consistent with the previous tentative mapping. After construction of a cosmid contig encompassing between the two markers, we have isolated a cosmid clone corresponding to the proximal breakpoint of the inversion. This breakpoint was located near a previously identified duplicated region that is homologous to the sequence at 21q22.1. The isolated cosmid clone is useful for analysis of other TAM patients and for a search for a transcript at or flanking the breakpoint.

Adult↗
PubMed1996

[Detection of bone metastasis by serial measurement of C-terminal telopeptide of type I collagen in patients with malignancy].

Measurements of biochemical markers specific to bone resorption are known to be useful in evaluation of skeletal metastasis. However, most of previous studies were performed cross-sectionally and sensitivity for detection of early bone metastasis was not satisfactory. Since basal levels of bone markers differ significantly individually, longitudinal studies would be preferable to evaluate small metabolic changes such as in early skeletal metastasis. Thus, we performed serial measurements of serum c-terminal telopeptide of type I collagen (ICTP), a bone resorption marker, in patients with malignancy and evaluated its clinical significances for detection of bone metastasis, comparing with measurements of propeptide of type I procollagen (PICP) and tumor markers. In total, 43 patients (41 of them are breast cancer), serial serum samples were obtained during 0.5 to 2.4 years (mean 1.4 years). In all of nine patients, who developed bone metastasis, serum ICTP level increased, and by successful treatment to the metastatic lesions, ICTP level decreased, while in some cases, tumor markers remained to be elevated. PICP was less sensitive and specific for detection of bone metastasis. Thus, serial measurement of ICTP is suggested to be useful for detection and evaluation of therapeutic responses in patients with bone metastasis.

Biomarkers, Tumor↗
PubMed1996

[Comparative study on biological difference between gastric cancer and colorectal cancer].

In this study, we investigated the clinico-pathologic characteristics of patients with adenocarcinoma of the stomach and those with colorectal carcinoma to compare early progression patterns of both tumors. Histologically, gastric and colorectal adenocarcinomas showed similar progression patterns, including the incidence of submucosal invasion, lymphatic infiltration and lymph node metastasis. One striking finding was in gross appearance in born tumors. In contrast to most gastric well differentiated adenocarcinoma (DTA), which showed superficial growth, colorectal DTAs mainly showed polypoid growth. However, the superficial-type colorectal DTAs invaded the submucosal layer more frequently than did polypoid DTAs and gastric DTAs. These findings indicate that superficial-type colorectal DTAs grow more rapidly and aggressively than do polypoid DTAs and gastric DTAs. In order to elucidate growth rates between gastric cancer and colorectal cancer with hepatic metastasis doubling time was measured by exponential growth of tumor marker (CEA or AFP). The doubling time of liver metastases calculated from tumor markers was 26.6 +/- 10.8 days for stomach cancer and 57.8 +/- 35.4 days for colorectal cancer; accordingly doubling time for gastric cancer was approximately half of that for colonic cancer. However, there were no other factors (age, sex, site, histologic type in stomach, tumor marker production, etc.) influencing doubling time.

Adenocarcinoma↗
PubMed1996

[A new strategy for the therapy of pancreatic cancer by proton pump inhibitor].

Bafilomycin A1 is a specific inhibitor of vacuolar type proton pump (V-ATPase). This study was designed to examine the effect of bafilomycin A1 on the growth of Capan-1 human pancreatic cells which overexpress V-ATPase. Nude mice bearing a xenografted tumor of Capan-1 cell line were treated for 4 weeks with bafilomycin A1 (1.0 mg/kg/day). This treatment inhibited tumor growth, which was significantly reduced as compared with controls after 21 days (p < 0.05). However, there were no significant differences in body weights between groups. Microscopically, a large number of tumor cells in the treated group showed signs of apoptosis. These findings suggest that apoptosis induced by bafilomycin A1 was the event involved in suppression of tumor growth in vivo.

Animals↗
PubMed1996

[Inhibitory effect of FOY-305 on liver metastasis of the pancreatic cancer].

The potential for hepatic metastasis in nude mice was studied by the intrasplenic implantation method with five human pancreatic cancer cell lines, Capan-1, BxPC-3, AsPC-1, Panc-1, and MIAPaCa-2, especially in relation to serine protease expression, including urokinase-type plasminogen activator and pancreatic trypsinogen 1 (cationic form). The inhibitory effect of a serine protease inhibitor agent, FOY-305, on hepatic metastasis was also a assessed. As a result, the potential for hepatic metastasis was well correlated with expression of pancreatic trypsinogen 1 in these cell lines, and the incidence of metastasis was significantly decreased by FOY-305. These findings suggest that pharmacologic inhibition of serine protease activity may be a new strategy for the therapy of pancreatic cancer metastasis.

Animals↗
PubMed1996

[Transfection].

Transfection is a method to introduce DNA into mammalian cells. Calcium phosphate-mediated transfection is well used as one of the methods for transfection. The basic protocol is simple and does not require the elaborated instruments. It has been applied to introduce the heterogeneous DNA for integration into and expression from the chromosome. The proteins so expressed can be further analysed for their function and structure. In this section, a protocol for high efficiency transfection with calcium phosphate and its applications to membrane proteins are introduced. By exploiting the various transfection methods as tools for analyses such as chimeric gene expression and the site-directed mutagenesis, in the Na+, K+ -ATPase the N-terminus of alpha-subunit was shown to be a Na+ sensor, the ouabain binding site was found between the amino acid residues 69 and 200, and the assembly site of alpha- and beta-subunits was located within the 26 residues. In the case of Ca+ -ATPase, the newly isolated isoform was revealed to possess the same ATP-affinity as the already known ones, and the calmodulin-binding site was also shown to interact with the Na+, K+ -ATPase alpha-subunit.

Animals↗
PubMed1996

[Serodiagnosis of fungal infection].

Serum samples from patients with candidiasis were assayed for Candida mannan by the enzyme-linked immunosorbent assay using anti-Candida albicans and anti-Candida krusei antibodies (ELISA, n = 81), for heat-labile glycoprotein by the latex agglutination test (Cand-Tec, n = 69), for D-arabinitol by the enzymatic fluorometric method, and for beta-D-glucan by the chromogenic substrate method (the G test, n = 14). The sensitivities and the specificities were 83% and 99% for mannan, 61% and 85% for heat-labile glycoprotein, 50% and 91% for D-arabinitol/creatinine ratio (> or = 1.5 mumol/mg), and 100% and 71% for beta-D-glucan (> or = 30 pg/ml), respectively. No positive reactions for the Cand-Tec and the ELISA were observed in patients with candidiasis by Candida glabrata. The sensitivity of the Cand-Tec increased with the number of samples available per patient, which was lower for patients with hematological malignancies compared with patients without hematological malignancies (25% vs. 59%). For the ELISA, however, the sensitivity was not related to the presence of hematological malignancies, nor was it related to the number of samples per patient. Among the serodiagnostic methods examined, the ELISA may be most useful in diagnosing candidiasis and in predicting the prognosis of candidiasis caused by medically important Candida strains. Of 21 patients with aspergillosis, 19 patients had antigenemia detected by the ELISA, and only 5 patients showed positive reactions with the LA test(Sanofi Diagnostics). Five of six patients with cryptococcosis revealed positive reactions with both the ELISA and the LA test(Eiken).

Antigens, Fungal↗
PubMed1996

[Hemodynamic simulation study of cerebral arteriovenous malformations: changes of wall stress and early detection of NPPB].

Obliteration procedures for large high-flow arteriovenous malformations (AVM) were simulated using a compartmental flow model to investigate the role of altered autoregulatory conditions in the development of hyperperfusion and normal perfusion pressure breakthrough (NPPB). Since the arterioles are primarily responsible for autoregulatory function, the role of these structural changes on the development of hyperperfusion was also studied by evaluating the wall thickness (T), internal radius (Ri) and tangential wall stress (sigma). As the AVM flow was decreased during the obliteration procedures, the perfusion pressure (delta P) of the brain tissue surrounding the AVM increased. When the autoregulatory condition was impaired [AR (-)] and the lower limit of the autoregulatory pressure range (LAR) was shifted from 60 mmHg (LAR60) to 40 mm Hg (LAR40), the flow volume in the surrounding brain (Fb) increased markedly, from 67 ml/100g/min to 92 ml/100g/min, with the progress of the obliteration procedures. In these conditions, T/Ri was supposed to be constant and sigma value increased uniformly. In the presence of the autoregulatory mechanism [AR (+)], T/Ri increased against increasing delta P, which resulted in smaller sigma value than that under AR (-) conditions. When the contracted vascular wall yielded on the process of increasing wall stress, delta P and feeder pressure (Pf) decreased to some degree. Concomitantly increase of the sigma value and marked hyperperfusion developed in the brain. The yield of the contracted vascular wall would result in the decrease of a pressure gradient across the arteriole and the reciprocal increase of pressure load on the walls of the capillary and venula, which might lead to NPPB. Since the decrease of delta P or Pf during the progress of the obliterating procedures is considered specific to the appearance of hyperperfusion or NPPB, monitoring these parameters would be useful for its early detection. If the upper limit of the autoregulatory pressure range was assumed to decrease and become the yield point in the brain surrounding high flow AVMs, hyperfusion or NPPB could be considered to develop in the conditions with the autoregulatory pressure range being narrowed and/or shifted to the lower pressure level. Induced systemic hypotension was found to be effective in reducing the magnitude of Fb, delta P, and Pf when induction was appropriately performed in stepwise fashion. T/Ri and sigma were kept in narrow ranges compared to those before induction of hypotension.

Arterioles↗
PubMed1996

[Fundamental study for lung-cancer screening by helical CT. First report: evaluation of radiation dose and image quality using a phantom].

In a fundamental study on the early detection of lung cancer by helical computed tomography (CT), we evaluated the effect of scanning parameters on radiation dose and image quality using a phantom. The exposure dose at the center of the gantry and the absorbed dose at the center of an acrylic phantom changed linearly in proportion to tube current. On the other hand, as the table feed speed increased, the rate of reduction in these doses became smaller. While the change in CT value of an acrylic sphere in the longitudinal axis, the difference in CT value between an acrylic sphere and styrofoam in the horizontal plane and the CT profile curve of an acrylic sphere in the horizontal plane did not change according to tube current, an increase in table feed speed brought about the degradation of these items. In conclusion, reduction of the tube current in helical scanning is able to reduce radiation dose without causing a significant change in image quality, but an excessive increase in table feed speed does not reduce radiation dose effectively and is associated with degradation in image quality.

Humans↗
PubMed1996

Preoperative embolization of highly vascular brain tumors: clinical and histopathological findings.

This report concerns the clinical and histopathologic findings in five patients with meningioma and two with hemangioblastoma who underwent embolization with polyvinyl alcohol (PVA) particles before surgery. Angiography revealed loss of tumor stain from the main feeders in all seven patients, with markedly decreased contrast enhancement of computed tomography (CT) and magnetic resonance imaging (MRI) in six of them. Tumor excision was readily accomplished in all instances, with minimal bleeding from the tumor. In the patient operated 1 day after embolization there were almost no necrotic lesions, even though hemorrhage, presumably due to the surgical procedure was noted. Necrotic lesions and island-like residual tumor cells around the vessels were seen in the patient operated two days after embolization. Extended necrotic lesions were noted among patients who underwent surgery at day 4 and thereafter. Revasculization was not found, even in the patient operated one week after embolization. Massive bleeding (due presumably to the surgical procedure, suggesting recanalization) was noted in the tissue of a hemangioblastoma patient who underwent surgery 13 days after embolization, even though tumor excision was easy. In the patient subjected to the surgical procedure 694 days following embolization, the CT and MRI performed 2 months later, revealed contrast enhancement similar to that seen before the operation. Moreover, angiography, done after 5 months, demonstrated tumor stain as had been noted before embolization. The histopathologic examination of this case reveal the presence of extended necrotic lesions, a large number of macrophages that contained PVA particles, and destruction of the walls of the onceoccluded vessels. In addition, there were many blood-filled vessels that had achieved recanalization. These findings suggest that it is desirable to operate within 7 days after embolization, since recanalization occurs during this period, even though PVA particles remain unabsorbed for a long time.

Adult↗
PubMed1996

[Recent progress in development of psychotropic drugs (5)--Hypnotics].

Regarding the treatment of insomnia, it is said that a considerable degree of advancement has been made to date in terms of controlling toxicity, preventing the development of tolerance and avoiding addiction, which were often observed when administering barbiturates. Nevertheless, the majority of hypnotics used today, which are benzodiazepines, still retain certain side effects such as hangover effects, development of dependence, rebound insomnia as a withdrawal symptom, muscular atonia resulting in falling down and causing bone fracture, inhibition of respiratory system, negative interaction with alcohol, etc. The current trend of selecting hypnotics is to use short-half-life agents. However, there are yet other problems such as cognitive disorders including amnesia, rebound insomnia and increased anxiety during the daytime. In order to cope with these problems, three new hypnotics have recently been developed. They are non-benzodiazepine derivatives and considered to be safer than the others, because they are supposed to cause less side effects than conventional hypnotics. The pharmacokinetic characteristics of these new hypnotics can be summarized as follows: 1) these hypnotics have selective affinity to benzodiazepine receptor omega-1 subtype although the agent itself does not belong to the benzodiazepine derivative family; 2) the half-life-time in the serum is extremely short, namely 1-2 hours; 3) they increase the level of slow waves (delta-wave) during sleep; 4) they have a lesser effect toward atonic muscle and amnestic thought and behavioral disturbance as compared to conventional hypnotics; and 5) the risks of developing drug tolerance and reciprocal negative effects with alcohol are smaller. Consequently, we can expect that these new hypnotics will bring a certain advantage, especially regarding the avoidance of hypnotics-induced side effects in the course of clinical treatment of insomnia in the future.

Acetamides↗
PubMed1996

[Early carcinoma of the biliary tract].

Early carcinoma of the biliary tract was defined as cancer cell invasion limited to the mucosal or muscularis propria in the case of the gallbladder, to the mucosal or fibro-muscular layer in the case of carcinoma of the bile duct and to the sphincter of Oddi in the case of the papilla of Vater from a study on the correlation between the depth of cancer invasion and the result of surgery. A few cases, however, have lymph node metastasis, venous invasion, perineural infiltration or involvement of the lymphatic vessels. The surgical procedures should therefore be selected in order to have a good chance for long-term survival. The importance of systematic lymph node dissection to improve survival is emphasize, even in patients with early biliary tract cancer.

Biliary Tract Neoplasms↗