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Biomedical subjects

A Takagi

Publications and source records attributed to A Takagi.

At least 217 records · Page 12Linked to original sources
PubMed1990

Significant increase of 8-hydroxydeoxyguanosine in liver DNA of rats following short-term exposure to the peroxisome proliferators di(2-ethylhexyl)phthalate and di(2-ethylhexyl)adipate.

8-Hydroxydeoxyguanosine (8-OH-dG) levels were examined in liver and kidney DNA after di(2-ethylhexyl)phthalate (DEHP), di(2-ethylhexyl)adipate (DEHA) and phthalic anhydride administration to male 6-week-old F-344 rats in the diet at concentrations of 1.2, 2.5 and 1.5%, respectively. Significant increases in 8-OH-dG levels were observed only in the liver (target organ of DEHP and DEHA carcinogenesis) DNA after 1 and 2 weeks of treatment with DEHP and DEHA, respectively. The results suggest the involvement of oxidative DNA damage in hepatocarcinogenesis by peroxisome proliferators.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1990

Atrial natriuretic peptide in patients with the syndrome of inappropriate antidiuretic hormone secretion and with diabetes insipidus.

To examine a possible role for atrial natriuretic peptide (ANP) in water and sodium metabolism disturbances associated with abnormal vasopressin (AVP) secretion, we measured plasma ANP concentrations in 15 patients with the syndrome of inappropriate antidiuretic hormone secretion (SIADH) and in 17 patients with central diabetes insipidus (DI). The mean plasma ANP concentration (30.2 +/- 10.4 pmol/L) in SIADH patients who had hyponatremia, plasma hypoosmolality, hyperosmolar urinary compared to plasma sodium levels, and increased plasma AVP levels relative to plasma osmolality was significantly higher than that in normal subjects (12.6 +/- 4.9 pmol/L), although there was a considerable individual variation in plasma ANP ranging from normal to clearly elevated levels (15.1-47.0 pmol/L). When hyponatremia was corrected by water restriction or demeclocycline administration, plasma ANP levels decreased significantly and fell into the normal range (12.5 +/- 4.3 pmol/L). DI patients who complained of polyuria and polydipsia and had hypoosmolar urine, normal or elevated plasma sodium concentrations, and decreased plasma AVP levels relative to plasma osmolality, on the other hand, had a significantly lower mean plasma ANP level (7.6 +/- 2.9 pmol/L) than normal subjects. There was, again, a considerable overlap between plasma ANP levels in individual DI patients (4.2-13.9 pmol/L) and those in normal subjects. Treatment with 1-desamino-8-D-arginine vasopressin resulted in a significant increase in the mean plasma ANP level (18.6 +/- 8.0 pmol/L). There were no significant correlations between plasma ANP and AVP levels in either group of patients. The results indicate that ANP secretion is modulated by changes in plasma volume consequent to abnormal AVP secretion, which may have a pathophysiological significance in maintaining volume homeostasis.

Adolescent↗
PubMed1990

Computer-aided three-dimensional reconstruction and measurement for multiple-electrode cochlear implant.

To assist surgeons in performing multiple-electrode cochlear implant operations, the spatial relations between middle and inner ear structures in six normal temporal bones were studied using the computer-aided 3-D reconstruction method. When viewed through the external auditory canal, the approach used for electrode insertion, and the relation of the malleus to the helicotrema or the scala vestibuli in the second turn of the cochlea were found to vary considerably. In contrast, when viewed from the same transmeatal approach, both the direction and the distance from the stapes footplate to the scala vestibuli of the second turn of the cochlea and helicotrema were found to be quite stable. We concluded that the stapes footplate was a better landmark than the malleus when approaching the helicotrema and scala vestibuli of the second turn of the cochlea during multiple-electrode cochlear implant surgery.

Adolescent↗
PubMed1990

[Ruptured arteriovenous malformation during pregnancy with special reference to diagnostic X-ray exposure. Case report].

A 32-year-old female (gravida 2, para 2) was admitted at 15 weeks of gestation with a chief complaint of left homonymous hemianopsia accompanied by frontal headache. Computed tomography scan and cerebral angiography were performed with the lead shield and probe for X-ray exposure placed on the patient's body. Angiography revealed an arteriovenous malformation (AVM) located in the posterior part of the right temporal lobe. Total dose of the diagnostic X-ray radiated to the fetus was measured 2.5 mrem at the most. The AVM and the hematoma were totally removed successfully at 19 weeks of gestation. A male infant weighing 3180 g was delivered at full term by cesarean section without congenital anomalies and he has been growing up without mental deficits. These results suggest that diagnostic X-ray examination during pregnancy has little risk and that surgical treatment should be given to the mother immediately after the rupture of an AVM if she is in good condition and the gestational date is past 12 weeks.

Adult↗
PubMed1990

[Evaluation of immunotoxicity testings using azathioprine-treated rats: the International Collaborative Immunotoxicity Study (Azathioprine)].

The immunotoxicological effects of azathioprine (AZP) were examined by enhanced histopathological and function tests in the rat which is routinely used in toxicological tests. Male F344 rats were orally administered AZP in doses of 0, 2.5, 12.5 and 25.0 mg/kg/day for 28 days. Reductions in the organ weights of the thymus, spleen, liver, kidney, and testis in a dose-dependent manner were confirmed. Hematological examination revealed a marked decrease in the number of WBCs, which was associated with a decrease in the number of lymphocytes. In the femoral bone marrow, a significant reduction in the total cell number attributed to the decrease in the number of lymphocytes and granulocytes was observed. Histopathologically, atrophy and obfuscation of the corticomedullary junction in the thymus, the decrease of lymphocytes in the thymus and spleen, and the disappearance of germinal centers in the lymph nodes were observed. As for the functional testings, azathioprine treatment did not affect remarkably the PFC number and the NK cell activity per unit spleen cell number. However, the total spleen cell number per spleen was decreased in a dose-dependent manner. Therefore, the total functional activities (PFC and NK) per spleen were decreased. Thus, in the AZP-treated F344 rats, it was shown that the enhanced histopathological tests were useful to evaluate potential risks to the immune system.

Animals↗
PubMed1990

A sandwich-enzyme immunoassay for the quantification of lipoprotein lipase and hepatic triglyceride lipase in human postheparin plasma using monoclonal antibodies to the corresponding enzymes.

We have developed a sandwich-enzyme immunoassay (EIA) for the quantification of lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) in human postheparin plasma (PHP) using monoclonal antibodies (MAbs) directed against the corresponding enzymes purified from human PHP. The sandwich-EIA for LPL was performed by using the combination of two distinct types of anti-LPL MAbs that recognize different epitopes on the LPL molecule. The immunoreactive mass of LPL was specifically measured using a beta-galactosidase-labeled anti-LPL MAb as an enzyme-linked MAb, an anti-LPL MAb linked with the bacterial cell wall as an insolubilized MAb, and purified human PHP-LPL as a standard. The sandwich-EIA for HTGL was carried out by using two distinct anti-HTGL MAbs that recognize different epitopes on HTGL. The limit of detection was 20 ng/ml for LPL and 60 ng/ml for HTGL. Each method yielded a coefficient of variation of less than 6% in intra- and inter-assays, and a high concentration of triglyceride did not interfere with the assays. The average recovery of purified human PHP-LPL and -HTGL added to human PHP samples was 98.8% and 97.5%, respectively. The immunoreactive masses of LPL and HTGL in PHP samples, obtained at a heparin dose of 30 IU/kg, from 34 normolipidemic and 20 hypertriglyceridemic subjects were quantified by the sandwich-EIA. To assess the reliability of the measured mass values, they were compared with the corresponding enzyme activities measured by selective immunoinactivation assay using rabbit anti-human PHP-LPL and -HTGL polyclonal antisera. Both assay methods yielded a highly significant correlation in either normolipidemic (r = 0.945 for LPL; r = 0.932 for HTGL) or hypertriglyceridemic subjects (r = 0.989 for LPL; r = 0.954 for HTGL). The normal mean (+/- SD) level of lipoprotein lipase mass and activity in postheparin plasma was 223 +/- 66 ng/ml and 10.1 +/- 2.9 mumol/h per ml, and that of hepatic triglyceride lipase mass and activity was 1456 +/- 469 ng/ml and 26.4 +/- 8.7 mumol/h per ml, respectively. The present sandwich-enzyme immunoassay methods make it possible to study the molecular nature of LPL and HTGL in PHP from patients with either primary or secondary hyperlipoproteinemia.

Adult↗
PubMed1990

[Clinico-pathological studies on Is, Ip polyps and flat elevations in the large intestine].

We histologically compared 3 types of adenoma and cancer of the large intestine using 620 adenoma specimens (509 Is type lesions, 83 Ip type lesions, and 28 flat type lesions) and 113 specimens of early stage cancer (51 Is type lesions, 39 Ip type lesions, and 23 flat type lesions) obtained during the past 5-year period at our department. More than 90% of the Is and Ip type polyps were adenoma or carcinoma in adenoma while 25.5% of the flat elevations were m or sm carcinoma. Flat elevations even less than 10 mm in diameter were frequently carcinomas (26.3%) compared with the other types (both Is and Ip types, 6.7%), and all of those 10 mm or more in size were carcinomas. The distribution of the flat type early cancers in the large intestine was similar to that of advanced cancer with high percentages of carcinoma at each site compared with the other types. These results suggest that the carcinogenesis and progression of flat type early stage cancer differ from those of the other types.

Adenoma↗
PubMed1990

[A successfully treated case of aortouretric fistula associated with pelvic exenteration].

A 64-year-old man was hospitalized for massive bleeding from the cutaneous ureterostomy. He had undergone pelvic exenteration with the ureterostomy for rectal cancer invading the bladder five months previously and retrograde ureteric catheters were inserted bilaterally into the ureters. An aortography revealed a pseudoaneurysm of the abdominal aorta in the region transversed by the left ureter. He was successfully treated by en bloc resection of the aortoureteric fistula and the left ureter and repair of the aorta by Dacron patchplasty. Left nephrectomy was also performed because of pyelonephritis. He has had no signs of cancer recurrence or graft infection five years after this operation.

Aorta, Abdominal↗
PubMed1989

Purification and characterization of lipoprotein lipase and hepatic triglyceride lipase from human postheparin plasma: production of monospecific antibody to the individual lipase.

Lipoprotein lipase (LPL) and hepatic triglyceride lipase (HTGL) were purified to homogeneity from human postheparin plasma. Molecular, catalytic and immunological properties of the purified enzymes were investigated. The native molecular weights of LPL and HTGL were 67,200 and 65,500, respectively, by gel chromatography. The subunit molecular weights of LPL and HTGL were 60,600 and 64,600, respectively, suggesting that these enzymes are catalytically active in a monomeric form. In addition, the purified LPL and HTGL each gave a single protein band when they were detected as glycoproteins with a probe of concanavalin A. The purified enzyme preparations were free of detectable antithrombin III by Western blot analysis. Catalytic properties of the purified enzymes were examined using triolein-gum arabic emulsion and triolein particles stabilized with phospholipid monolayer as substrates. LPL catalyzed the complete hydrolysis of triolein to free oleate and monooleate in the presence of apolipoprotein C-II. Apparent Km values for triolein and apolipoprotein C-II were 1.0 mM and 0.6 microM, and Vmax was 40.7 mmol/h per mg. HTGL hydrolyzed triolein substrate at a rate much slower than LPL, and produced mainly free oleate with little monooleate. Apparent Km and Vmax values were 2.5 mM and 16.1 mmol/h per mg, respectively. Polyclonal antibodies were developed against the purified LPL and HTGL. The purity and specificity of these antisera were ascertained by immunotitration, Ouchterlony double diffusion and Western blot analyses. The anti-human LPL and anti-human HTGL antiserum specifically reacted with the corresponding either native or denaturated enzyme, indicating that two enzymes were immunologically distinct. We developed an assay system for LPL and HTGL in human PHP by selective immunoprecipitation of each enzyme with the corresponding antiserum.

Antithrombin III↗
PubMed1989

The biologic fate of Dacron double velour vascular prostheses--a clinicopathological study.

Thirty-one Dacron double velour prostheses removed from 16 patients were studied microscopically in order to elucidate the changes they underwent following implantation. The process of incorporation was divided into three phases. In the initial phase, immediately following the implantation, the prostheses became surrounded by a fibrin meshwork. In the organizing phase, which sets in 10 weeks after the implantation, there was an external fibrous capsular formation around the initially fibrin-infiltrated grafts. There was also fibroblastic ingrowth and granulation formation among the interstices and the prostheses showed firm adhesion to the surrounding tissues. One year following the implantation, after most of the luminal surfaces had been covered with collagen tissues, the cellular infiltration subsided and the graft passed into the stable phase. Foreign body giant cells and lymphocytes were seen throughout the study period. These prostheses were then compared with other prostheses which do not have velour structures. The nonvelour grafts showed less adhesion to the surrounding tissues. Microscopically, cellular reaction and collagenous ingrowth were also less. The velour surface thus seems to stimulate granulation ingrowth and to contribute to the firm adhesion of the graft to the surrounding tissues. This firm adhesion enhances resistance to infection and is considered safer in case of suture aneurysm formation.

Aorta↗
PubMed1989

A clinicopathologic study of aneurysm formation of glutaraldehyde-tanned human umbilical vein grafts.

To clarify the process of graft degeneration and aneurysm formation we reviewed the angiographic and pathologic findings of three cases where aneurysms developed in glutaraldehyde-tanned human umbilical vein grafts. Seven aneurysms were detected in these three grafts 4 years after implantation. Six aneurysms originated from the bodies of the grafts and one originated from the factory-created anastomosis required for fabrication. Wrinkling and segmentation of the dilated graft documented by arteriography corresponded to mural dissection of the graft wall. Large protrusions near the aneurysms were revealed to be the transmurally dissected graft walls. At the site of dissection, blood escaped through the surrounding mesh of the graft to form a preaneurysmal change. Two aneurysms developed without breakdown of the outer mesh. The aneurysm of factory-created sutures was caused by tearing of the graft wall. Degeneration of human umbilical vein grafts, which appears to ensue inevitably with the passage of time after implantation, leads to the tear of the graft wall and transmural dissection to form aneurysm. In our department, candidates for human umbilical vein graft implantation have recently been restricted to the patients whose life expectancy is limited to only a few years because of the risk of aneurysm formation.

Aged↗
PubMed1989

Computer-aided three-dimensional reconstruction: a method of measuring temporal bone structures including the length of the cochlea.

To visualize the three-dimensional (3-D) shapes of structures in the temporal bone from histologic sections, we developed computer software to create computer-generated 3-D images from two-dimensional (2-D) materials. Using those images, we have been able to measure these structures in three dimensions. This means that quantitative 3-D measurements can be performed regardless of the angle at which the specimen was cut. This report describes this method for 3-D reconstruction and measurement and discusses its implications. For instance, in addition to showing the 3-D shape of the cochlea from different angles, we have been able to measure the length of the cochlea and have shown that measurements made by use of the conventional 2-D graphic reconstruction method can be distorted considerably by variations in cutting angle of the specimen.

Cochlea↗
PubMed1989

Computer-aided three-dimensional reconstruction and measurement of the round window and its membrane.

This study was performed to clarify the complex three-dimensional shape of the round window and its membrane, and to measure these structures by using the computer-aided three-dimensional reconstruction method we developed. The equipment used included a personal computer, a high-resolution, 14-inch color monitor, and a digitizer. Materials consisted of five normal temporal bones obtained from five individuals with negative otologic histories who had been 5 months and 14, 15, 18, and 59 years old at death. Round window membranes were found to be convex to the middle ear side when viewed in the coronal plane, but to be concave when viewed in the sagittal plane; thus the membrane in most cases seemed to be shaped like a saddle, tapered toward the vestibular end. The average maximal diameter, sagittal length, horizontal width, and surface area of the round window were 2.32 +/- 0.19 mm, 2.08 +/- 0.22 mm, 1.76 +/- 0.10 mm, and 2.70 +/- 0.43 mm2, respectively. The average surface area of the round window membrane was 2.98 +/- 0.43 mm2.

Adolescent↗
PubMed1989

Three-dimensional computer reconstruction of a temporal bone.

The complexities of the temporal bone and the critical inter-relationships among its key structures can be simplified with three-dimensional computer-assisted reconstruction. Knowledge of the topography of these structures and their mutual relationships in essential in any surgical approach to the temporal bone. Sixty sagittal histologic sections of a normal left temporal bone were examined. Each section, 30 microns in thickness, was optically enlarged. Segments representing the facial nerve, internal carotid artery, and inner ear structures from individual slides were traced and data were entered into a computer. A personal computer was used for data processing and analysis. Graphic software developed in our laboratory generated images with x-y-z coordinates that could be rotated in any plane. The high resolution of the computer graphics system, combined with the precision of histologic sections, permitted study of the critical three-dimensional anatomic relationships among essential intratemporal bone structures. The capability of reproducing individual and joint images of the intratemporal bone structures and viewing them from all surgical angles gives skull base and otologic surgeons important topographic guidance. Accurate spatial measurements of temporal bone anatomy are now possible with the application of computer graphic technology.

Carotid Artery, Internal↗
PubMed1989

Computer-aided three-dimensional reconstruction and measurement of the round window niche.

The goal of this study was to clarify the three-dimensional shape of the round window niche and to measure this structure three-dimensionally using the computer-aided reconstruction method we developed. The equipment used in this study included a personal computer (NEC 98-XA), a high-resolution 14-inch color CRT, a digitizer (Hitachi HDG-1111), and a printer. We studied five normal temporal bones obtained from five individuals with negative otologic histories, who had been 5 months and 14, 15, 18, and 59 years old at death. In each case the round window niche was located posteroinferior to the round window. The round window niches had wide openings to the middle ear cavity that became narrower near the aperture; thus, the round window niche seemed to be shaped like a pouch. The maximal diameter of the round window niche was 2.98 +/- 0.23 mm. The shortest distance between the aperture of the round window niche and the margin of the round window was 0.66 +/- 0.16 mm. The volume of the round window niche, on average, was 4.65 +/- 0.67 mm3. The volume of the round window niche was found to be correlated with the area of the round window.

Adolescent↗