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Biomedical subjects

H Obata

Publications and source records attributed to H Obata.

At least 163 records · Page 9Linked to original sources
PubMed1991

Effects of regression of left ventricular hypertrophy following atenolol or bunazosin therapy on ischemic cardiac function and myocardial metabolism in spontaneously hypertensive rats.

The effects of regression of left ventricular hypertrophy following atenolol and bunazosin therapy on ischemic cardiac function and myocardial metabolism in spontaneously hypertensive rats (SHR) were studied. Atenolol (50 mg/kg/day) and bunazosin (5 mg/kg/day) were administered to SHR from 19 to 26 weeks of age, whereas tap water was given to control SHR and normotensive Wistar-Kyoto rats (WKY). Both atenolol and bunazosin significantly decreased arterial blood pressure and significantly decelerated the increase in left ventricular weight in SHR. At the end of the long-term treatment, hearts were removed and perfused by the working heart technique for 15 min, and then global ischemia was induced for either 10 or 30 min. The ischemic heart was reperfused for 30 min. The pressure-rate product and the extent of recovery of the coronary flow after reperfusion following 30 min of ischemia in the bunazosin-treated SHR were significantly higher than those in the control SHR and the atenolol-treated SHR. The levels of adenosine triphosphate (ATP), creatine phosphate (CrP), and energy charge potential in the SHR heart reperfused after 30 min of ischemia were significantly lower than those in the reperfused WKY. Both atenolol and bunazosin improved the restoration of ATP and CrP in SHR after reperfusion following 30 min of ischemia. In conclusion, antihypertensive therapy with either atenolol or bunazosin was effective in preventing cardiac hypertrophy and ischemic damage caused by different mechanisms. Factors resulting from stimulation of the cardiac alpha 1 adrenoceptor may play an important role in the development of hypertensive cardiac hypertrophy, just as factors resulting from stimulation of the beta 1-adrenoceptor do.

Adenosine Diphosphate↗
PubMed1991

[Multiple pulmonary metastasis from histologically benign giant cell tumor of the right radial olecranon].

An unusual case of a benign giant cell tumor of bone with pulmonary metastasis is reported. A 23-year-old man had a painful tumor in the right radial olecranon that proved to be a histologically benign giant cell tumor. Curettage and bone-grafting were performed, but the tumor recurred twice, 8 months and 20 months after initial treatment. Histological examination of biopsy materials from the recurring tumor showed typical benign giant cell tumors. Five years later, wedge resections were performed for bilateral pulmonary nodules, which had been detected by chance. The pulmonary nodules turned out to be histologically similar to the primary tumor of the olecranon. Almost 7 years later, he was asymptomatic and the chest radiograph was clear, and there was no local recurrence of the lesion.

Adult↗
PubMed1991

[The way of submucosal invasion of superficial sm cancers].

Nineteen superficial sm cancers were studied as for their way of submucosal invasion. The materials were obtained either by colonoscopic polypectomy or by surgical operation. The following were concluded: 1. The ways of submucosal invasion can be classified into three. There is a special type of superficial early cancer which penetrate the mucosal muscle at one point and reaches the deeper layer linearly or show expansive growth at the submucosal layer. 2. The speed of submucosal invasion is either earlier (at the size around 5 mm), or slower (over 15 mm). 3. There are no significant difference in the way of submucosal invasion between IIa and IIc subclasses of superficial early cancers. That is one supporting evidence that there is no fundamental difference among subclasses of shapes of superficial early cancers. 4. One reason why the diagnosis of superficial cancers is difficult is that not a few superficial cancers undergo early morphological change (to sessile form) due to massive submucosal invasion.

Aged↗
PubMed1991

Corneal endothelial cell damage in penetrating keratoplasty.

Fifty-eight corneal grafts were examined by specular microscopy to determine the corneal endothelial cell damage following penetrating keratoplasty. The average postoperative follow-up period was 10.1 months. The cell density decreased continuously during the observation period, and the endothelial cell loss of the central area of the cornea in all the cases averaged 10.4% at two weeks after the surgery, 16.0% at one month, 33.0% at three months, 39.4% at six months, and 48.2% at one year. However, the cell loss in the keratoconus group averaged -1.9, 1.2, 9.9, 30.6 and 33.4% for the corresponding postoperative periods. The cell loss in the bullous keratopathy eyes showed higher values compared to those in the keratoconus and the corneal leukoma eyes. It was concluded that cell loss in penetrating keratoplasty during the first postoperative year depends on the host diseases.

Adolescent↗
PubMed1991

HLA-DR expression on the microvasculature of portal tracts in idiopathic portal hypertension. Immunohistochemical characteristics and relation to portal phlebosclerosis.

We recently reported that HLA-DR antigen was expressed on the microvasculature of portal tracts more frequently in idiopathic portal hypertension (IPH) than in normal livers or in other hepatic diseases, and that this HLA-DR expression may be involved in the development of the portal venopathy characteristic of IPH. The present study was performed to evaluate the relationship between the HLA-DR expression and portal tract lesions, as well as to investigate the immunohistochemical characteristics of the HLA-DR-positive microvasculature using liver wedge biopsy specimens obtained from 32 patients with IPH. According to the degree of phlebosclerosis of the portal veins, the portal tracts were divided into three groups: mild, moderate, and severe. The microvasculature in portal tracts was positive for HLA-DR in 21 (66%) of the 32 specimens and in 133 (44%) of 302 portal tracts. In the 21 specimens, there was no significant difference in the prevalence of HLA-DR-positive microvasculature among the three groups: it occurred in 57 (66%) of 86 portal tracts in the mild group, 53 (61%) of 87 portal tracts in the moderate group, and 23 (49%) of 47 portal tracts in the severe group. The HLA-DR-positive microvasculature was positive for type IV collagen and receptors of Ulex europaeus lectin I, suggesting that HLA-DR-positive microvessels are blood vessels. These findings suggest that HLA-DR antigen is already expressed on portal microvessels in the incipient stage of IPH, and that HLA-DR expression persists during the progression of portal phlebosclerosis. The HLA-DR expression may be an initiating factor leading to immunologic assault on portal microvessels in IPH.

Aged↗
PubMed1991

Expression of HLA-DR antigen on hepatic vascular endothelial cells in idiopathic portal hypertension.

Immunologic abnormalities have been reported in idiopathic portal hypertension, though the exact immunologic mechanism(s) leading to various portal venopathies in this disease remain unsettled. Recently, aberrant expression of HLA-DR antigen on target cells has been noted in the organ-specific autoimmune diseases. In this study the expression of HLA-DR antigen on the hepatic vasculature was surveyed immunohistochemically in idiopathic portal hypertension (n = 36) and in control livers: normal livers (n = 27), chronic active hepatitis (n = 35) and cirrhosis (n = 21). Endothelial cells of hepatic veins and hepatic arteries occasionally expressed HLA-DR antigen, and there was no difference in the expression between idiopathic portal hypertension and controls. Endothelial cells of the main portal vein, within the small and medium-sized portal tract, did not express HLA-DR antigen in idiopathic portal hypertension and controls. By contrast, endothelial cells of the smaller venous radicles, including inlet venules in these portal tracts other than the main portal vein, more frequently expressed HLA-DR antigen in idiopathic portal hypertension (78%) than in chronic active hepatitis (26%), cirrhosis (29%) and normal liver (15%). These data raise the possibility that the smaller venous radicles in the small and medium-sized portal tracts are targets of immunologic attack in idiopathic portal hypertension.

Adult↗
PubMed1991

[Evaluation of patient-oriented exercise tolerance based on symptoms of patients with heart failure].

Exercise tolerance is one of the most important factors when evaluating patients with heart failure, because it is closely related to their symptoms, Treadmill or ergometer test is usually used to evaluate exercise tolerance. But these tests are painful and sometimes dangerous to the seriously-ill patients. Further exercise tolerance tests reflect the exercise capacity under unusual conditions, which differs greatly from daily activities. So it is very questionable whether we can evaluate actual exercise capacity by exercise tolerance tests. Therefore I devised my own exercise tolerance classification, with 10 Grades according to the symptoms felt during walking. I used this classification for patients with heart failure, and investigated its utility. I studied the correlation between the new classification and the symptom-limited exercise duration in 18 patients, and between the classification and anaerobic threshold in 12 patients. I got good correlation in each of them; (r = 0.842,p less than 0.001) and (r = 0.806, p less than 0.01). The classification also correlated with pulmonary wedge pressure (r = -0.778, p less than 0.05), but it had no correlation with other hemodynamic and morphological parameters. The classification also reflected therapeutic efficacy of heart failure. These results indicate that the new classification is useful in evaluating exercise tolerance without imposing any discomfort on patients with heart failure.

Adolescent↗
PubMed1991

[Experimental evaluation of the reliance of coronary sinus blood flow (CSF) and great cardiac vein blood flow (GCVF) measured by local thermodilution method].

A closed circuit was made to evaluate the reliance of coronary sinus blood flow (CSF) and great cardiac vein blood flow (GCVF) measured by local thermodilution method using multi-thermister catheter. The circuit consists of four parts: a constant-temperature water bath, a reservoir, a rotary pump and a polyethylene tube with a cock. Using this circuit and thermodilution catheters, flow rate was measured under various conditions. Measurements were repeated in changing injection rate of indicator, thermister interval of the catheter, diameter of the polyethylene tube and temperature difference between the room and the water bath. Indicator injection rate and thermister interval were important factors in flow rate measurement. Measured data and real flow were well correlated until 300 ml/min in injection rate of 40-50 ml/min. Other factors did not significantly influence the flow measurement. These results indicate that local thermodilution method is reliable if only injection rate of indicator and thermister interval are suitably settled.

Body Temperature↗
PubMed1990

[An autopsy case of acute interstitial pneumonia].

An autopsy case of a 77-year-old male with acute interstitial pneumonia (AIP) is reported. The patient died of respiratory failure in the extremely rapid course of 8 days. The histogenesis of the thickening of the alveolar wall and the intraluminal lesions were noticed. Incorporation of the hyaline membrane as well as the intraseptal edema and septal cell proliferation played an important role in the fibrous thickening of the alveolar wall. The intraluminal granulation tissue was observed in the alveolar space and the alveolar duct, often extending into the respiratory bronchioles. Intraluminal granulation tissues in the alveoli frequently had the appearance of intraluminal buds of mesenchymal cells, so-called Masson's bodies, and there was little remodeling of pulmonary structures in this case. These findings suggest an acute, diffuse and severe damage of the peripheral respiratory tract and are consistent with bronchiolitis obliterans with classical interstitial pneumonia (BIP) by Liebow and AIP by Katzenstein. This patient had suffered from suspected "Bronchiolitis obliterans organizing pneumonia" (BOOP) one and half years ago. The relationship between AIP, BIP and BOOP is discussed.

Aged↗
PubMed1990

Transcatheter arterial injection of autologous lymphokine-activated killer (LAK) cells into patients with liver cancers.

We studied the effect of transcatheter arterial injection of lymphokine-activated killer (LAK) cells in conjunction with interleukin-2 on 13 patients with liver cancers, 9 primary hepatocellular carcinomas (HCC), and 4 metastatic liver cancers. Based on the fact that the LAK-cell phenomenon was observed to exist equally in these patients as in healthy controls, an injection of autologous LAK cells into these patients was performed. Of 13 patients receiving LAK cells plus interleukin-2, one had a partial response and three had minor responses. The response duration of this "partial-response" patient was around 6 months after the LAK-cell injection. Simultaneously, a reduction of serum AFP level was found in six of eight HCC patients. One patient having a minor response after receiving this therapy had severe side effects, such as dyspnea and hypotension. The others had only a transient fever which was easy to control by medication. Thus the present study indicates that a measurable tumor regression and a reduction of serum AFP level are observed in some liver cancers after undergoing this therapy.

Adult↗
PubMed1990

Two new potent inhibitors of xanthine oxidase from leaves of Perilla frutescens Britton var. acuta Kudo.

A known and a new caffeic ester (1 and 2), new inhibitors of xanthine oxidase (XO), were isolated from leaves of Perilla frutescens var. acuta and their structures have been established as (Z,E)-2-(3,4-dihydroxyphenyl)ethenyl ester (1) and (Z,E)-2-(3,5-dihydroxyphenyl)ethenyl ester (2) of 3-(3,4-dihydroxyphenyl)-2-propenoic acid, respectively, based on detailed spectral studies, including 2D COSY, long range COSY, difference NOE, etc. Both caffeic esters strongly inhibited XO in vitro and especially, the inhibition by 1 was as potent as that by allopurinol. The inhibition mode of 1 was also shown to be non-competitive.

Plants, Medicinal↗
PubMed1990

Effect of captopril on congestive heart failure.

1) Captopril was orally administered in a dose of 12.5 mg to 12 patients with congestive heart failure to follow changes in its blood concentration and determine changes in clinical test values. 2) The blood concentration of captopril reached its peak in 2 h after medication, the mean value being 274 ng/ml and the half-life 3.16 h. The Tmax and T1/2 were found to be extended as compared with those of normal humans and hypertensive patients that had been reported. No significant differences were noted between Group I of mild cases and Group II of serious cases. 3) Following administration of captopril, a rise in angiotensin I and renin activity and a reduction in aldosterone were noted. These were found to be correlated or inversely correlated with the changes in the blood concentration of captopril. Greater changes were noted in Group II than in Group I. All clinical test values in each group tended to return to the control value 6h after the administration.

Aldosterone↗
PubMed1990

Response of isolated perfused heart to ischemia after long-term treatment of spontaneously hypertensive rats with diltiazem.

The effects of long-term treatment with diltiazem on the heart in normotensive (WKY) and spontaneously hypertensive rats (SHR) were studied. Diltiazem was added to the drinking fluid (900 mg/liter) and given ad libitum from 19 to 26 weeks of age, whereas tap water was given to the control animals. Although diltiazem did not decrease blood pressure in SHR, it decelerated the increase in their left ventricular weight (p less than 0.01). Hearts were removed and perfused by the working heart technique for 15 min, and then global ischemia was induced for either 10 or 30 min. The ischemic heart was reperfused for 30 min. The extent of recovery of coronary flow after reperfusion, following 30 min of ischemia in the diltiazem-treated SHR, was higher than that in the control SHR (p less than 0.01). The levels of adenosine triphosphate (ATP), creatine phosphate (CrP), and energy charge potential in the SHR heart reperfused after 30 min of ischemia were lower than those in the reperfused WKY heart (p less than 0.01, respectively). Diltiazem improved the restoration of ATP and CrP and prevented the decrease in energy charge potential in SHR after reperfusion following 30 min of ischemia (p less than 0.01, respectively). In conclusion, long-term treatment of SHR with diltiazem may protect the myocardium when myocardial ischemia occurs.

Adenine Nucleotides↗
PubMed1989

A case of biliary cystadenocarcinoma with morphologic and histochemical features of hepatocytes.

A case of biliary cystadenocarcinoma is presented in which the lesion seemed to partially differentiate into hepatocellular carcinoma. This patient had a cystic tumor in the left lobe of the liver, the interior being filled with papillary tumors. Histologic examination disclosed papillary growth of columnar tumor cells, together with tumor cells akin to hepatocytes (they had a distinct cell boundary, nuclear membrane, and nucleolus) showing a cobblestone appearance in some areas. Electron microscopic examination of this area showed bile canalicular structures. Histochemically, the tissue stained positively with the Luna-Ishak canalicular (LIC) technique; periodic acid-Schiff (PAS) staining demonstrated coexisting glycogen granulo-positive cells and mucus-producing cells. Thus, in this biliary cystadenocarcinoma, some tumor cells demonstrated the morphologic and histochemical features of hepatocytes.

Aged↗
PubMed1989

Follow-up after polypectomy of colorectal adenomas. The importance of total colonoscopy.

Five hundred eighty-two patients with colorectal adenomas or early cancers were polypectomized from 1974 to 1985. In 100 patients, total colonoscopy was performed more than twice after the initial polypectomies. These patients were divided into three groups: group A patients underwent total colonoscopy at 1-year intervals; group B patients underwent total colonoscopy at 2-year intervals, group C patients underwent total colonoscopy at 3-year or more than 3-year intervals. The frequency and location of newly developed adenomas were investigated. The detection rate for new adenomas was 13% in group A and 50% in group B; thus, there was a significant difference between group A and group B (P less than 0.01). The transverse colon is the only segment where the topological proportion of newly developed adenomas increased in comparison with that of index adenomas (P less than 0.05). The detection rate for new adenomas was significantly higher in patients who had carcinoma in situ at the time of initial polypectomy (P less than 0.05). Questionnaires about colonoscopy and colonic adenomas were therefore mailed to the patients who were lost to follow-up after the polypectomy.

Colonic Polyps↗
PubMed1989

Evaluation of endoscopic ultrasonography for gastric tumors and presentation of three-dimensional display of endoscopic ultrasonography.

We have studied the usefulness of endoscopic ultrasonography (EUS) for: (1) differentiation between extragastric mural compression (EGMC) and submucosal tumors (SMT); (2) qualitative assessment of these lesions; (3) diagnosis of serosal invasion by malignant gastric tumors; (4) presentation of three-dimensional display of EUS findings. A total of 103 patients with submucosal lesions protruding into the gastric lumen on endoscopy were examined. Differentiation between EGMC and SMT could be made by EUS in all cases. Qualitative assessment of these lesions was made by observing their EUS findings, i.e. their internal and marginal echo pattern and their location in the gastric layers. The correct diagnosis was made in 88% (23/26) of EGMC. Of 50 patients with SMT, comprising myogenic tumor (32), aberrant pancreas (8), lipoma (3), gastric cyst (4) and malignant lymphoma (elevated type; 3), differentiation between malignant and benign myogenic tumors was impossible by EUS alone. In addition, 48 patients with advanced gastric cancer and malignant lymphoma were examined. Invasion to the serosal surface was diagnosed as interruption of the fifth layer of the gastric wall. Invasion to other organs was diagnosed by interruption and fusion of the fifth layer into the border of the adjacent structure. Serosal invasion was diagnosed accurately in 65% of 48 patients. Microscopic invasion was difficult to diagnose, and gastric stenosis by tumor was an obstacle to adequate scanning. EUS can be valuable in the differential diagnosis between EGMC and SMT and in the qualitative diagnosis of gastric lesions. It is also effective in detecting serosal invasion by gastric malignant tumors. Three-dimensional display of pathological lesions is new in EUS.(ABSTRACT TRUNCATED AT 250 WORDS)

Computer Graphics↗
PubMed1989

Frequency and types of point mutation at the 12th codon of the c-Ki-ras gene found in pancreatic cancers from Japanese patients.

Point mutations at the 12th codon of c-Ki-ras in pancreatic cancer from Japanese patients were examined using the polymerase chain reaction, followed by cloning of the amplified gene fragments in pTZ phagemid and nucleotide sequence determination. The frequency of the point mutations found in the tumors was quite high (75%). The mutation most frequently detected was a G---A transition at the second position of codon 12 (GGT---GAT), but other types of mutations such as GGT----GTT and GGT----CGT were also found. In one case, silent mutation of GGT to GGC was detected in addition to the frequent mutation of GGT to GAT. These observations suggest that the 12th codon of pancreatic c-Ki-ras is highly mutatable.

Adenocarcinoma↗