Biomedical subjects

Y Doi

Publications and source records attributed to Y Doi.

At least 343 records · Page 19Linked to original sources

PubMed1992

Sequential appearance of fibronectin, collagen and elastin during fatty streak initiation and maturation in hypercholesterolemic fat-fed rabbits.

To elucidate whether tissue fibronectin increases in the early stages of atherogenesis induced by hypercholesterolemia without mechanical trauma, we investigated sequential changes in the distribution of tissue fibronectin during fatty streak initiation and maturation in the aortas of hypercholesterolemic fat-fed rabbits. The presence of fibronectin was examined on immunoperoxidase stained tissue specimens with the aid of a microscope-photometric technique. Twenty male albino rabbits were used. Cholesterol supplemented chow (1%) was given for 4 weeks (n = 6), 8 (n = 5) or 14 weeks (n = 5). A membrane-like layer positive for fibronectin was observed along the endothelium in the normal aorta. After 4 weeks of the cholesterol-feeding, fatty streaks were initiated in the intima, where fibronectin was more densely accumulated than the normal intima. After 8 weeks of the cholesterol-feeding, fatty streaks were expanding, associated with the dense staining for fibronectin. After 14 weeks, fibronectin was still concentrated in the endothelial layer and also in the superficial areas of the thickened intima, but decreased in the deep areas of the thickened intima where collagen and elastin appeared as bundles. The photometric data of fibronectin supported these visual observations. Thus, fibronectin appeared early and disappeared later in the intima during the process of fatty streak initiation and maturation. These findings suggest that in hypercholesterolemia without mechanical endothelial injury, fibronectin may play an important role in an early process of atherogenesis.

Animals↗

PubMed1992

Negative washout rate of myocardial thallium-201--a specific marker for high grade coronary artery narrowing.

A decline is usually observed in the myocardial uptake of thallium-201 in delayed imaging compared with initial imaging. In patients with severe coronary artery disease (CAD), the uptake is sometimes higher in the delayed than in the initial imaging, which is expressed as negative washout rate. To evaluate the diagnostic implications of this negative washout rate the findings of dipyridamole thallium scintigraphy in 582 patients with coronary artery disease were evaluated. The negative washout rate was present in 201 of 582 patients (35%). It had a significant association with high grade coronary artery narrowing of > or = 90%. Sensitivity in detecting patients with this high grade narrowing by negative washout rate was 48%, its specificity was 93%, and its positive predictive value was 94%. Sensitivity to detect individual coronary artery narrowing of > or = 90% did not decrease according to the extent of CAD, with the highest detection in the left anterior descending coronary artery and the lowest in the left circumflex coronary artery. Since patients with high grade coronary narrowing often require coronary intervention, the results of this study suggest the diagnostic importance of negative washout rate in the identification of the particular subset of patients with CAD.

Adult↗

PubMed1992

Production of active and inactive renin by adrenal explant cultures and the existence of a prorenin activating enzyme in the adrenal gland.

We previously demonstrated high levels of inactive renin (IR) in nephrectomized rat plasma which provided evidence for extra-renal sources of IR. However, the sources of IR were unknown. This study examined whether the adrenal gland is capable of producing active renin (AR) and IR, using explants of adrenal capsules (glomerulosa portions) from control and nephrectomized (Nepex) rats. Explants from both control and Nepex rats produced large quantities of IR and small quantities of AR. The productions of both IR and AR in Nepex rats were significantly greater than in control rats. High potassium culture medium markedly increased IR and slightly, but significantly, enhanced AR in both control and Nepex rats. On the other hand, sodium had little effect on either IR or AR. A renin-angiotensin system has been reported in the adrenal gland. Recently, a prorenin activating enzyme was demonstrated in the kidney and the aortic wall. The next study was performed to demonstrate the existence of a prorenin activating enzyme in the adrenal gland, using inactive renin from culture medium from Nepex rat explants as the substrate. A 26 KD component in adrenal zona glomerulosa tissues isolated by Sephacryl S-200 column chromatography, converted IR to AR in IR rich medium. The pH optimum for prorenin activation by the enzyme was 6.5. Inhibitor studies indicate that this enzyme is a serine protease. These data suggest that (1) the adrenal gland is an extra-renal source of inactive renin and (2) a prorenin activating enzyme exists in the adrenal gland.

Adrenal Glands↗

PubMed1992

[Prognosis of asymptomatic elderly patients with aortic stenosis].

To elucidate the prognosis of elderly patients with asymptomatic aortic stenosis (AS) and to assess the timing of aortic valve replacement (AVR), 21 asymptomatic patients (8 men, 13 women, mean age: 75 +/- 8 years (54-89 years)), who had Doppler echocardiographic evidence of a significant aortic pressure gradient of greater than 40 mmHg (mean gradient: 75 +/- 31 mmHg), were followed for 33 +/- 10 months. During the follow-up, there were 4 cardiac events (2 cardiac deaths, 2 late AVRs), and 2 non-cardiac deaths (cerebro-vascular accidents). Among 15 survivors, 13 patients were in NYHA class I--II, and the remaining 2 patients were found to have malignant disease. Compared to the 17 patients without cardiac events, those with cardiac events had significantly larger CTR (58 +/- 6% vs. 53 +/- 3%; p less than 0.01), although there were no significant difference in electrocardiographic LVH, echocardiographic LV mass, and Doppler pressure gradient between the two groups. The prevalence of the development of cardiac symptoms during the follow-up was not high (12%) in patients without cardiac events. Among 4 patients with cardiac events, one patient who was 89 years-old at diagnosis died of heart failure, one patient had fatal myocardial infarction which seemed to be unrelated to AS, and two patients had successful late AVR because of new heart failure. The low incidence of fatal cardiac events in asymptomatic patients with aortic stenosis and the relatively high possibility of developing non-cardiac events in elderly patients indicate that the decision-making for AVR should not be solely based upon the pressure gradient detected by Doppler echocardiography.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

[Gennai Hiraga and Bosho: with special reference to the manuscripts kept by the Suzukis, Izu].

Bosho is one of the important mineral drugs in the Edo era. Gennai Hiraga (1728-1779) gave a lot of space to the item of natural product Bokusho in his book "Butsurui-hinshitsu" (1763). Gennai made bosho from bokusho that was deposited at spring in Kamifunabara is little known to us except "Butsurui-hinshitsu". In Kamifunabara, we got an opportunity to survey the manuscripts kept by the Suzukis, which show Gennai's visit and activities there. The object of this paper is to introduce the manuscripts kept by the Suzukis and also to consider widely the knowledge of Gennai and his teacher Ransui Tamura (1718-1776) concerning bosho and related materials.

History, 18th Century↗

PubMed1992

[Hemodynamic difference accounted for the orientation of a Björk-Shiley mitral prosthesis: a color Doppler echocardiographic study].

To determine whether the orientation of the major orifice of a mitral tilting disc prosthesis affects hemodynamics, intracavitary blood flow patterns were studied in 45 patients with well-functioning Björk-Shiley mitral prosthesis using color Doppler flow imaging. The major orifice was oriented towards the septum in 23 patients (12 men, 11 women, age 58 +/- 11 years; group S), and towards the posterior wall in 22 patients (8 men, 14 women, age 55 +/- 9 years; group P). 1) The left ventricular end-diastolic dimensions (S: 4.8 +/- 0.9 cm, P: 5.2 +/- 1.0 cm), end-systolic dimensions (S: 3.6 +/- 0.9 cm, P: 3.8 +/- 1.2 cm), and left atrial dimensions (S: 5.0 +/- 1.0 cm, P: 4.7 +/- 0.9 cm) did not differ significantly between the 2 groups. 2) The peak mitral flow velocities (S: 1.43 +/- 0.38 m/sec, P: 1.43 +/- 0.27 m/sec), pressure gradients (S: 8.5 +/- 4.0 mmHg, P: 8.4 +/- 3.1 mmHg), and pressure half-times (S: 94.0 +/- 19.0 msec, P: 86.5 +/- 21.7 msec) did not differ significantly between the 2 groups. 3) Although mitral regurgitation was detected in 8 patients (35%) in the S group and in 2 patients (9%) in the P group, hemodynamically significant regurgitation was detected in only 4 patients in the S group (3 mild, one moderate). 4) The patients in the S group had reversed intracavitary blood flow; mitral flow was first directed towards the left ventricular outflow tract during diastole, while the outflow pattern was displaced into the left ventricular inflow tract.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗

PubMed1992

[Assessment of prognosis of old myocardial infarction].

In an attempt to predict high risk myocardial infarction, we studied 201 patients with Q wave infarction with dipyridamole-loading thallium-201 myocardial perfusion scintigraphy (D-MPS), left ventriculography, coronary angiography and treadmill exercise testing. The results of these tests were related to the use of initial PTCA or CABG, and the occurrence of cardiac deaths and nonfatal cardiac events during a mean follow-up period of 39 months. Three high risk parameters were identified by D-MPS; partial redistribution, diffuse slow washout, and extensive fixed defects. The patients were categorized into 3 groups according to the numbers of high risk parameters: group A (n = 50), patients with 2 or more high risk parameters; group B (n = 95), patients with one high risk parameter; group C (n = 56), patients without a high risk parameter. The prevalence of 3-, 2-, and one- or insignificant vessel disease was 72, 20 and 8% in group A, 15, 16, and 69% in group B, and 5, 13 and 82% in group C, respectively. Initial PTCA or CABG was performed in 42% of the patients in group A, 5% of the patients in group B, and 2% of the patients in group C. Among medically-treated patients, cardiac deaths occurred in 31% in group A, 4% in group B, and in none in group C. Nonfatal cardiac events occurred in 24, 12, and 4%, respectively. Coronary angiography revealed 3-vessel disease in 53 patients, 2-vessel disease in 32, and one-vessel disease or insignificant lesions in 116 patients. Initial PTCA or CABG was performed in 45% of the patients with 3-vessel disease, 6% of those with 2-vessel disease and 1% of those with one-vessel disease. Among medically-treated patients, cardiac deaths occurred in 31% with 3-vessel disease, 7% with 2-vessel disease, and in 2% with one-vessel disease. Nonfatal cardiac events occurred in 17, 10, and 3%, respectively.

Adult↗

PubMed1992

Effects of lisinopril and low-dose trichlormethiazide on lipoprotein metabolism in patients with mild to moderate hypertension.

Fifty-six hypertensive patients were recruited to participate in a 12 week, randomised, multicentre trial to compare the effects of lisinopril (n = 31) and low-dose trichlormethiazide (n = 25) administration on blood pressure and lipoprotein metabolism. Both systolic and diastolic BPs decreased significantly after administration of lisinopril (5-40mg/day, mean dose 11 mg/day) and trichlormethiazide (2.0-4.0 mg/day, mean dose 2.2 mg/day). There were no significant changes in lipids, lipoproteins or apolipoproteins with either drug for 12 weeks and no significant differences between the two drugs for these parameters. It is concluded that lisinopril and low-dose trichlormethiazide administration are effective antihypertensive measures without any adverse effects after 12 weeks on lipoprotein metabolism in patients with mild to moderate essential hypertension.

Adult↗

PubMed1992

[A family of Marchesani syndrome with mitral valve prolapse and anuloaortic ectasia].

Marchesani syndrome consists of short statue, small spherical lens, glaucoma and brachydactyly, which are manifestations of hyperplastic connective tissue disease in systemic organs of mesodermal origin (Marchesani 1939). Among nearly 200 cases of Marchesani syndrome reported in the ophthalmology field, none has shown cardiac manifestations which typically characterize Marfan syndrome caused by hypoplastic connective tissue disorders. We experienced 2 cases which met the diagnosis of Marchesani syndrome and yet showed annuloaortic ectasia and mitral valve prolapse. A 30-year-old man and a 26-year-old woman who are siblings suffered from manifested brachydactyly, spherophakia, glaucoma and cardiac involvements. Their parents are in consanguinity. These unprecedented cases with mixed manifestations provide the evidence of possible gene-crossing between these 2 dystrophic mesodermal disorders.

Adult↗

PubMed1992

[Evaluation of left ventricular relaxation by mitral regurgitant curve].

To examine whether left ventricular (LV) isovolumic relaxation can be assessed noninvasively using a continuous-wave Doppler technique, we compared Doppler-determined parameters derived from mitral regurgitation (MR) velocity curve with micromanometer-derived indices of LV relaxation, peak negative dP/dt and tau, in 9 patients with MR (5 with dilated cardiomyopathy, 2 with old myocardial infarction and 2 with rheumatic MR). The rate of LV pressure decay (delta P/delta t) at aortic valve closure was calculated from the recordings of MR jet velocities based on the simplified Bernoulli equation. The time constant of LV pressure decay (tD) was determined as the time from the aortic valve closure to the point where the velocity declined by (1/e)1/2. Doppler-determined delta P/delta t correlated well with hemodynamic peak negative dP/dt (r = 0.97, p < 0.001), and tD with hemodynamic tau (r = 0.89, p < 0.005). Thus, we concluded that left ventricular isovolumic relaxation can be noninvasively assessed with a continuous-wave Doppler technique in the presence of mitral regurgitation.

Blood Flow Velocity↗

PubMed1992

Role of multipotent fibroblasts in the healing colonic mucosa of rabbits. Ultrastructural and immunocytochemical study.

Light- and electron microscopy and immunocytochemistry were used to study the healing colonic mucosa of rabbits after experimental excision. Between 3 and 5 days, abundant young fibroblasts which retained many features of mesenchymal cells invaded the growing capillaries into the loose connective tissue of the healing colonic mucosa. Our electron microscopy revealed the transformation of these young fibroblasts into smooth muscle cells, into histiocyte-like cells involved in phagocytotic activity, and into vasoformative cells incorporated into the growing capillaries. The mitotic proliferation of pre-existing smooth muscle cells at the ulcer margin did not seem to be the major reason for re-establishment of the muscular tissue. The present immunocytochemistry revealed an active production of fibronectin in rough endoplasmic reticulum in the young fibroblasts. This may mean that this glycoprotein is involved in the re-establishment of both connective and muscular tissues by enhancement of adhesion and chemoattractant activities of such cells. In addition, the immunoreaction of endothelial cells of the growing capillaries suggests a role of this glycoprotein in the acceleration of the neocapillarization.

Animals↗

PubMed1992

[A case of sarcoidosis associated with Sjögren's syndrome].

A 49-year-old woman, who has had a past history of Raynaud's phenomenon since 1981, dry mouth since 1987 and dry eyes since 1990, was admitted to our hospital complaining of general fatigue, bilateral gonalgia, and shortness of breath in April 1991. Physical examinations revealed bilateral parotid gland enlargement and bilateral uveitis. Her family history included mixed connective tissue disease in her eldest daughter. Laboratory findings indicated an elevated erythrocyte sedimentation rate, hypergammaglobulinemia, and elevation of serum lysozyme and angiotensin converting enzyme levels. Antinuclear antibodies, anti-SSA antibodies, anti-SSB antibodies were positive, while tuberculin test was negative. Chest X-rays showed bilateral hilar lymphadenopathy and small nodular shadows in both lung fields. Increases in lymphocytes and the CD4/CD8 ratio of T cells were noted in alveolar lavage fluid. Renal biopsy revealed non-caseous granulomas. Other remarkable findings included positive Schirmer's test, apple tree lesions by sialography and chronic sialoadenitis by biopsy of the labial minor salivary gland. On the basis of all these findings, we diagnosed her as suffering from sarcoidosis with Sjögren's syndrome. After oral administration of prednisolone, her shortness of breath, hilar lymphadenopathy and small nodular shadows in the lung field disappeared, but the patient was transferred to the department of urology due to the onset of hydronephrosis. This case is noteworthy because sarcoidosis associated with Sjögren's syndrome has been reported in only 11 cases in the literature.

CD4-CD8 Ratio↗

PubMed1992

The toxic effects of bis (tributyltin) oxide on the rat thoracic aorta.

The toxic effects of bis (tributyltin) oxide (TBTO) on the ultrastructure and permeability of rat thoracic aorta were studied electron microscopically and the accumulation sites of tin were determined with an X-ray microanalyzer. Male Wistar rats received 0.05ml/kg of TBTO as an emulsion in 1 ml of distilled water through a stomach tube. After time intervals of 2, 4, 6, 8, 10, 12 h after intubation, thoracic aortae were isolated and prepared for electron microscopy. Marked swelling of mitochondria in the aortic endothelial cells appeared at 4 h after TBTO treatment. By x-ray microanalysis, tin L-alpha peaks (3.44 keV) were obtained from these swollen mitochondria. Subendothelial edema progressed between 6 and 8 h after TBTO treatment. By tracer experiment, it was seen that large amounts of peroxidase reaction products filled the expanded subendothelial space. At 12 h after TBTO treatment, degenerative changes of the endothelial cells were prominent. These results indicated that orally administered TBTO accumulated in the mitochondria of the endothelial cells of thoracic aorta. The direct toxic effects of TBTO on mitochondria might induce severe damage to the endothelial cells and cause disturbance of the permeability barrier function of the endothelial layer and subendothelial edema.

Animals↗

PubMed1992

[A case of mediastinal lymphatic cyst possibly originating from the right thoracic duct].

A 33-year-old male was admitted to our hospital because of an abnormal shadow in the right superior mediastinum on chest X-ray, which was first noted about half a year before his admission. Several diagnostic procedures, including fiber bronchoscopy, CT scan and MRI; however, no final diagnosis could be made. Thoracotomy was performed with the presumed diagnosis of benign mediastinal cystic tumor. Entry of the right thoracic duct into the cyst was observed at operation. Histological examination revealed that the cyst was lined by mono-layered cuboidal epithelial cells with lymphocytic infiltration in the wall of the cyst. The mono-layered cuboidal epithelium of the thoracic duct gradually changed to the epithelium of the cyst. Twenty ml of colorless transparent fluid was aspirated from the cyst. Analysis of aspirated fluid revealed low concentration of several substances except LDH compared to the values of the previously reported normal standards and other reported cases. From these findings, the cyst was diagnosed as mediastinal lymphatic cyst. Entry of the thoracic lymphatic duct into the mediastinal lymphatic cyst is a rare occurrence, and it is of interest to speculate on its relationship to the origin of the lymphatic cyst.

Adult↗

PubMed1992

[Mediastinitis with bilateral empyemas following neck phlegmon].

A 46-year-old male complaining of fever and neck swelling was transferred to our department because of bilateral empyemas in the pleural spaces following neck phlegmon. A culture of the right pleural effusion obtained at his local hospital revealed Gram-positive anaerobic cocci. Chest roentgenogram showed bilateral effusions and widening of the upper mediastinum. Neck roentgenogram confirmed widening of the retropharyngeal space. CT clearly demonstrated a continuous lesion from the neck to the mediastinum and occupying the pleural spaces bilaterally. The patient responded to intravenous antibiotics and tube drainage of the pleural cavities, and was discharged after 10 weeks of hospitalization. Because no mediastinal abscess requiring drainage was recognized on CT, surgical drainage of the mediastinal space was not performed. Sequential CT was used to follow the lesion in the retropharyngeal space, mediastinum and pleural spaces, to check and reposition the tubes for drainage of pleural exudate.

Cellulitis↗

PubMed1991

Modification of gelsolin with 4-fluoro-7-nitrobenz-2-oxa-1,3-diazole.

Pig plasma gelsolin was modified with the fluorescent reagent 4-fluoro-7-nitrobenz-2-oxa-1,3-diazole (NBD-F) for lysyl residues. The relationship between the gelsolin activity and the degree of NBD labeling suggested that a single lysyl residue, which reacted five times slower than the other reactive lysyl residues, was essential for the activity. Taking advantage of the slow reactivity of the essential residue, active NBD-gelsolin was prepared. Limited cleavage of NBD-gelsolin by chymotrypsin indicated that the fluorescent reagents were randomly incorporated into all fragments observed. When NBD-gelsolin formed a gelsolin/actin (1:2) complex in the presence of micromolar Ca2+, the fluorescence spectra of NBD-gelsolin were red-shifted by 5 nm and the intensity decreased by 30%. However, on binding to phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2), the fluorescence spectra were blue-shifted by 5 nm with a concomitant increase in intensity by 20%. The addition of PtdIns(4,5)P2 to the NBD-gelsolin actin (1:2) complex restored the fluorescence spectra to that obtained in the presence of PtdIns(4,5)P2 alone. These results indicated that NBD-gelsolin, selectively labeled on lysyl residues not essential for activity, can be a useful probe to monitor the binding of PtdIns(4,5)P2 and actin.

4-Chloro-7-nitrobenzofurazan↗

PubMed1991

Cadmium toxicity in the thyroid gland of pregnant rats.

The toxic effects of cadmium on the thyroid gland of pregnant rats were studied with an electron microscope and an X-ray microanalyzer. Serum levels of thyroid hormones (T3 and T4) were also analyzed. Deterioration of the rough-surfaced endoplasmic reticulum occurred in the thyroid follicular epithelium on the fifth day of cadmium treatment. Large intracellular vacuoles, which arose from dilated cisternae of the rough-surfaced endoplasmic reticulum, were fused together, and marked swelling of the mitochondria was also noted. Thyroglobulin-secreting granules at the apical cytoplasm were decreased in number. By energy dispersive X-ray microanalysis, cadmium peaks were preferentially obtained from swollen mitochondria in the follicular epithelial cells. Serum levels of T3 and T4 were significantly decreased in cadmium-treated rats dams when compared to those of controls. In the present experiment, cycloheximide also caused degenerative changes in the rough-surfaced endoplasmic reticulum and the disappearance of thyroglobulin-secreting granules. Cycloheximide is a known inhibitor of protein synthesis on cytosolic ribosomes. These results indicated that accumulated cadmium in the mitochondria of thyroid follicular epithelial cells might disturb the oxidative phosphorylation of this organelle and the loss of energy supply possibly caused the inhibition of the synthesis and release of thyroid hormones.

Animals↗

PubMed1991

Alloimmune neonatal neutropenia in monozygous twins. High-dose intravenous gammaglobulin therapy.

An indirect immunofluorescence test using a flow cytometer (FACS420) was useful for detection of antineutrophil antibodies (anti-NA2 antibodies) in a case of monozygous twins with alloimmune neonatal neutropenia. When high-dose intravenous gammaglobulin (300 mg/kg for five consecutive days) was given to one twin, the increase in neutrophils was not obvious. Although neutropenia persisted for about three months, no infections were observed in either of the twins.

Autoimmune Diseases↗