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Biomedical subjects

Y Harada

Publications and source records attributed to Y Harada.

At least 577 records · Page 32Linked to original sources
PubMed1989

[Ontogeny of pancreatic gastrin cells in neonatal rat].

It is well known that gastrin immunoreactive cells are observed in the fetal and postnatal rat pancreas. The role of the gastrin cells is unknown, however, it has been suspected that pancreatic gastrin may influence the development of pancreas and the gastrointestinal tract. The present study shows the localization of pancreatic gastrin cells and the ability of auto-proliferation of them in development. Gastrin cells were seen in 0-d to 2-wk-old rats in islet and in 0-d to 4-wk-old rats among exocrine cells. The ratio of gastrin cells to islet cells decreased in neonatal development and in rats older than 14-d gastrin cells were never observed in islet. Labeling indices of pancreatic gastrin cells after one injection of tritiated thymidine were 2.6% to 4.6% for 10 days after birth. It was suggested that gastrin cells have the ability of autoproliferation for 10 days after birth.

Age Factors↗
PubMed1989

[Pulmonary valve replacement using the right ventricle-pulmonary artery bypass without cardiopulmonary bypass].

We underwent pulmonary valve replacement using the right ventricule pulmonary artery bypass without cardiopulmonary bypass. This right heart bypass was consisted of the vascular graft and the polystyrene tube. The vascular graft was anastomosed to the main pulmonary artery and the polystyrene tube was inserted into the free wall of the right ventricle. These were connected with a cannulating magnetic flow probe. After the bypass was established, the pulmonary artery was clamped and divided. The pulmonary valves were excised and the pulmonary valve replacement was undergone with a pulmonary valve homograft. Hemodynamics during the pulmonary valve replacement was stable and the postoperative course was uneventful. One month later, the cardiac catheterization and cineangiography showed that the implanted homograft was effective sufficiently. We concluded that this right heart bypass was useful for the pulmonary valve replacement.

Anastomosis, Surgical↗
PubMed1989

[Atypical computed tomographic features of meningioma: a case report].

Diagnosis of intracranial meningiomas with computed tomography (CT) is usually easy. However, some authors have reported cases preoperatively misdiagnosed because of atypical computed tomographic features. We report a case of non-cystic meningioma presenting a ring enhanced mass lesion, with CT scan. A 48-year-old male was admitted to our hospital on January 5, 1987, because of progressive monoparesis of his left lower limb. This had continued for 1 1/2 years. Neurological examination revealed monoparesis, hypesthesia and decreased deep sensation of the left lower limb. X-ray films of the skull appeared normal. A CT scan demonstrated a ring-like high density mass attached to the falx in the right frontoparietal area with perifocal low density. The ring-like high density was irregularly increased with contrast enhancement. Right carotid angiograms showed a doughnut like tumor stain without meningeal blood supply. Brain scintigrams revealed a dense round hot lesion in the frontoparietal area at 5 minutes, and the hot lesion was still visualized after 90 minutes. We diagnosed a cystic parasagittal meningioma. A right frontoparietal craniotomy was performed, and total removal of the parasagittal tumor was made. The center of the tumor was very soft but it could not be said that it was not cystic. Histologically the tumor was a meningotheliomatous meningioma. The center of the tumor, which was very soft, was necrotic with arteriolar hyalinization. The meningioma cells survived around the patent vessels. These intact meningioma cells were scattered like islands in extensive necrosis. This is so called "oasis phenomenon" indicating that the necrosis of the tumor was caused by intratumoral ischemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Carotid Arteries↗
PubMed1989

Lower levels of vitamin C in plasma and urine of Japanese male smokers.

We studied the vitamin C status of smokers and nonsmokers among staff members of our university in 1982. This paper describes the results from the 1983-85 studies. Plasma vitamin C levels (M +/- SD, mg/dl) from smokers and nonsmokers, respectively, were as follows: 0.49 +/- 0.15 (n = 51) and 0.72 +/- 0.23 (n = 73) in 1983, 0.56 +/- 0.13 (n = 48) and 0.84 +/- 0.21 (n = 88) in 1984, and 0.52 +/- 0.15 (n = 56) and 0.86 +/- 0.24 (n = 93) in 1985. The differences between smokers and nonsmokers are all highly significant. Urinary vitamin C levels (M +/- SD, mg/dl) from smokers and nonsmokers, respectively, were 1.8 +/- 0.6 and 2.6 +/- 0.9 in 1983 and 2.0 +/- 0.7 and 2.9 +/- 1.0 in 1984. These differences between the two groups are also highly significant. Both groups were similar in age, height, weight, general health parameters, and vegetable and fruit consumption. Plasma and urinary vitamin C levels were significantly higher in smokers taking vitamin C supplement than in those not taking vitamin C supplement.

Adult↗
PubMed1989

[A new valved conduit with commissures using a glutaraldehyde preserved equi pericardium].

We developed a new valved conduit with commissures using a glutaraldehyde preserved equine pericardium, and implanted this prosthesis between the right ventricle and the pulmonary artery in the dog to examined the movement of the valve. Our new prosthesis consists of a conduit and three leaflets. Each leaflet is sutured to the inner surface of the conduit to form a valve. The adjacent free edges of the leaflets are sutured together by placing a mattress stitch 2 mm from their attachment to the conduit so that the leaflets form commissures. These commissures are designed to facilitate prompt coaptation of the three leaflets in diastole. A radiopaque marker is anchored to the center of the free edge of each leaflet and to the outer surface of the conduit to investigate its movement. The movement of the radiopaque markers studied by cineangiography revealed good coaptation of three leaflets in diastole and their full opening in systole. These findings demonstrated that the valve in our prosthesis might function well to prevent regurgitation across it.

Animals↗
PubMed1989

[Long-term follow-up study of transcatheter arterial chemotherapy in patients with advanced breast cancer].

Intra-arterial infusion chemotherapy (I.A) was applied to 32 cases with advanced breast cancer. The subclavian artery was intubated and one shot of 30 mg of adriamycin was given every 3 days, with a total dose of over 150 mg. Then mastectomy was performed after this chemotherapy. Long-term follow-up study revealed that the response rates of the primary tumor to I.A chemotherapy provided the prospects for their prognosis. The 3-and 5-year survival of good responders (% tumor regression greater than or equal to 70%) was significantly better than those of poor responders (% tumor regression less than 70%). Then, four patients with advanced breast cancer were treated with combination of I.A infusion chemotherapy of Adriamycin and photoradiation by argon laser. The mean interval time for 50% tumor regression was shorter than in the cases treated with Adriamycin alone. In vitro, the effects of the photoradiation for MCF-7 breast cancer cell line were observed only at a high concentration of Adriamycin.

Breast Neoplasms↗
PubMed1989

[A scanning electron microscopic study on the arteriovenous anastomoses of rabbit ear using corrosive resin casts].

Arteriovenous anastomoses (AVAs) partake in the regulation of blood flow, and although it has been speculated that AVAs in the rabbit ear play a major role in the regulation of the body temperature, no documented work is available on the structural characteristics of AVAs in the rabbit ear. Accordingly, the purpose of this investigation was to determine the frequency of AVAs and their structural characteristics by using the vascular corrosive resin casts and further examination under a scanning electron microscope (SEM). This method permitted not only the visualization of a three-dimensional view of AVAs, but also depicted a clear differentiation between AVAs and arterioles or venules. Within the vascular architecture of rabbit ear, three distinctive vascular layers could be identified. The frontal and dorsal epithelial vascular layers are distributed underneath the epithelium and formed with nearly all capillaries, and the intermediate vascular layer which is established with main arteries, veins and their branches. The AVAs were observed in all three vascular layers, although various venous valves were concentrated primarily in the intermediate vascular layer. In tabulating the frequency of appearance of AVAs, the mean number was 81.5 per centimeter square. The mean number of AVAs in each of the three vascular layers was 31.1 in the frontal layer, 17.1 in the intermediate layer and 33.1 in dorsal layer, respectively. The vasculature of rabbit ear was further anatomically divided into tip, middle and root portions. The mean number of AVAs in each portion, from the tip to the root was 112.9, 49.4 and 84.4, respectively. Several essential types of AVAs were observed, such as the S-shaped and similar forms which were the predominate type. Others observed were U-shaped, straight, Y-shaped and tri-branching types. Most AVAs within the intermediate vascular layer, consisting of a few small vessels which were mainly capillaries and venules, connected to the anastomosing portion of AVA. The high occurrence and strategic location of AVAs in the rabbit ear strongly suggest that AVAs in the rabbit ear partake in thermal regulation.

Animals↗
PubMed1989

[The results of surgical treatment of total anomalous pulmonary venous return in neonates].

By the time, the results of surgical treatment for total anomalous pulmonary venous return have been unsatisfactory. From 1981, we changed a surgical procedure fro Gersony-Malm procedure to the posterior approach method, and a surgical technique from the deep hypothermia and the circulatory arrest to the moderate hypothermia and the pump perfusion. Consequently, the results of surgical treatment was improved. From 1981 to 1987, 18 neonates with total anomalous pulmonary venous return underwent corrective operations in our institute. This diagnosis was decided by echocardiography without cardiac catheterization, because the preoperative status of these neonates were poor. Under the cardiopulmonary bypass, we performed the posterior approach method for type I and III, the cut-back method and Van Praagh procedure for II and IV without aortic clamping. According to the posterior approach method, the atrial septal defect was closed through the left atrial incision and the left atrium was anastomosed to the common pulmonary trunk during ventricular fibrillation. The incision was limited within the common pulmonary trunk or the vertical vein and was not extended into the pulmonary veins. According to cut-back method and Van Praagh procedure, the coronary sinus was closed internally so as to avoid the postoperative conduction disturbance. There were four hospital deaths (22.2%). The causes of deaths were pulmonary hypertension in two, low cardiac output in one, and intracranial bleeding in one. From the results of our institution, we concluded that the primary factors determining the outcome were the condition of the patients prior to repair and the severity of pulmonary hypertension.

Cardiopulmonary Bypass↗
PubMed1989

[Clinico-immunological studies of pulmonary tuberculosis in the elderly].

We studied tuberculin reactivity and clinical course after starting chemotherapy in patients with active pulmonary tuberculosis divided by four age-groups less than 29, 30-49, 50-69 and 70 years and more. The skin test to tuberculin purified protein derivative (PPD) was examined in 178 cases of active pulmonary tuberculosis, 120 cases of lung cancer, 25 cases of atypical mycobacteriosis and 466 cases of the other respiratory diseases. The average size of tuberculin reaction in pulmonary tuberculosis decreased with age, but significantly higher than that in patients with other nontuberculous pulmonary diseases of the same age-group. The size of PPD skin test in the group of 70 years and more was significantly lower than other age-groups in pulmonary tuberculosis. We compared the time required for negative conversion of sputum by culture after primary chemotherapy among the different age-groups in pulmonary tuberculosis. It revealed that the time for negative conversion tended to be longer with age, and the time in the group 70 years and more was significantly longer than that of the group less than 29 years of age, although no significant differences in the radiographic severity and conditions of chemotherapy were observed. Finally, the PPD-induced lymphocyte proliferation test in vitro was done in newly diagnosed patients with pulmonary tuberculosis. The patients were divided into two groups by the size of PPD skin test (high responder more than 16 mm and low responder less than 15 mm of erythema induced by PPD).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

Observation of the glycocalyx of the organ of Corti: an investigation by electron microscopy in the normal and gentamicin-treated guinea pig.

The ultrastructure of the glycocalyx of the organ of Corti in the normal and gentamicin-treated guinea pig was investigated at the electron microscopic level by using the ruthenium red staining technique. The glycocalyx was evident over the whole apical surface of both sensory and supporting cells. The entire length of the stereocilia of both inner and outer hair cells was seen to be covered by a glycocalyx, which interconnected the neighbouring stereocilia. In the gentamicin-treated animals, the fusion process between the stereocilia was revealed and a decrease of the glycocalyx was noticed at the point where fusion started. These findings suggest that the glycocalyx may play an important role in holding the stereocilia together in a bundle, yet prevent their close contact by means of its strong negative charge.

Animals↗
PubMed1989

[Multiple organ failure following open heart surgery in adults].

The cases multiple organ failure (MOF) which occurred post-operatively following open heart surgery in adults were studied on a pre and post-operative hemodynamics. Post-operative low cardiac output syndrome (LOS) was thought to result in decreased renal and hepatic perfusion with subsequent ischemic damage to these organs. Therefore, to management MOF, we have to prevent post-operative LOS, for example, administration of cathecholamine and vasodilator, and early clinical application of IABP and ventricular assist device (VAD). In a post-operative hemodynamics, the cases of severe right ventricular failure tend to have more protracted MOF. It was though that MOF could be minimized with shortened cardiopulmonary bypass duration, and early application of assisted circulation.

Adult↗
PubMed1988

Characterization of calcium channel antagonist binding sites labeled by [3H]nitrendipine in porcine coronary artery and aorta.

The receptor sites for dihydropyridine calcium channel antagonists in porcine coronary artery were characterized with [3H]nitrendipine (NTD), and were compared with those in the thoracic aorta. Specific [3H]NTD binding in the coronary artery and aorta was saturable, reversible and of high affinity. These sites showed a pharmacological specificity and stereoselectivity characteristic of the receptor sites for dihydropyridine calcium channel antagonists. The pharmacological potencies of nitrendipine, nifedipine, nisoldipine, (+)-PN 200-110 and (-)-PN 200-110 in the isolated porcine coronary artery correlated well with their potencies in competing for [3H]NTD binding sites. The Hill coefficients for the competition curves for these antagonists in the porcine coronary artery and aorta were close to one. Verapamil partially inhibited specific [3H]NTD binding in both tissues. The [3H]NTD binding was increased by Mg2+ and Ca2+ but was markedly reduced by EDTA. Thus, the present study has shown that [3H]NTD selectively labels the pharmacologically relevant dihydropyridine receptors in the porcine coronary artery and that there is no significant difference between the binding characteristics of the receptor sites in the coronary artery and aorta of pigs.

Animals↗
PubMed1988

Muscarinic receptor subtype in porcine coronary artery.

The specific binding of (-)-[3H]QNB (quinuclidinyl benzilate) in membrane fractions of porcine coronary artery was saturable, of high affinity and stereoselective. It has been shown that there exist (-)-[3H]QNB binding sites with high (Ki = 12 nM)- and low(Ki = 1010 nM)-affinity for pirenzepine in the coronary artery but predominantly low-affinity sites in cardiac muscle. AF-DX 116 and gallamine showed a lower affinity to (-)-[3H]QNB binding sites in the coronary artery compared to cardiac muscle. Thus, the present study suggests that porcine coronary artery contains a significant number of muscarinic receptors, probably both M1 and M2 subtypes.

Animals↗
PubMed1988

Direct observation of molecular motility by light microscopy.

We used video-fluorescence microscopy to directly observe the sliding movement of single fluorescently labeled actin filaments along myosin fixed on a glass surface. Single actin filaments labeled with phalloidin-tetramethyl-rhodamine, which stabilizes the filament structure of actin, could be seen very clearly and continuously for at least 60 min in 02-free solution, and the sensitivity was high enough to see very short actin filaments less than 40 nm long that contained less than eight dye molecules. The actin filaments were observed to move along double-headed and, similarly, single-headed myosin filaments on which the density of the heads varied widely in the presence of ATP, showing that the cooperative interaction between the two heads of the myosin molecule is not essential to produce the sliding movement. The velocity of actin filament independent of filament length (greater than 1 micron) was almost unchanged until the density of myosin heads along the thick filament was decreased from six heads/14.3 nm to 1 head/34 nm. This result suggests that five to ten heads are sufficient to support the maximum sliding velocity of actin filaments (5 micron/s) under unloaded conditions. In order for five to ten myosin heads to achieve the observed maximum velocity, the sliding distance of actin filaments during one ATP cycle must be more than 60 nm.

Actins↗