Biomedical subjects

Y Toyama

Publications and source records attributed to Y Toyama.

188 records · Page 11Linked to original sources

PubMedDate not supplied

Ultrastructural features and pathogenesis of decapitated spermatozoa in a boar.

A boar with decapitated spermatozoa was examined. The growth rate and libido were normal. The right testis was in the scrotum, but the left one was intra-abdominal. Ejaculated spermatozoa and tissue specimen from both testes were observed by light and electron microscopy. Only tailless heads and headless tails of spermatozoa were observed in the ejaculate. The ratio of heads to tails was about 1:4. Motility of the headless tails was about 25%. The proximal extremity in the tail was occupied by the proximal centriole. The basal plate could not be found in the head or in the tail. Pathogenesis of decapitated spermatozoa in the present case was analysed by investigating spermiogenesis in the scrotal testis. Since the pair of centrioles failed to approach the nucleus, mechanical connection between the proximal centriole and the nucleus did not seem to be established. In addition, the basal plate was not formed on the nuclear membrane. Since the ratio of tailless heads to headless tails was also 1:4 in the testis, it was concluded that the heads had already detached the tails in the testis.

Animals↗

PubMedDate not supplied

Effect of concentration on enhanced sedimentation rate of erythrocytes in an inclined vessel.

The enhanced rate of sedimentation of erythrocytes in an inclined rectangular vessel was measured under microscopic and macroscopic conditions. The velocity profile, V(x), and the thickness, delta, of the upflow layer generated below the downward-facing wall in the sedimentation vessel were measured under a microscope with polystyrene latex as a tracer particle. Here, x is the distance from the vessel wall. All the data of the velocity profile are represented by a single curve, [Vmax- V(x)]/Vmax = [(delta -x)/delta]2, irrespective of the volume fraction, H, and tilt angle, theta, in the range of 0.05 < H < 0.30 and 10 degrees < theta < 40 degrees, where Vmax is the maximum velocity found at the upflow boundary. The rate of fall of the top surface of the suspension v(H, theta) fits the function, v(H, theta) = v(0, theta)(1-H)exp[-(aH + bH2)], well, irrespective of H and theta. These experimental results are compared with the theory of Acrivos and Herbolzheimer.

Blood Sedimentation↗

PubMedDate not supplied

Pharmacologically stimulated portal flow measurement by magnetic resonance imaging for assessment of liver function.

PURPOSE: To evaluate pharmacologically stimulated portal flow measured by magnetic resonance (MR) imaging for assessment of liver function. MATERIALS AND METHODS: Pharmacologically stimulated portal flow was measured by phase contrast MR imaging in 27 patients when they were undergoing abdominal angiography for liver tumors or gall bladder cancer. The patients included 11 cases of liver cirrhosis and eight of chronic hepatitis. Pharmacological stimulation was done by infusion of 10 microg/Kg of nicardipine hydrochloride into the superior mesenteric artery through an angiographic catheter. We examined the correlation between stimulated or non-stimulated portal flow and biochemical liver function tests. RESULTS: Correlation coefficients and their corresponding p values between non-stimulated portal flow and the indocyanine green residual rate at 15 min after injection (ICG R15), serum albumin (ALB), total bilirubin (TB), cholinesterase (CHE), and hepaplastin test (HP) were--0.414 (0.056), 0.296 (0.134), -0.570 (0.002), 0.289 (0.153), and 0.321 (0.126), respectively, whereas those between stimulated portal flow and ICG R15, ALB, TB, CHE, and HP were--0.561 (0.007), 0.411 (0.033), -0.509 (0.007), 0.445 (0.023), and 0.494 (0.014), respectively. CONCLUSION: Stimulated portal flow showed better correlations with biochemical liver function tests than non-stimulated portal flow. It is suggested that stimulated portal flow measurement is more useful for the evaluation of liver function than non-stimulated portal flow measurement.

Aged↗

PubMedDate not supplied

Prognostic relevance of urokinase type plasminogen activator, its receptor and inhibitors in chondrosarcoma.

The plasminogen activation system plays an important role in enhancing pericellular proteolysis of tumor invasion/metastasis and in autocrine/paracrine tumor growth stimulation. To investigate the prognostic significance of the plasminogen activation system in human chondrosarcoma, the immunohistochemical expression of urokinase-type plasminogen activator (uPA), urokinase-type plasminogen activator receptor (uPAR), plasminogen activator inhibitor, 1 (PAI-1) and 2 (PAI-2) were analyzed in 28 patients with chondrosarcoma. In multivariate survival analysis, histological grade (p = 0.0008) and location (p = 0.02) were independent risk factors for local relapse. For metastasis-free survival, uPA index (p = 0.006) and PAI-2 index (p = 0.04) were independent prognostic factors. PAI-2 index (p = 0.02), uPAR index (p = 0.02) and histological grade (p = 0.03) predicted total survival. These results demonstrated the usefulness of uPA, uPAR and PAI-2 expression as biological prognostic indicator and the importance of the plasminogen activation system in tumor progression and metastasis in chondrosarcoma.

Adolescent↗

PubMedDate not supplied

Neonatally administered diethylstilbestrol retards the development of the blood-testis barrier in the rat.

Newborn rats were treated with 10 microg of diethylstilbestrol (DES) on alternate days from the 2nd to the 12th postnatal day, and the testes were sequentially examined up to 105 days of age by light, electron, and confocal laser microscopy. In control rats, spermatozoa and step 19 spermatids were observed in stage VIII seminiferous tubules at 56 days of age. Spermatogenic cells in DES-treated rats differentiated normally from birth until 21 days of age, after which differentiation continued only to the pachytene-spermatocyte stage. From this age onward, spermatogenic cells older than pachytene spermatocytes were not found until 56 days of age. After this point, the cells resumed differentiation and finally became spermatozoa by 91 days of age; that is, 35 days later than control rats. Electron and confocal laser microscopy showed that in the normal rat, the formation of the ectoplasmic specialization between adjoining Sertoli cells was observed as early as 20 days of age. In contrast, the specialization was not formed until 56 days of age in DES-treated rats. Furthermore, the delay in functional maturation of this structure as the blood-testis barrier was confirmed by intercellular tracer experiments. It is clear that neonatal administration of DES delayed the establishment of the blood-testis barrier for 4 weeks. Consequently, during this period, pachytene spermatocytes were exfoliated from the seminiferous epithelium without completion of meiosis.

Aging↗

PubMedDate not supplied

Blood transfusions impair anastomotic wound healing, reduce luminol-dependent chemiluminescence, and increase interleukin-8.

BACKGROUND/AIMS: Several studies have shown that perioperative blood transfusion increases the risk of infectious complications after surgery or trauma, however, the mechanisms behind the susceptibility to infection and impaired wound healing are not clear. This study was designed to investigate the effects of blood transfusion on anastomotic wound healing, luminol-dependent chemiluminescence, and interleukin-8. METHODOLOGY: Male Wistar rats were divided into seven groups: groups C and Tx underwent laparotomy and the other groups underwent gastrectomy and gastroduodenostomy. Groups C and G received saline; groups Tx and GT received whole blood; and groups GPT, GAT, and GRT received plasma, autologous blood, and irradiated, leukocyte-depleted whole blood, respectively. The breaking strength of the anastomosis, and plasma factor XIII, interleukin-8, and luminol-dependent chemiluminescence levels were measured. RESULTS: The plasma XIII level in group GT was significantly (P < 0.05) lower that in groups G, GPT, GAT, and GRT. The maximum breaking strength was significantly reduced in groups GT, GRT, GPT, and GAT compared to the other groups, and there was no significance between different types of transfusion. Luminol-dependent chemiluminescence levels in groups GT were severely reduced, while the and luminol-dependent chemiluminescence levels in groups GRT, GPT, and GAT were almost the same as the levels in group G. The plasma interleukin-8 levels were higher in the transfused groups, and lower in groups GRT, GPT, and GAT. CONCLUSIONS: Blood transfusions increased the incidence of anastomotic abscess and impaired anastomotic wound healing. These might be related to the reduced luminol-dependent chemiluminescence and increased interleukin-8. Autologous blood, plasma, and irradiated, leukocyte-depleted packed cells can abrogate these effects.

Anastomosis, Surgical↗

PubMedDate not supplied

[Effects of hot water bath or sauna on patients with congestive heart failure: acute hemodynamic improvement by thermal vasodilation].

The acute hemodynamic effects of thermal vasodilation caused by exposure to hot water bath or sauna in chronic congestive heart failure were investigated in 32 patients (mean age 57 +/- 15 years old) with dilated cardiomyopathy (25 idiopathic and 7 ischemic). The clinical symptoms were New York Heart Association Class II in 2 patients, III in 17 and IV in 13, and the mean ejection fraction was 25 +/- 9% (9-44%). Exposure to hot water bath was for 10 minutes at 41 degrees C in a semi-sitting position, and to sauna for 15 minutes at 60 degrees C in a supine position using a special far infrared ray sauna chamber. Blood pressure, electrocardiogram, two-dimensional and Doppler echocardiograms, expiration gas, and intracardiac pressure tracings were recorded before (control), during, and 30 minutes after hot water bath or sauna. 1. The increase in oxygen consumption was only 0.3 Mets during hot water bath or sauna, and returned to the control level 30 minutes later. 2. The deep temperature in the main pulmonary artery increased by 1.0-1.2 degrees C on average at the end of hot water bath or sauna. 3. Heart rate increased significantly (p < 0.01) by 20-25/min during bathing and still increased 30 min later. 4. Systolic blood pressure did not change significantly during and after hot water bath or sauna, while, diastolic blood pressure decreased significantly during (p < 0.05) and after sauna (p < 0.01), and after hot water bath (p < 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMedDate not supplied

CT angiography with helical CT in the assessment of acute stage of subarachnoid hemorrhage.

PURPOSE: We evaluated the usefulness of helical CT in the preoperative assessment of ruptured cerebral aneurysms during the acute stage of subarachnoid hemorrhage (SAH). METHODS: Nine patients with 13 aneurysms were included in this study. Helical CT scanning was performed before preoperative angiography. The section thickness and the table-movement speed were 1-2 mm/sec. Helical CT scanning was started 20 sec after the start of injection of 100 ml of contrast agent at a rate of 3 ml/sec. RESULTS: The average CT value of SAH was 51.9 Hounsfield units (HU) and that of the aneurysm was 191.7 HU. Nine of 13 aneurysms greater than 3.0 mm in diameter were identified by three-dimensional CT angiography (3DCTA). In seven cases, the information provided by 3DCTA images, maximum intensity projection images, and multiplanar images, was very useful in surgical planning, providing information concerning the configuration of the neck and relationships between the aneurysm and brain parenchyma. Four aneurysms in two cases were not depicted by 3DCTA because they were located outside the imaging volume. This problem was overcome by changing the imaging volume according to the extent of origin of SAH. CONCLUSION: We conclude that helical CT in patients with SAH is useful for surgical planning, providing valuable information that cannot be obtained by conventional angiography.

Acute Disease↗