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Biomedical subjects

Y Okuda

Publications and source records attributed to Y Okuda.

At least 271 records · Page 15Linked to original sources
PubMed1993

Forebrain ischemia in the gerbil increases lambda opiate binding in hippocampal mossy fibers.

Transient forebrain ischemia was produced in gerbils by short-term occlusion of the common carotid arteries under halothane anesthesia. Histological analysis of brains 7 days post-ischemia demonstrated characteristic destruction of CA1 pyramidal cells. lambda Opiate binding (measured with [3H]naloxone in the presence of 300 nM diprenorphine) at 7 days post-ischemia was significantly increased in the stratum lucidum of the hippocampus (the mossy fiber layer), but not in any other region measured, including other hippocampal regions, cortex, amygdala, caudate putamen, thalamus, and hypothalamus. The increase in mossy fiber lambda binding was slow to develop (no increase detected up to 48 h post-ischemia), and long-lasting (binding remained elevated at 32 days post-ischemia). While MK-801 significantly inhibited CA1 pyramidal cell destruction when administered 20 min prior to ischemia, the increase in mossy fiber lambda binding was still evident. None of seven different opioid agonists and antagonists examined had an effect on either the pyramidal cell damage or increased mossy fiber lambda binding seen 7 days after ischemia.

Afferent Pathways↗
PubMed1993

[Experimental study with radiofrequency-induced thermal arterial occlusion].

A preliminary experiment on arterial occlusion using radiofrequency energy was performed. A surgitron FFPF was used as a radiofrequency power generator, and a Tracker 18 catheter was used as a probe insulator. A 10 mm length of the guide wire protruding from the tip of catheter was used as the radiofrequency probe. To examine the safety of this procedure within the vessels, the following experiments were performed. A 2.5 mm diameter dimple at the surface of a sausage was filled with human blood. We inserted various lengths of non-insulated guide wire into the dimple and supplied radiofrequency power. We then measured the time until air bubbles appeared in the dimple. With a 10 mm length of non-insulated guide wire, this took over 30 sec. Animal experiments were carried out in 17 canine arteries. The diameter of these arteries ranged from 1.3 to 3.7 mm. Before the procedure, angiograms were taken using a 5 F catheter from the right femoral artery. A tracker 18 catheter and guide wire were inserted to the target position co-axially. The guide wire was attached to the radiofrequency generator. The tip of the guide wire functioned as the convergence point of an electrically conducting induced current. Treatment was performed by supplying radiofrequency power of various durations.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

[A study of transsplenic CO2 gas enhanced portal angioechography].

Transsplenic CO2 gas enhanced portal angioechography was examined. The spleen of three dogs was punctured by 23 gauge needle with two side holes. From 5 ml to 20 ml of CO2 gas was injected into the splenic vein via the splenic parenchyma, and elevation of echo level of the liver was observed. Hematoma was not seen at the site of puncture. Good image was obtained in the case of 5 ml CO2 injection. In one dog with pseudotumor in the liver, the hyperechoic tumor changed into negative enhanced nodule after CO2 gas enhancement. Transsplenic CO2 gas enhanced portal angioechography is thought to be useful to evaluate hepatic tumors.

Animals↗
PubMed1993

[MR tractography--visualization of structure of nerve fiber system from diffusion weighted images with maximum intensity projection method].

We developed a new noninvasive technique to visualize the anatomical structure of the nerve fiber system in vivo, and named this technique magnetic resonance (MR) tractography and the acquired image an MR tractogram. MR tractography has two steps. One is to obtain diffusion-weighted images sensitized along axes appropriate for depicting the intended nerve fibers with anisotropic water diffusion MR imaging. The other is to extract the anatomical structure of the nerve fiber system from a series of diffusion-weighted images by the maximum intensity projection method. To examine the clinical usefulness of the proposed technique, many contiguous, thin (3 mm) coronal two-dimensional sections of the brain were acquired sequentially in normal volunteers and selected patients with paralyses, on a 1.5 Tesla MR system (Signa, GE) with an ECG-gated Stejskal-Tanner pulse sequence. The structure of the nerve fiber system of normal volunteers was almost the same as the anatomy. The tractograms of patients with paralyses clearly showed the degeneration of nerve fibers and were correlated with clinical symptoms. MR tractography showed great promise for the study of neuroanatomy and neuroradiology.

Aged↗
PubMed1993

Intra-operative blood pressure control by prostaglandin E1 in patients with hypertension and ischemic heart disease--a multi-center study.

The purpose of this multi-center study was to evaluate the efficacy and safety of prostaglandin E1 (PGE1) administration in achieving deliberate hypotension and in treating intraoperative hypertension for patients with a history of hypertension and ischemic heart disease. PGE1 (0.08 microg.kg(-1).min(-1)) decreased systolic blood pressure from 125 +/- 29 to 106 +/- 22 mmHg (mean +/- SD) in the deliberate hypotension group (n = 158) and from 155 +/- 34 to 125 +/- 32 mmHg in the antihypertension group (n = 55). The heart rate significantly increased from 80 +/- 15 to 85 +/- 18 beats.min(-1) in the deliberate hypotension group, but was not significantly altered in the antihypertension group. The time required to obtain the desired level of blood pressure was approximately 20 min in the deliberate hypotension group. When the infusion was stopped, blood pressure returned approximately to the preinfusion level within about 20 min. No rebound hypertension was observed. PGE1 significantly increased the urine flow in patients who had a low urine flow before PGE1 infusion. Thirteen out of 213 patients (5.6%) had side effects such as excessive hypotension (1%), phlebitis (3%), and unexpected tachycardia (1%), which were alleviated gradually after discontinuation of PGE1 infusion. No dysarrhythmia and further ST segment changes in the electrocardiograms were observed. These findings suggest that PGE1 can be safely used to control arterial blood pressure during surgery in patients having preoperative hypertension and ischemic heart disease.

Journal Article↗
PubMed1993

Changes in carpal tunnel shape during wrist joint motion. MRI evaluation of normal volunteers.

This study evaluated dynamically the morphology of the carpal tunnel during the wrist motion. The object was to determine the transverse dimension (TD), anteroposterior (AP) dimension and cross-sectional area (CA) of the carpal tunnel in the neutral, flexed and extended positions. The wrists of eight male and eight female volunteers aged 20 to 38 years were studied. With wrist extension, AP and CA decreased while the TD increased at the pisiform level, and CA increased at the hamate level. With flexion, TD and CA decreased at the pisiform level and CA decreased at the hamate level. The results showed that the median nerve may be subjected to significant pressure at the pisiform level when the wrist is extended. During wrist flexion, the cross-sectional area decreased at both the level of the pisiform and the hook of the hamate.

Adult↗
PubMed1993

Clinical evaluation of a low junction of the cystic duct.

The point of the junction of the cystic duct with the common hepatic duct was studied by means of various preoperative and intraoperative cholangiographic procedures and by gross intraoperative examinations in 468 surgical patients with biliary diseases. The cystic duct entered the hepatic duct at a very low position and was consequently long in 39 patients. The clinical significance of this abnormally low junction of the cystic duct was studied in comparison with 358 patients with gallstones with a normal cystic duct-hepatic duct junction. In the low-junction group with a short common bile duct several complications, including gallstone pancreatitis (7 patients), the Mirizzi syndrome (7), confluence stones (2), gallbladder cancer (3), and congenital dilation of the cystic duct (1), were demonstrated preoperatively. The anomalous junction of the cystic duct with the common bile duct may cause stagnation of bile and/or reflux of pancreatic juice into the bile duct, producing a choledochopancreatic ductal junction and posing difficulties at surgery.

Adult↗
PubMed1993

Hemodynamic effects of lipo-PGE1 on peripheral artery in patients with diabetic neuropathy: evaluated by two-dimensional color Doppler echography.

Twenty non-insulin-dependent diabetic patients were studied to evaluate the hemodynamic effects of lipo-PGE1 (prostaglandin E1 incorporated in lipid microspheres). Improvement of diabetic neuropathy was assessed on the basis of subjective symptoms such as pain, coldness, numbness and dysethesia (subjective) after intravenous administration of lipo-PGE1. After lipo-PGE1 treatment, the subjective symptoms were markedly improved. Hemodynamic effects of this drug on the dorsalis pedis artery were examined using new real-time two-dimensional color Doppler echography. After administration of lipo-PGE1, the cross-sectional area of the dorsalis pedis artery significantly increased from 2.6 +/- 0.2 mm2 to 3.5 +/- 0.2 mm2 (P < 0.01). Moreover, the blood flow index significantly increased from 40 +/- 7 to 61 +/- 11 (P < 0.05). The results of this study suggest that lipo-PGE1 may serve as a useful drug in improving diabetic neuropathy.

Adult↗
PubMed1993

[Examination of the protein binding of lidocaine by gel filtration method].

The protein binding of lidocaine has been studied using gel filtration method. Thermodynamic calculation has been done on results of the experiment. We have found that the primary bond type of lidocaine with serum albumin is hydrophobic interaction, because entropy (delta S) is constantly positive (> 0) under these experimental conditions. The change of the binding ratio between lidocaine and serum albumin with changing pH results from the conformational change of the serum albumin, but the protein binding of lidocaine is also an exothermic reaction. The following conclusions have been obtained. (1) The binding of serum albumin with lidocaine is nonspecific and mainly the result of hydrophobic interaction. (2) At temperature 35 degrees C and pH 7.5, binding constant (K) and binding site (np) of bovine serum albumin with lidocaine are K = 5.9 x 10(3) M-1 and np = 103.5 x 10(-6) M, respectively. (3) Increasing binding ratio with increase in pH is the result of the increase in binding site. This involves the conformational change of albumin, especially that of N-B transition. (4) The binding of serum albumin with lidocaine is an exothermic reaction. Therefore, the binding of lidocaine with serum albumin increases as the temperature decreases.

Chromatography, Gel↗
PubMed1993

[Two cases of acute progressive interstitial pneumonia associated with dermatomyositis--clinical features and immunological disorders].

Some patients of dermatomyositis (DM) with interstitial pneumonia (IP) have common clinical features. Clinical features of these patients are acute onset, very poor prognosis and that patients have fever, arthritis, typical skin rash, mild myositis and show low ratio of CPK/LDH, low incidence of antinuclear antibody (ANA) appearance, low inflammatory signs. We experienced two cases of this category of DM with IP and examined immunological aspects. Case 1. A 52-year-old woman was admitted in June 1, 1990 with a one-month history of arthralgia and a ten-days history of fever, skin rash, myalgia and dyspnea on exertion. On examination she had Gottron's papules on her fingers, erythema on back, bilateral elbows and legs, proximal muscle weakness and arthritis. Fine crackles were audible in the lower lung fields. Laboratory data included CPK 200 IU/l, ALD 3.2 IU/l, LDH 805 IU/l. Analysis of bronchoalveolar lavage fluid (BALF) revealed increased cellularity with lymphocytosis. She was treated with oral corticosteroid (CS), pulse CS, cyclosporin A. Inspite of these therapies, she died of progressive respiratory insufficiency in July 10, 1990. Case 2. A 23-year-old woman was admitted in April 1, 1991, with a two-month history of arthralgia and a one-month history of fever, skin rash, stomatitis, alopecia. On examination she had Gottron's papules on her fingers, erythema on malar, bilateral elbows and legs, arthritis and stomatitis. Laboratory data included CPK 97 IU/l, ALD 8.5 IU/l, LDH 779 IU/l. She began experiencing dry cough and dyspnea on exertion in May 1991. Analysis of BALF revealed increased cellularity with lymphocytosis. She was treated with oral corticosteroid(CS), pulse CS, pulse cyclophosphamide.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1993

[Bronchoalveolar lavage fluid analysis in rheumatoid arthritis].

In order to clarify the pulmonary involvement in rheumatoid arthritis (RA), bronchoalveolar lavage (BAL) was performed in 52 RA patients, in conjunction with pulmonary function test (PFT) and high-resolution CT (HRCT) of the chest. The results were as follows: 1. Out of nine RA patients with no evidence of lung involvement on HRCT, six (66.7%) showed abnormal differentials of the cells obtained through BAL. 2. RA patients with advanced interstitial lung disease on HRCT had significantly higher BAL fluid (BALF) cellular concentrations, increased percentage of BALF neutrophils and decreased BALF CD 4/CD 8 ratio, as compared with those with no or mild lung involvement. 3. In the non-smoking RA patients who also demonstrated no obstructive patterns on PFT, positive correlations were observed between %VC and the BALF CD4/CD 8 ratio (R = 0.481) as well as the BALF CD4+Leu8- (helper T) cell ratio (R = 0.497). On the other hand, a negative correlation was detected between %VC and the BALF CD8+CD11b- (cytotoxic T) cell ratio (R = -0.533). 4. In those with the increased percentage of BALF eosinophils and/or with increased BALF CD4/CD8 ratio, V25/Ht was depressed significantly, as compared with other patients. Likewise, those with severely depressed value of V25/Ht tended to have significantly elevated BALF CD4/CD8 ratio, as compared with other patients with normal V25/Ht value. Thus, through these detailed studies of BAL cellular differentials and BALF lymphocyte subsets, the diversity of pulmonary involvement was well demonstrated in RA.

Aged↗
PubMed1993

[TSH receptors and signal transduction].

The TSH receptors constitute one of the main part of the signal transduction in thyroid cells and are the main biochemical targets in pathological changes. Recent molecular cloning of the TSH receptor and site-directed mutagenesis experiments have provided new evidence. It is well-established that TSH activates the cAMP cascade. Recent evidence however suggests that TSH can also activate the PIP2 cascade, but not anti-TSH receptor antibody. Specific alpha-subunits of the GTP binding protein modulate the stimulation of both pathways. Moreover, the thyroid diseases linked to the mutation of the GTP binding protein are seen. Although the TSH action in thyrocytes, through both pathways, are distinct, they are too complicated to classify clearly. The mechanism of the TSH stimulating pathway and the TSH function in thyrocytes are reviewed.

Cloning, Molecular↗
PubMed1993

Repeated canine herpesvirus (CHV) reactivation in dogs by an immunosuppressive drug.

To examine the possibility of repeated reactivation of canine herpesvirus (CHV), 2 serial treatments with the corticosteroid drug prednisolone (PD) were given at different periods following oral-nasal infection of pups and adult dogs. CHV was not recovered from infected, untreated dogs or from uninfected, treated controls. Viral reactivation of CHV, without clinical signs, was induced twice in 2/3 adults and in 2/3 pups treated at intervals that ranged from 1 to 3 months following the initial infections. Highest viral titers were obtained from nasal swab samples, with lower titers found in the oral pharynx, penis or vagina. In some, but not all dogs, the infectivity titers of the nasal secretion samples were higher after the initial prednisolone treatments than after the second treatments. The duration of viral shedding after the second series of steroid treatments also was shorter than the shedding period following the initial reactivations. The results presented here suggest that latent CHV occurs in both pups and adults dogs following infection and that active infections, with viral shedding, may occur repeatedly for prolonged, but undetermined, periods.

Age Factors↗
PubMed1993

[Influence of bilateral stellate ganglion block on hemodynamics].

This study was designed to investigate the influence of bilateral stellate ganglion block (SGB) on hemodynamics in 15 mongrel dogs. Following general anesthesia, each dog received SGB with 1.5% mepivacaine. Cardiovascular effect of bilateral SGB was assessed by measuring mean artery pressure (MAP), heart rate (HR), cardiac output (CO), right atrial pressure (RAP), mean pulmonary artery pressure (MPAP), pulmonary capillary wedge pressure (PCWP) and common carotid arterial blood flow (CCAF). These were measured directly by a Swan-Ganz catheter and ultrasonic blood flow meter, during the first 15 minutes after SGB. A decrease of MAP and HR was observed after bilateral SGB. CO decreased for 13% compared with the control value. However, this change was not statistically significant. There was a significant increase in the bilateral CCAF, but the degree of the increase of CCAF was greater after unilateral SGB than after the bilateral SGB.

Animals↗
PubMed1993

Virus reactivation in bitches with a medical history of herpesvirus infection.

Virologic and pathologic investigations were done on prednisolone-treated bitches with a history of canine herpesvirus (CHV) infection. Reactivation of CHV was demonstrated in 5 Beagle bitches after daily administration of 600 mg of prednisolone for 5 days. The reactivation was confirmed in 4 of 5 bitches. Canine herpesvirus was recovered from nasal, oral, vaginal, and ocular secretions on the 5th to 21st days after initiation of treatment with prednisolone, and also from nasal mucosa and tonsil tissues. Results indicated that latent CHV infections develop and that the virus may be reactivated, without clinical signs, in dogs with a history of CHV infection.

Abortion, Veterinary↗
PubMed1993

[Prognostic judgment of fulminant hepatitis by measurement of hepatosplenic volume ratio by computed tomography].

The liver and spleen volume ratio (S/L ratio) was estimated with X-ray computed tomography and evaluated by comparison with the prognosis in 10 patients with fulminant hepatitis. S/L ratio of control group (n = 10) was 0.122 +/- 0.026 (mean +/- SD), that of the alive group with fulminant hepatitis (n = 5) was 0.112 +/- 0.021, and that of the dead group (n = 5) was 0.308 +/- 0.136. There is a significant difference between S/L ratio of control group and that of the dead group with fulminant hepatitis. The rise of S/L ratio on the patients with fulminant hepatitis reflects the liver atrophy or splenomegaly and the prognosis was poor. The prognosis of the patients with fulminant hepatitis, whose S/L ratio indicated the near value of control group, was good. The measurement of S/L ratio by computed tomography was considered to be useful to evaluate the prognosis of fulminant hepatitis.

Adult↗
PubMed1993

[Clinical study of rheumatoid interstitial lung disease evaluated by high resolution CT].

High resolution computed tomographic (HRCT) scans were obtained in 215 patients with rheumatoid arthritis to assess pulmonary fibrosis (PF). We classified the HRCT appearances as five-point scale (0-4) based on the degrees of PF. The results were as follows: 1. We found 117 cases (54.4%) of PF on HRCT. 2. Patients with PF (grade 1-4) showed significantly increased leucocyte cell counts and significantly worsened pulmonary function test than patients without PF (grade 0). 3. Patients with advanced articular involvement had significantly higher prevalence of PF than others without them. 4. Patients who were previously or currently receiving gold sodium thiomalate (GST) injection or administration of methotrexate had higher prevalence of PF than others. However, patients who were receiving long term GST therapy (1 year long or sigma 1000 mg) had slightly lower prevalence of PF than others. This finding suggests that dose-dependent lung injury is not related to GST therapy. 5. Patients with advanced PF (grade 3, 4) had high prevalence of male sex, smoker, extraarticular manifestation.

Adolescent↗