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Biomedical subjects

K Yuasa

Publications and source records attributed to K Yuasa.

At least 91 records · Page 5Linked to original sources
PubMed1995

[Gene technology to overproduce the enzymes useful as diagnostic reagents].

We cloned the genes encoding the microbial enzymes described below and discussed the possibility as the diagnostic reagents: Creatinase(CR) and sarcosine oxidase(SOX) are useful for a diagnostic measurement of creatinine in combination with creatinase. Bacillus sp. B-0618 produces both CR and SOX enzymes when grown in the presence of an inducer, choline chloride. We cloned these two genes encoding CR and SOX by using recombinant DNA techniques. We found that the SOX-encoding gene is located upstream from the CR-encoding gene. When the CR- and SOX-encoding genes were independently inserted into the pUC-based vector and introduced into Escherichia coli, the transformants produced 15.5-fold more CR and 50-fold more SOX than Bacillus sp. B-0618, respectively, in the absence of the inducer. Although the Bacillus SOX is a flavoprotein, we created an FAD-free SOX by site-directed DNA mutagenesis. The mutant protein no longer expressed the SOX activity. Cholesterol esterase is useful for a diagnostic measurement of total cholesterol in combination with cholesterol oxidase. We cloned a gene encoding the cholesterol esterase enzyme. When the gene was introduced into the non-producing Streptomyces strain, the transformant produced the cholesterol esterase. Phospholipase A2 is a diverse family of enzymes that hydrolyze the sn-2 fatty acyl ester bond of phosphoglycerides producing free fatty acids and lysophospholipids. The enzymes are present in pancreatic juice and in the venoms of snakes and bees, where they serve digestive functions.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1995

[Sex cord/stromal tumor of the testis: a case report].

We herein report a case of sex cord/stromal tumor of the testis. A 28-year-old man was admitted to our hospital with the chief complaint of painless swelling of the left scrotal contents. On examination, gynecomastia or swelling of superficial lymph nodes was not observed. With a diagnosis of left testicular tumor, left high orchiectomy was performed. Gross examination of the specimen demonstrated a mass measuring 20 x 18 x 14 mm within the testis. On the cut surface, the tumor was gray and was associated with focal hemorrhage and necrosis. The spermatic cord and epididymis were not involved by the tumor. Microscopically, the tumor demonstrated a mixed pattern consisting of, we thought, areas of Leydig-like cells as well as areas of Sertoli-like cells showing mild atypia. Without further treatment, the patient has remained free from the disease for over fifteen months since the operation. Fifty eight cases of sex cord/stromal tumor of the testis have been reported in the Japanese literature, but sex cord/stromal tumors, other than pure Leydig cell tumor or Sertoli cell tumor, are very rare. Only 4 cases have been reported including our case.

Adult↗
PubMed1995

[Foamy alveolar macrophages in various lung diseases, and their origin in rabbit lungs].

The present studies were done to clarify the significance of foamy alveolar macrophages (FAM) in lung diseases, and the mechanism of the production of macrophages in rabbit lungs. Human subjects consisted of 18 normal volunteers (NV) and 47 patients with lung disorders: chronic bronchitis (CB), 7 cases; pulmonary fibrosis (PF), 8 cases; old pulmonary tuberculosis (OPT), 7 cases; lung cancer (LC), 20 cases; and bronchiectasis (BE), 5 cases. In each case, over 30 macrophages in the BALF were observed by transmission electron microscopy. There were no significant differences in the percentage of FAm in the BALF among NV, CB, and PF. Furthermore, OPT and LC were not significantly different. Many more FAM were seen in OPT and LC than in NV, CB, and PF (p < 0.005). The percentage of FAM obtained from BE was much higher than that from OPT and LC (p < 0.005). These results suggest that the grade of foamy change in macrophages differs among lung diseases. Three groups of rabbits were studied. Group I rabbits (n = 6) were control, Group II rabbits (n = 6) underwent bronchial clamping, and Group III rabbits (n = 6) underwent complete replacement of blood with saline. The number of macrophages and type II cells was much greater in Group II rabbits than in Group I rabbits. In Group III rabbits, the number of macrophages was lower than in Group I rabbits. In Group III rabbits, vacuole-like structures were seen in the cytoplasma of type II cells, but not from in macrophages. These findings suggest that anoxia and blood flow are important for the appearance of macrophages in alveolar space. Group III rabbits had few alveolar macrophages. Therefore, alveolar macrophages may be derived from monocytes in blood.

Aged↗
PubMed1994

(1-->3)-beta-D-glucan in indoor air, its measurement and in vitro activity.

The underlying mechanisms of the biological activity of (1-->3)-beta-D-glucan was investigated using macrophages from guinea pigs or mice. The results showed that these cells expressed (1-->3)-beta-D-glucan specific receptors on their surface, and that the release of TNF-alpha from cells was modulated by the presence of (1-->3)-beta-D-glucan.

Air Pollution, Indoor↗
PubMed1994

Evaluation of the therapeutic effect of TAE on primary liver cancer.

The therapeutic effect of transcatheter arterial chemoembolization (TAE) performed on 31 patients with primary liver cancer was evaluated using the following procedures: (1) the alpha-fetoprotein (AFP) reduction rates and prognoses were analyzed according to the tumor reduction rates (TR), and (2) the AFP reduction rates and prognoses were also analyzed according to the tumor necrosis rates (TN) estimated by regarding every region with Lipiodol retention as being necrotic. The following results were obtained. The AFP level was 400 ng/ml or higher in 15 patients (48%). Their AFP reduction rates were as favorably high as 65.4%-99.8% (mean, 88.1%), and the AFP level was normalized in 3 patients. The cumulative survival rates after the initial treatment were relatively high, i.e., 78.4% in the 1st year, 58.1% in the 2nd year, and 38.7% in the 3rd year. These results suggested the effectiveness of the TAE treatment undertaken in this study. Regarding the TR, the tumor was reduced in size by 50% or more in only 5 patients (16%), and most patients had a TR of less than 25%. On the other hand, the majority, 25 patients (81%), had a TN ranging between 50% and less than 100%, including 7 who had a TN ranging between 50% and less than 90% and 18 who had a TN ranging between 90% and less than 100%. There was no significant correlation between the AFP reduction rate and the TN or TR. Regarding evaluation of the cumulative survival rates by TR and TN, the 1-year survival rate was lower in patients having a TR of less than 25% than in those having a TR of 25% or more. Patients having a TN of less than 50% showed a poor outcome as compared with those having a TN of 50% or more. Although the TR was found to be less than 50% in a majority of the patients when the therapeutic effect of TAE on the liver cancer was evaluated according to the TR, many of these patients showed a good outcome. Thus, the conventional efficacy evaluation, in which a tumor reduction of 50% or more is considered to be effective, should be reconsidered. On the other hand, the TN was found to be 50% or more in most of the patients, suggesting the necessity of a more detailed classification of TN. In relation to the survival rate, patients having a TN of less than 50% showed a poor outcome.

Adult↗
PubMed1994

T1-weighted images with ECG gating using partial flip angle spin-echo imaging.

ECG-gated spin-echo imaging can reduce vascular artefacts compared with spin-echo scans without gating. However, this method produces poor T1-weighted images because the repetition time (TR) is limited by the heart rate. We investigated the value of low flip angle spin-echo imaging for increasing T1-dependent contrast when using ECG gating. Using computer simulation, the predicted contrast increased with decreasing the flip angle, and the effect was almost saturated at a flip angle of around 40 degrees. With the application of this flip angle, the identical image contrast as a T1-weighted image (TR = 400 ms) can be obtained within the heart rate range of 65 to 75 beats/min. For clinical evaluation, the tissue contrast index values ((signal intensity in the lesion-signal intensity in the muscle)2 x 100/signal intensity in the muscle) obtained by conventional spin-echo and low flip angle spin-echo imaging were compared in 17 patients. The contrast index of low flip angle spin-echo images (74.0 +/- 52.0) was significantly higher than that of conventional spin-echo images (40.9 +/- 35.9). Thus, ECG-gated low flip angle spin-echo imaging provided better T1-dependent contrast than conventional ECG-gated spin-echo imaging. This method may be especially useful for Gd-DTPA-enhanced magnetic resonance imaging.

Aged↗
PubMed1994

Bird droppings contain endotoxin and (1-->3)-beta-D-glucan.

Samples of bird droppings were collected and the amount of endotoxin and (1-->3)-beta-D-glucan in these was determined using a specific Limulus assay. All samples contained these agents and calculations on airborne levels demonstrated that doses at risk for inflammation and allergic alveolitis were present. Endotoxin and (1-->3)-beta-D-glucan should be considered in investigations on lung disease induced by bird droppings.

Alveolitis, Extrinsic Allergic↗
PubMed1994

Increased attenuation in odontogenic keratocysts with computed tomography: a new finding.

An increased attenuation area (IAA) is sometimes seen in the cystic cavity of odontogenic keratocysts (OKCs) on CT scans. The significance of IAA was compared radiologically and histologically in 26 cysts in which a provisional diagnosis of OKC had been made. First, the presence of IAA in the cystic cavity was assessed. Then, relationship between the presence of IAA and data obtained from the cysts, including the CT and histological findings and the visual appearance of the cyst contents, was evaluated. An IAA was frequently seen in large multilocular cysts. There was no relationship between the presence of IAA and aggressive features of the cyst on CT or the cyst contents. Histologically, subepithelial inflammation was often observed in the cysts with IAA. In order to ascertain whether the IAA was due to the keratin mass, a CT scan of a bundle of hair in a water bath was performed and shown to have a similar density. Our study demonstrated that IAA in cystic cavities results from desquamated keratin. Since this seems to occur in long-standing or inflamed multilocular OKCs, it could be used as a significant finding in the diagnosis of OKC.

Adolescent↗
PubMed1994

Quantitative analysis of masticatory muscles using computed tomography.

Quantitative information on the normal size range of the masticatory muscles needed for successful treatment of facial asymmetry is sparse. Our purpose in this study was to define morphological indicators for the volume of the masticatory muscles on CT. Cross-sectional areas and volumes of the masseter and medial pterygoid muscles were measured from CT scans of 65 patients. The muscles were scanned from origin to insertion and the maximum cross-sectional area (MCSA) and its location together with the total volume were determined. The mandibular foramen was used as a landmark to determine the location of MCSA. The location of MCSA of masseter muscle was centred 8 mm above the mandibular foramen, and that of medial pterygoid muscle at the foramen. The MCSA of both muscles was highly correlated with volume suggesting that this parameter might serve as an indicator of their volume. Knowledge of the location of the MCSA would facilitate its measurement and so reduce radiation exposure. There was a positive correlation between the two muscles for both volume and MCSA. This finding could be relevant for future studies of the relationship between the morphology, biomechanics and pathology of the masticatory muscles.

Adult↗
PubMed1994

[A study on the dosage of carboplatin for bronchial arterial infusion in combination with radiation therapy].

Radiation therapy holds an important position as one of the multidisciplinary methods of treating lung cancer (non-small cell carcinoma). As a result of the development of platinum preparations such as cisplatin (CDDP) and wide use of digital subtraction angiography (DSA), selective bronchial arterial infusion (BAI) therapy made possible more effective use of anti-lung cancer drugs. The use of radiation therapy in combination with BAI is now recommended as a more effective method. Meanwhile carboplatin (CBDCA) has recently been developed as a second generation platinum preparation with less side effects, and is being used for BAI, too. However, the maximum tolerated dose (MTD) of CB DCA for BAI to be used in combination with radiation therapy is not known yet. We, therefore, carried out a phase-study to determine MTD of CBD CA for combination with radiation therapy. The results show that the MTD of CBDCA is 400 mg/m2, and that clinically recommendable infusion limit is 350 mg/m2. In an angiographic study performed at the same time, a plural number of tumor affected blood vessels were found in 81.3% of the patients with lung cancer. Therefore, infusion of a drug for such patients should be carefully applied.

Aged↗
PubMed1993

Multimodality imaging of cervicofacial actinomycosis.

Actinomycosis is an uncommon chronic disease usually caused by Actinomyces israelii. It affects the soft tissue mainly but sometimes spreads to involve salivary glands, bone, or even the skin of the face and neck. Five cases have been seen in our department. Several imaging modalities were used to assist in making the diagnosis. The cases are presented and the literature reviewed. Ultrasonography was found to be a useful diagnostic tool especially in developing the differential diagnosis.

Actinomycosis↗
PubMed1993

Computed tomography of the jaws in familial adenomatosis coli.

Familial adenomatosis coli is known to be associated with tooth impactions, odontomas, and osteomas. Three cases were examined by panoramic radiography and computed tomography. Computed tomography was especially useful for detecting osteomas in the maxilla and also revealed a wavy cortical thickening in the mandible in one instance. The latter finding has been reported for other bones in the body but not previously for the mandible.

Child↗
PubMed1993

Quantification of occlusive and reperfused myocardial infarct size with Gd-DTPA-enhanced MR imaging.

The potential of Gd-DTPA-enhanced magnetic resonance imaging (MRI) for measuring infarct size was assessed in canine hearts. Twelve dogs underwent pre- and post-contrast MR imaging before and after recanalization. Infarct area was identified by triphenyltetrazolium chloride (TTC) staining of postmortal specimens in each case. Recanalization was complete in 10 dogs. High SI area was seen after reperfusion in nine of them; and it showed low signal intensity before reperfusion in seven of them. Two dogs were killed during reperfusion period: neither of them showed a low SI area before reperfusion. Necrotic regions were confirmed by TTC staining in seven of 12 dogs. Both the visual and quantitative assessment (n = 7) indicated that the extent of the low SI area before reperfusion was approximately the same as that of the necrotic region shown by TTC staining, while the high SI area seen after reperfusion was obviously larger than both the necrotic region and the low SI area on pre-reperfusion images. The correlation coefficient between low SI area and necrotic area was 0.98, and between high SI area and necrotic area was 0.80. These results suggest that Gd-DTPA-enhanced MRI may be useful for quantification of infarct size in occlusive myocardial infarction but it may overestimate in reperfused one.

Animals↗
PubMed1993

Evaluating coronary reperfusion during acute myocardial infarction in a canine model by gadolinium-DTPA-enhanced magnetic resonance imaging.

In previous studies, magnetic resonance imaging (MRI) using contrast agents was found to be useful in distinguishing reperfused infarcts from nonreperfused infarcts. However, there have been only a few detailed studies using consecutive MR images for the assessment of myocardial reperfusion during an acute myocardial infarction and also no studies have been performed using a percutaneous transluminal coronary occlusion model (closed chest model). We induced acute myocardial infarction in dogs by occluding and then reperfusing the coronary artery with a balloon catheter. ECG-gated MR images were taken using the spin-echo technique before and after Gd-DTPA injection during both coronary artery occlusion and after reperfusion. We defined the intensity ratio (IR) as the signal intensity at the ischemic area divided by that at the nonischemic area on MR images and compared each image by the IR. Without Gd-DTPA, there was no difference between infarcted and normally perfused myocardium. Infarcted myocardium had a low signal intensity (IR = 0.68 +/- 0.14) soon after Gd-DTPA injection. This difference diminished with time. After reperfusion the infarcted myocardium had a high signal intensity (IR:1.76 +/- 0.34). We conclude that Gd-DTPA- enhanced MRI can distinguish reperfused from nonreperfused infarcts soon after Gd-DTPA administration.

Animals↗
PubMed1993

Analysis of maxillary sinusitis using computed tomography.

Odontogenic maxillary sinusitis can be defined as sinusitis induced by a dental lesion. We examined the CT findings of 68 patients with maxillary sinusitis in order to differentiate between inflammation of sinus origin and inflammation of dental origin. Maxillary sinusitis was classified into four types according to clinical symptoms, history and conventional radiographic findings: type 1, simple sinusitis; type 2, odontogenic sinusitis; type 3, mixed sinusitis; type 4, slight sinus abnormality with a dental lesion. The relationship between the type of maxillary sinusitis and CT findings was analysed. Type 1 sinusitis exhibited severe pathological changes in both mucosa and bone which often extended into the nasal cavity and other paranasal sinuses. Type 2 sinusitis exhibited localized pathology on the unilateral antral floor. Type 3 sinusitis exhibited severe pathology characteristic of type 1 combined with type 2 sinusitis. Type 4 sinusitis could be differentiated by the CT findings into type 1 or type 2 sinusitis. The classification of sinusitis in this manner has implications for treatment planning, and CT should therefore be performed when conventional radiography does not provide sufficient information.

Female↗
PubMed1992

[Low flip angle spin-echo MR imaging to obtain better Gd-DTPA enhanced imaging with ECG gating].

ECG-gated spin-echo imaging (ECG-SE) can reduce physiological motion artifacts. However, ECG-SE does not provide strong T1-weighted images because repetition time (TR) depends on heart rate (HR). We investigated the usefulness of low flip angle spin-echo imaging (LFSE) in obtaining more T1-dependent contrast with ECG gating. in computer simulation, the predicted image contrast and signal-to-noise ratio (SNR) obtained for each flip angle (0-180 degrees) and each TR (300 msec-1200 msec) were compared with those obtained by conventional T1-weighted spin-echo imaging (CSE: TR = 500 msec, TE = 20 msec). In clinical evaluation, tissue contrast [contrast index (CI): (SI of lesion-SI of muscle)2*100/SI of muscle] obtained by CSE and LFSE were compared in 17 patients. At a TR of 1,000 msec, T1-dependent contrast increased with decreasing flip angle and that at 38 degrees was identical to that with T1-weighted spin-echo. SNR increased with the flip angle until 100 degrees, and that at 53 degrees was identical to that with T1-weighted spin-echo. CI on LFSE (74.0 +/- 52.0) was significantly higher than CI on CSE (40.9 +/- 35.9). ECG-gated LFSE imaging provides better T1-dependent contrast than conventional ECG-SE. This method was especially useful for Gd-DTPA enhanced MR imaging.

Contrast Media↗
PubMed1992

Acute pulmonary toxicity of inhaled beta-1,3-glucan and endotoxin.

The number of inflammatory cells was studied in lung walls and airways after inhalation of endotoxin or beta-1,3-glucan. In the water unsoluble form, beta-1,3-glucan caused a delayed response in terms of a decrease in macrophages and lymphocytes in the lung wall, 1 to 7 days after exposure but no invasion of neutrophils into the airways. When solubilized in 0.02 N NaOH, the cell response was the same as that observed after exposure to endotoxin.

Administration, Inhalation↗