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Biomedical subjects

K Doi

Publications and source records attributed to K Doi.

At least 703 records · Page 39Linked to original sources
PubMed1986

Cloning and expression in Escherichia coli of the gene for an Arthrobacter beta-(1----3)-glucanase.

When inserted in the correct orientation at the BamHI site of plasmid YRp7, an 8.6-kilobase BamHI fragment of Arthrobacter sp. strain YCWD3 DNA gave Escherichia coli HB101 cells harboring the recombinant plasmid pBX20 the ability to lyse bakers' yeast cell walls or bakers' yeast glucan in agar medium. An extract of the transformed E. coli cells contained an endo-beta-(1----3)-glucanase with the same activity pattern as that of glucanase I produced by Arthrobacter sp. strain YCWD3. Although part of the glucanase activity was contributed by apparently defective molecules, two protein species were found which had high lytic activity on yeast cell walls and adsorbed to microcrystalline cellulose, and both had a single constituent polypeptide with a molecular weight of about 55,000, as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. In these properties the protein species were indistinguishable from those glucanase I protein species of Arthrobacter sp. strain YCWD3 which we believe are nearly the intact molecule. We conclude that the cloned fragment of Arthrobacter sp. strain YCWD3 DNA contains the structural gene for glucanase I. A recombinant plasmid obtained by subcloning a PstI fragment of pBX20 into pBR322 caused the transformed E. coli cells to produce apparently defective glucanase molecules only. This observation serves as additional supporting evidence for our conclusion.

Arthrobacter↗
PubMed1986

Digital radiography of subtle pulmonary abnormalities: an ROC study of the effect of pixel size on observer performance.

Forty conventional radiographs with examples of mild interstitial infiltrates and subtle pneumothoraces and 40 normal studies of the chest were selected and digitized, with pixel sizes of 1.0, 0.5, 0.2, and 0.1 mm. Observer performance tests were carried out using receiver operating characteristic analysis. Conventional radiographs and digitized images were compared. The results indicate that, in such cases, diagnostic accuracy increases significantly as the pixel size is reduced, at least to the 0.1-mm level. We conclude that, for digital systems using screen-film or similar image receptors, use of a pixel size substantially larger than 0.1 mm may result in some loss of diagnostic accuracy.

Analog-Digital Conversion↗
PubMed1986

Digital radiographic imaging system with multiple-slit scanning x-ray beam: preliminary report.

A digital imaging system that employs a novel scanning x-ray tube, a multiple-slit assembly (MSA), and an image intensifier (II)-TV digital system is described. Use of the MSA can increase x-ray utilization by a factor of 100 over that obtained with single-slit systems. Scatter and veiling glare can be reduced substantially by synthesizing the final image from a number of multiple-slit images, resulting in improvement in contrast sensitivity. An experimental prototype system consisted of a conventional x-ray tube and an II-TV digital system used in conjunction with mechanical scanning of the MSA. Attenuation curves measured with an aluminum stepwedge showed that scatter and veiling glare were eliminated by this approach. Reconstructed images of phantoms were superior to images obtained with conventional wide-beam exposure. Physical parameters related to design of the scanning x-ray tube and a digital system for acquiring images of the chest are discussed.

Humans↗
PubMed1986

Mouse strain difference in bile duct lesions induced by swine serum injections.

The mouse strain difference in bile duct lesions was studied on male A/J, BALB/c, C57BL/6, C3H/He, DBA/2 and DDY mice 4 weeks old given intraperitoneal injections of swine serum (0.05 or 0.2 ml per mouse) twice a week for 4 weeks. The hepatic lesions were restricted to the portal tract. Biliary epithelial cells showed hypertrophy and hyperplasia, and eosinophilic and homogeneous or needle-shaped material appeared in the cytoplasm of such hypertrophied epithelial cells and in the ductular lumen. Around these damaged biliary epithelia, eosinophil leukocyte and plasma cell infiltration with proliferation of collagen fibres was commonly detected. These changes became more apparent with increasing size of bile duct. Such histopathological characteristics of hepatic lesions were essentially the same in all strains, but the severity showed a clear strain difference: the lesion was marked in the DDY, A/J and BALB/c strains, moderate in C3H/He and slight in C57BL/6 and DBA/2. A high production of anti-swine-serum antibodies associated with a marked increase in the number of mouse IgG-producing lymphocytes in the spleen was detected in the strains showing the marked hepatic lesions.

Animals↗
PubMed1986

Histopathology of streptozotocin-induced diabetic DBA/2N and CD-1 mice.

Histopathological examinations were carried out on female DBA/2N and CD-1 mice which were autopsied 4 and 12 weeks after six daily intraperitoneal injections of streptozotocin (SZ). Histopathological changes related to SZ treatment were found in the pancreas, liver and kidneys. Little difference was observed between the two strains in the histological changes of the pancreas (a decrease in size of the islets, and degranulation and a decrease in the number of B cells) and liver (hypertrophy of hepatocytes and cytoplasmic invagination into hepatocyte nuclei). With regard to the changes in the kidneys, DBA/2N mice showed characteristic inclusions positive to periodic acid-Schiff reagent in the distal tubule epithelial cells, while CD-1 mice showed remarkable luminal dilatation and epithelial cell deformation of distal tubules. SZ-induced diabetes had no influence on the development of spontaneous cardiovascular lesions in DBA/2N mice under the present experimental conditions.

Animals↗
PubMed1986

Development of spontaneous tongue calcification and polypoid lesions in DBA/2NCrj mice.

Calcified tongue lesions were observed in 4- to 8-week-old DBA/2NCrj mice, the highest frequency being reached at 6 weeks of age. Calcification was initially observed in the superficial longitudinal muscles and these lesions were distributed segmentally under the dorsolateral mucous epithelium in the middle portion of the lingual body. After calcification, marked inflammation was observed in the same lesion. Finally, the swollen tissue elevated the covering mucous epithelium and produced polypoid lesions.

Animals↗
PubMed1986

Development of heart and aortic lesions in DBA/2NCrj mice.

The development of heart and aortic lesions was investigated in 3- to 8-week-old DBA/2NCrj mice. In the heart, small foci of myocardial calcification and severe calcification with subsequent inflammation were observed. Severe lesions were restricted to the myocardium below the right ventricular epicardium. Small foci of myocardial calcification were found from 4 to 8 weeks of age with almost the same frequency. The incidence of severe calcification showed a drastic increase between 6 and 7 weeks of age. Aortic lesions were observed from 3 weeks of age and characterized by focal calcification of the smooth muscle cells and elastic laminae. The frequency of aortic calcification was about 50% and not age-related.

Animals↗
PubMed1986

Multiple endocrine neoplasia with Cushing's syndrome due to paraganglioma producing corticotropin-releasing factor and adrenocorticotropin.

A male patient with corticotropin-releasing factor (CRF) and adrenocorticotropin (ACTH)-producing syndrome is described. Soon after being referred to us the patient developed pneumonia, anaemia, oedema and respiratory distress, and died on the 24th day after admission. Autopsy and histology revealed that he had a rare type of multiple endocrine neoplasia (type 1 + paraganglioma) with a mediastinal paraganglioma, parathyroidal hyperplasia, pancreatic islet cell adenoma, duodenal multiple carcinoid tumours and adrenocortical nodular hyperplasia. It was not possible to examine the pituitary. The paraganglioma contained a large amount of immunoreactive (IR)-CRF (606 ng/g wet weight), IR-ACTH (59.4 ng/g wet weight), IR-human proopiomelanocortin n-terminal (1-76) peptide (hNT, 156.8 ng/g wet weight) and IR-beta-lipotropin (beta-LPH, 146.9 ng/g wet weight). The major IR-ACTH, beta-LPH and IR-hNT were eluted at ACTH-(1-39), beta-LPH and hNT marker positions, respectively. Big ACTH was not detected. IR-CRF eluted at the human CRF marker position on Sephadex G-75 chromatography and high performance liquid chromatography (HPLC). The IR-CRF fraction from the HPLC showed CRF bioactivity which paralleled that of synthetic human CRF in monolayer cultured rat anterior pituitary cells. Our results suggest that not only ACTH but CRF produced by the paraganglioma was responsible for the patient's Cushing's syndrome.

Adrenocorticotropic Hormone↗
PubMed1986

Evaluation of uneven distribution of VA/Q ratio from data on exchange of respiratory gases.

A new approach has been developed for evaluating uneven distribution of ventilation/perfusion ratio, VA/Q, based on a two-compartment model with a reciprocal VA/Q relation. The VA/Q ratios were expressed by mu . (1-rho)/rho and mu . rho/(1-rho), where mu and rho were referred to as the "ideal" VA/Q ratio and unevenness factor, respectively. During steady state breathing, arterial blood was analyzed for PO2 and PCO2, and end-tidal PCO2 as well as the gas exchange ratio, R, was measured. After steady state breathing a rebreathing experiment was performed, and the arterial-venous O2 content difference, (a-v)CO2, was measured, and then, multiplying it by R, the venous-arterial CO2 content difference, (v-a)CCO2, was obtained. Referring to these values the mixed venous PO2 and PCO2 were estimated from arterial PO2 and PCO2, using the O2 and CO2 dissociation curves. The VA/Q line and iso-R line were drawn to find mu, and further, total arterial, and alveolar PO2 and PCO2 of the two-compartment model were computed by changing both rho and the mixing weight factor, phi. The phi value was determined so as to make the above PO2-PCO2-locus pass through the measured arterial PO2 and PCO2. The rho value was selected so that the computed alveolar PCO2 fitted to the end-tidal one. The experiments were performed on 8 normal subjects in normoxia and hyperoxia with PIO2 245 Torr. The mean phi values in normoxia and hyperoxia were 0.50 and 0.56, respectively. The mean rho values in normoxia and hyperoxia were 0.438 and 0.428, respectively. The VA/Q ratio was decreased in hyperoxia because of a decrease in VA value.

Carbon Dioxide↗
PubMed1986

[Perceptual categorization of emotional expression cued by ones back posture].

Subjects looked at 8 mm motion pictures of the bodily movement from rear view perspective of male and female communicators, who faced to emotionally-toned scenes. If the subjects detected some sign of emotional expression, they rated the relevance of expression on five point scale. Varimax rotated factor analysis yielded three factors: F1 rejection-acceptance, F2 avoidance-approach, and F3 sadness. Rejection was categorized as expressions of anger, disgust, and contempt, while anger was categorized when a clenched fist with forward and extended arm were observed. Disgust and contempt were categorized when stationary posture was observed. Acceptance was categorized when the signs of affection, anticipation, and acceptance were observed. Avoidance was categorized when signs of fear and surprise were observed. A typical fear was categorized when signs of freezing was observed, surprise was categorized by stepping back, and sadness was categorized by crouching and self attachment.

Adult↗
PubMed1985

Functional latissimus dorsi island pedicle musculocutaneous flap to restore finger function.

Functional latissimus dorsi island pedicle musculocutaneous flaps were used to restore flexion or extension of the wrist and digits in four clinical cases. By retaining the fascial origin of the latissimus dorsi from the posterior crest of the ilium, the entire muscle was transferred without dividing its neurovascular pedicle and microneurovascular anastomoses. Its facial origin successfully reached the finger flexor or extensor muscles of the forearm. The latissimus dorsi muscle was sutured to the digital flexor tendons in three patients and connected to the extensor tendons in one patient. All transfers restored active finger flexion or extension.

Adult↗
PubMed1985

Fingerprint-like straight crystalloid microfilaments in lobular glomerulonephritis.

This 64-year-old male presented edema and proteinuria. With increasing renal insufficiency and persistent fever, he died 7 months after the onset of illness, complicated with terminal miliary tuberculosis. All the glomeruli showed sclerotic nodular lobulation and mesangial circumferential interposition with positive immunoglobulin and complement predominantly along the capillary, consistent with lobular glomerulonephritis (LGN) or terminal stage of membranoproliferative glomerulonephritis (MPGN). Electron microscopy revealed subepithelial straight crystalloid microfilaments in the amorphous deposits. These structures possibly represent IgG or its fragment as a component of immune complex crystallized in some particular condition.

Crystallography↗
PubMed1985

Elastofibroma of the greater omentum.

A rare case of elastofibroma developing in the greater omentum of a 76 years old woman was reported. The greater omentum was thickened in a plate-like shape to a size of 24 X 15 X 2 cm, and a firm mass as large as 5 X 4 X 3 cm was formed in a portion of the omentum. Granulomatous inflammation associated with the calcification was present in the center region of the mass. Collagen fibers and elastofibroma fibers were markedly proliferated around the granuloma. Fibrosis accompanied with the formation of elastofibroma fibers was observed not only around the granulomatous inflammatory focus but also throughout the thickened omentum. The elastofibroma fiber in this case lost its stainability to resorcin-fuchsin and orcein after 4 hours treatment with elastase. It may be inferred that not only mechanical stresses but also inflammatory stimuli contribute to the development of elastofibroma.

Aged↗
PubMed1985

Ultra-high-strip-density radiographic grids: a new antiscatter technique for mammography.

We conducted a comprehensive study on the application of ultra-high-strip-density (UHSD) grids to mammography for the improvement of image contrast. These UHSD grids have strip densities of 70 to 100 lines/cm. After investigating the performance of mammographic grids with various design parameters through Monte Carlo simulation studies, we made prototypes of UHSD grids having lead strip thicknesses of 20 to 37 micron, aluminum interspacer thicknesses of 80 to 120 micron, and grid ratios of 2 to 6. The UHSD grids can be placed inside the cassette without a Bucky tray and thus will not increase geometric unsharpness. The measured physical characteristics and the phantom images obtained confirmed our findings in the simulation studies. A 40 to 90% increase in contrast was achieved at Bucky factors of 2 to 3.5; these results are comparable with those from conventional antiscatter grid techniques in mammography. The potential usefulness of the UHSD grids was demonstrated in a preliminary clinical comparison of mammograms.

Equipment Design↗
PubMed1985

Dynamic and static phantoms for evaluation of digital subtraction angiographic systems.

Two types of phantoms were developed with which to evaluate the overall performance of digital subtraction angiography (DSA) systems. A dynamic phantom, called a "fish bone" phantom, consists of polyethylene tubes that simulate blood vessels with various lesions, such as stenoses, ulcers, and aneurysms. With this phantom, washout curves were obtained representing the relationship between iodine content and time. It will be useful for qualitative assessment of DSA images, evaluation of different image-processing schemes, and studies of blood flow analysis. A static phantom, called a "C-D" phantom, can be used for measurement of quantitative contrast-detail (C-D) diagrams and for daily monitoring of DSA systems. This was constructed of tubes of seven different diameters (2.15-0.28 mm) and 14 different concentrations of contrast medium (100%-1.1% Renografin-76 [meglumine and sodium diatrizoate]). The C-D diagrams were determined from an observer performance study using C-D phantom images obtained at four different DSA settings.

Angiography↗