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Biomedical subjects

N Sugimoto

Publications and source records attributed to N Sugimoto.

At least 145 records · Page 8Linked to original sources
PubMed1995

Mobility inhibition and nematocidal activity of asarone and related phenylpropanoids on second-stage larvae of Toxocara canis.

The in vitro effect of asarone, the nematocidal principle of the rhizome of Acorus calamus, on second-stage larvae of Toxocara canis is composed of two independent actions: one is a fast acting inhibition of the larval mobility and the other is a slow acting larvicidal action. Mobility of the larvae was rapidly inhibited when they were incubated with asarone. Dye exclusion assay revealed that larvae were alive at this stage, and their mobility was restored after the first inhibition, suggesting that this effect was temporary and reversible. However, when the mobility decreased again during prolonged incubation, the cellular viability of larvae disappeared, showing that they were killed by the compound. The above two-stage effect of asarone was almost identical in two geometrical isomers ((E)- and (Z)-asarone). Di- and tri-methoxypropenyl or propylbenzenes carrying two methoxy groups at a vicinal position on a benzene ring showed, more or less, a two-stage effect of this type. These two actions were suggested to be separable by an appropriate modification of the structure.

Allylbenzene Derivatives↗
PubMed1995

[A case of productive aspergilloma on the inner wall of a cavity, in which perbronchial fiberoptic bronchoscopy within the cavity was useful for the diagnosis and therapeutic evaluation].

A 45-year-old man complaining of bloody sputum was admitted. He had been treated for pulmonary tuberculosis since October 1988. He had bloody sputum in October 1989. His chest X-ray findings showed a cavitary lesion with a thickened and irregular wall in the right upper lobe. Fiberoptic bronchoscopy revealed white nodules on the cavity wall and the biopsy specimen from the nodule yielded a fungus granuloma. Aspergillus fumigatus was cultured from the sputum obtained after the bronchoscopy. Based on these findings, endobronchial aspergillosis and productive aspergilloma on the inner wall of a cavity was diagnosed. He was treated with oral anti-fungal drugs for 4 years. On chest X-ray films taken in June 1993, the cavity had enlarged, and the thickening and irregularity of the cavity wall had disappeared. Transbronchial fiberoptic bronchoscopy within the cavity showed whitish nodules and the cytology specimen obtained from the nodules by brushing yielded fungi, he was treated with oral itraconazol. Six months later, re-examination of the cavity revealed that the wall had become thinner and that the nodules on the inner wall had disappeared. This case illustrates the importance of bronchoscopy, in the diagnosis and evaluation of treatment of productive aspergilloma on the inner wall of a cavity.

Administration, Oral↗
PubMed1995

[Primary pulmonary malignant lymphoma of the T-cell type].

A 65-year-old woman was referred to our department because of an abnormal shadow on the chest roentgenogram. The chest roentgenogram showed infiltrative shadows in the right middle and lower lung fields. The chest CT scan showed non-segmental infiltration with a hazy margin and a clear air bronchogram in the right S8 area. A transbronchial aspiration cytology specimen showed atypical lymphocytes, and a transbrochial lung biopsy specimen showed infiltration by atypical lymphocytes. Malignant lymphoma was suspected from the results of the biopsy examination, and a right middle and lower lobectomy was done. The pathological findings showed proliferative atypical lymphocytes in the alveolar and interstitial areas. Malignant lymphoma (diffuse medium cell type by LSG classification) was diagnosed and an immunohistiochemical examination showed monoclonal proliferation of T lymphocytes, which were positive for T lymphocyte surface marker (UCHL-1). Therefore, we believe this was a case of primary pulmonary malignant lymphoma of the T-cell type.

Aged↗
PubMed1995

Interaction of oligonucleotides with a single stranded DNA binding site of RecA protein.

Model peptide Ile-Arg-Met-Lys-Ile-Gly-Val-Met-Phe-Gly-Asn-Pro-Glu-Thr- Thr-Thr-Gly-Gly-Asn-Ala-Leu-Lys-Phe-Tyr for a single stranded DNA (ssDNA) binding site of RecA protein has been synthesized and its interaction with some ssDNAs and ssRNAs has been investigated. Circular dichroism spectra showed that conformational change of the peptide by the addition of a ssDNA dACCTAGTC was much faster than that by the addition of a ssRNA rACCUAGUC. The addition of a neutral DNA or a 2'-5' linked oligonucleotide did not lead to the conformational change of the peptide.

Amino Acid Sequence↗
PubMed1995

Structure and stability of DNA containing alpha-deoxyadenosine.

The alpha-anomer of 2'-deoxyadenosine (alpha) is a major adenine lesion produced by hydroxyl radicals. This lesion was specifically incorporated in duplexes d(TGAGXGTAC).d(GTACNCTCA), where X = alpha and N = A, G, C, or T. The thermodynamic and structural perturbations introduced into DNA by alpha were assessed by UV-melting measurements and molecular mechanics calculations.

DNA↗
PubMed1995

Structure of translation initiation region of c-myc mRNA and thermostability of the c-myc mRNA/antisense ODN complex.

We enzymatically synthesized c-myc mRNA fragment containing the translation initiation (TI) region (36mer) and examined the structure by CD, 1H-NMR and RNaseV1 digestion. These study demonstrated that the c-myc mRNA fragment forms a hairpin structure at 37 degrees C. Six 15-mer antisense oligodeoxynucleotides(ODNs), which hybridize to the c-myc mRNA fragment were designed, and synhesized. Thermostabilities of the antisense ODNs-mRNA fragment complexes were examined. Antisense A (complementary to the c-myc mRNA from -9 to +6)-c-myc mRNA fragment complex had the highest melting temperature(Tm), and Antisense D (complementary to the c-myc mRNA from +1 to +15)-c-myc mRNA fragment complex had the most different Tm from a predicted Tm. Furthermore, Antisense D exhibited high inhibitory effect on HL60 cell proliferation, whereas Antisense A did not. The results suggest that the difference in the antisense effect is not simply due to the complex thermostability.

Cell Line↗
PubMed1995

Regulation of leadzyme (lead-dependent ribozyme) reaction by amino acids and rare earth ions.

Effects of rare earth ions and amino acids on a novel cleavage reaction of 10mer leadzyme (lead-dependent ribozyme) CUGGGAGUCC have been investigated. Cleavage yield of RNA substrate GGACC decreases GAGCCAG by the leadzyme was 7.4% for 20 min at 25 degrees C. The cleavage reaction was performed at 5 microM leadzyme, 250 nM substrate, 25 microM Pb2+, pH 7.5. Under the same reaction condition, the addition of 25 microM Nd3+ led to the increase of the yield from 7.4% to 39.8 %, although other divalent metal ions such as Mn2+ and Co2+ showed no effect on the yield. At 75 microM Pb2+, the yield decreased from 48.0 % to 15.0 % by the addition of 10 mM Arg, although the addition of 10 mM Lys did not affect the yield. These results indicate that the cleavage reaction by the leadzyme is regulated by the combination of metal ions and amino acids.

Amino Acids↗
PubMed1994

RNA/DNA hybrid duplexes with identical nearest-neighbor base-pairs have identical stability.

Energetic behaviors of eight pairs of RNA/DNA hybrid duplexes with identical nearest neighbors have been investigated by UV melting analysis. In the pairs with identical nearest-neighbor pairs, the melting curve traces at the same strand concentration were very similar. The average difference in stabilization energy of these pairs was 4%, which was about expected within experimental error. These results indicate that the nearest-neighbor model is valid for predicting the stability of RNA/DNA hybrid duplexes as well as RNA/RNA and DNA/DNA duplexes.

Base Composition↗
PubMed1994

Bordetella bronchiseptica dermonecrotizing toxin stimulates protein synthesis in an osteoblastic clone, MC3T3-E1 cells.

The effects of Bordetella bronchiseptica dermonecrotizing toxin on protein synthesis in an osteoblastic clone, MC3T3-E1 cells, were investigated. The rate of protein synthesis in the serum-starved cells was increased by the toxin after a latent period of about 4 h, and reached 2.5 times that of the control 24 h after addition of toxin. The toxin raised the level of protein synthesis even in actively proliferating cells. The stimulatory effect of the toxin on protein synthesis occurred earlier than other toxic events so far reported, such as the stimulation of DNA synthesis and the inhibition of osteoblastic differentiation, and was apparently dependent on the toxin concentrations over the range 0.05 ng ml-1 to 6.0 ng ml-1. Therefore, the stimulatory effect of the toxin on protein synthesis could be useful in determining the mode of action of the toxin.

Animals↗
PubMed1994

Tetanus toxin and Clostridium perfringens enterotoxin as tools for the study of exocytosis.

The role of calmodulin in exocytotic secretion was studied using digitonin-permeabilized bovine adrenal chromaffin cells to examine the effect of calmodulin directly introduced into the cells and using tetanus toxin as a specific inhibitor of exocytotic secretion. Addition of calmodulin to the permeabilized cells increased Ca(2+)-dependent norepinephrine release in a dose-dependent manner. The enhancement of release by calmodulin was specific to calmodulin: bovine serum albumin, actin, and caldesmon had no such effect. Enhancement of release by calmodulin occurred at Ca2+ concentrations of more than 10(-6) M and increased with an increase of Mg2+ concentration. The release of norepinephrine enhanced by calmodulin was inhibited by tetanus toxin. These results indicate directly that calmodulin plays an important role in exocytotic secretion from chromaffin cells. Exocytosis is known to occur by fusion of plasma membrane with limiting membranes of secretory vesicles following an increase in intracellular Ca2+. We used the enterotoxin of Clostridium perfringens type A as a specific tool to modify plasma membrane permeability to induce calcium influx. Multigranular exocytosis was recognized electron-microscopically in addition to the single-granular exocytosis in rat anterior pituitary cells and pancreatic acinar cells treated with the enterotoxin in the presence of extracellular Ca2+. The treatment with the enterotoxin did not induce any drastic change in the fine membrane structures of both types of cells. The enterotoxin-treated anterior pituitary cells and pancreatic acinar cells should provide a useful system for studying the molecular mechanism of fusion of membranes in exocytosis.

Adrenal Medulla↗
PubMed1994

Changes in hypothalamic temperature of rats after daily exposure to heat at a fixed time.

Rats were subjected to an ambient temperature (Ta) of 33 degrees C for ca. 5 h during the last half of the dark phase for 5, 14 or 28 consecutive days (heat-exposed rats, HE), while control rats were kept at a constant Ta of 24 degrees C. After the heat exposure schedule, the levels of hypothalamic temperature (T(hy)) as an index of body core temperature in the HE were significantly lower than those of the controls for 2-4 h in the last half of the dark phase. The low levels of T(hy) persisted during the specific period for 1, 3 and 6 days after the end of the 5-, 14- and 28-day heat exposure schedules, respectively. These results confirm that, in rats subjected to daily heat exposure for ca. 5 h at a fixed time per day, their T(hy) falls during the period when the rats were previously exposed to heat, and suggest that the duration of the specific T(hy) change observed after completing the heat exposure schedule depends on the length of the heat exposure schedule.

Animals↗
PubMed1994

A new method for automatic identification of coronary arteries in standard biplane angiograms.

A new computerized method for analyzing biplane coronary arteriograms was proposed. The method extracted the vessels in an image, detected branching points, and identified vessel segments according to their anatomical names. The method was applied to a pair of orthogonal projection images acquired in the right anterior oblique and left anterior oblique views. It recognized the corresponding vessel segments in the images and labeled them correctly by their anatomical names. For diameter measurement, a combined first and second derivative filter process was applied to the images along the skeleton lines of the extracted vessel segments. We also designed a method of representation in which vessel diameters measured in the two projection images could be displayed in a single image.

Cineangiography↗
PubMed1994

Limitation of detection and evaluation of coronary arterial stenosis by densitometry.

In coronary cineangiography, both X-ray absorption and light scatter in the image intensifier tend to degrade image quality, and so affect the accuracy of densitometric measurement of vessel diameter. To investigate this problem, we compared the accuracy and precision of the densitometric method and the edge detection method in the automated detection of stenosis in both vessel phantom and clinical studies. In the phantom study, the X-ray penetration was varied by altering the thickness of the model, and the change in the measured diameter obtained by each of the two methods was evaluated simultaneously. A difference of 5 mm in the thickness of the model was found to alter significantly (P < 0.01) measurement of the diameter obtained using the densitometric method, but not that obtained by the edge detection method. In the clinical part of the study, the accuracy of each method in the automated detection of coronary stenosis was evaluated. With respect to the detection of stenosis, the level of disagreement between the assessment of the 3 observers and what was detected by densitometry (22.8%) was 2.9 times higher than the disagreement between the observers' assessment and what was detected using the edge detection method (7.9%). When the background density of the coronary cineangiogram along the axis of the vessel was uneven, many vessel segments which had been evaluated as normal when edge-detection was used were evaluated as stenosed when densitometry was used. This study, then, demonstrates that the Lambert-Beer law does not apply in cases where the thickness of the subject varies in different locations along the axis of the same vessel. We therefore conclude that densitometry is not a reliable means of assessing coronary stenosis in such cases, due to veiling-glare and scatter, and recommend that it not be routinely used in the automated detection of coronary arterial stenosis.

Absorptiometry, Photon↗
PubMed1994

Estimation of 2-D blood flow velocity map from cine-angiograms: algorithm using overlapping block set and illustration of vortex flow in abdominal aneurysm.

To derive blood flow dynamics from cine-angiograms (CAGs), we have developed an image-processing algorithm to determine a two-dimensional blood flow velocity map projected on CAGs. Each image data of CAG is divided into a set of overlapping blocks, and it is assumed that the contrast medium in each block moves only to its 'adjacent blocks' between two serial frames. Based on this assumption, a 'fundamental equation' and the 'maximum flow constraints' are derived. These equations state the relationship between the volume of contrast medium in each block and the volume of contrast medium flowing from/to its 'adjacent blocks'. The volume of the flowing contrast medium is calculated using these relationships, boundary conditions and an additional 'smoothness constraint'. The blood flow velocities are estimated from the volume of the flowing contrast medium and are illustrated with a needle diagram. We applied our algorithm to an abdominal CAG (clinical data). The result showed a vortex flow in the abdominal aneurysm, which was consistent with visual inspection of the CAG movie and with the existence of thrombus in the aneurysm. Our algorithm may be a useful diagnostic tool to assess vascular disease.

Algorithms↗
PubMed1994

Persisting changes in the 24-hour profile of locomotor activity by daily activity restriction in rats.

Male Wistar rats were acclimated to cages with running wheels. Then, the running time of rats were limited to the last 3 (WR3) or 6 (WR6) h of the dark phase. After a 2-week activity restriction, the rats were again allowed access to the wheel freely. In the WR3 or WR6, wheel revolutions for the last 3 or 6 h of the dark phase was significantly greater after the activity restriction than before. The results suggest that, in rats, voluntary running limited to a fixed time daily alters the distributions of locomotor activity in a day, i.e., running activity increases during the period when the rats had been previously allowed to exercise.

Activity Cycles↗
PubMed1994

Pharmacokinetics of amlodipine and its occupancy of calcium antagonist receptors.

We characterized the occupancy of dihydropyridine (DHP) calcium antagonist receptors by amlodipine in spontaneously hypertensive rats (SHR) in relation to its pharmacokinetics. Oral administration of amlodipine (10 mg/kg) in SHR produced a significant (20-70%) decrease in the number of specific (+)[3H]PN 200-110 binding sites in cardiac tissues 0.5-18 h later, and the effect was greatest 3 h later. In these rats, there was little change in cerebral cortical (+)[3H]PN 200-110 binding. Occupancy of cardiac calcium antagonist receptors after oral administration of amlodipine correlated well with its plasma concentration. In vitro blockade of cardiac (+)[3H]PN 200-110 binding sites induced by amlodipine also persisted after the tissues were washed by centrifugation and suspension, whereas that induced by nifedipine was reversible under these conditions. Thus, our results suggest that the gradual onset and long-lasting pharmacologic effect of amlodipine are due to its slow binding kinetics (association and dissociation) of cardiovascular receptor sites in addition to its slow pharmacokinetics.

Amlodipine↗