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Biomedical subjects

Y Hirota

Publications and source records attributed to Y Hirota.

At least 19 recordsLinked to original sources
PubMed1992

Noninvasive detection of left ventricular diastolic dysfunction using M-mode echocardiography to assess left ventricular posterior wall kinetics in hypertrophic cardiomyopathy.

In patients with hypertrophic cardiomyopathy (HC), it is difficult to determine the severity of left ventricular (LV) diastolic dysfunction. Three different patterns of LV posterior wall motion were found by M-mode echocardiography in patients with HC, and the use of these patterns is proposed as a new noninvasive index of the severity of LV diastolic dysfunction. M-mode echocardiograms were recorded prospectively from 35 patients with HC, and the posterior wall motion pattern in late systole and early diastole was classified into the following 3 types: (1) normal motion (n = 9); (2) flat motion--flat motion from late systole to early diastole, followed by rapid backward movement (n = 13); and (3) downward motion--slow backward movement from late systole (n = 13). There were no differences in the severity or type of hypertrophy, LV systolic function and pulsed Doppler indexes of LV filling among these 3 groups. However, LV end-diastolic pressure was increased in the groups with flat (15 +/- 6 mm Hg) and downward (16 +/- 9 mm Hg) motion. Furthermore, the maximal rate of decrease in LV pressure (normal 1,450 +/- 300, flat 1,250 +/- 300 and downward 860 +/- 80 mm Hg/s) and the time constant of LV pressure reduction (normal 60 +/- 15, flat 70 +/- 25 and downward 101 +/- 34 ms) showed a stepwise deterioration from the normal to the flat and then to the downward motion groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Angiotensin II↗
PubMed1992

Structures of grain boundaries in long-chain Te crystals observed by high-resolution transmission electron microscopy.

Vacuum-deposited Te crystals, composed of endless chains of the right-handed or left-handed spiral, have been investigated by high-resolution electron microscopy with the aid of image simulation. A (010) grain boundary, which accompanies edge dislocations having an extra layer of the width of one Te chain, has been observed. A through-focal series of images reveal that it is not a reflectional nor a rotational twin boundary but a small angle grain boundary in a single crystal or an inversion twin. The lattice on one side of the boundary is shifted from that on the other side by [001]c/3 + [120]a/8, and inclined at 1.1 degrees around the c-axis of the other side. Also found between crystallites of [100] and [011] orientation is a grain boundary which is built with the (011) facets on one side of the boundary and the (211) or (0,1,10) facets on another side.

Crystallization↗
PubMed1992

Alteration of the curved helical structure located in the upstream region of the beta-lactamase promoter of plasmid pUC19 and its effect on transcription.

The region preceding the beta-lactamase promoter of Escherichia coli plasmid pUC19 has a curved DNA (bent DNA) structure. The center of the curvature was revealed to exist around nucleotide position 2580 of the plasmid, which is just beside RNA polymerase binding region. It was indicated that the identified region is curved even at 60 degrees C. The gross geometry of the curvature was altered by inserting synthetic double-stranded oligonucleotides between positions 2585 and 2586. Effect of the alteration on strength of the promoter was not detected in vitro. However, in vivo analyses showed that the promoter strength is apparently dependent, in part, on the gross geometry of the curvature. Insertions of 4 and 16 bp, both of which altered the gross geometry of the curvature greatly, caused considerable reductions of in vivo level of beta-lactamase mRNA. In vivo, overall three-dimensional structure of the region covering the promoter and the curvature seems to play some significant role in transcription of the gene.

Base Sequence↗
PubMed1992

Differentiation profiles of normal blast cell colonies derived from mononucleated cells, T cell depleted nonadherent cells and CD33-negative, CD34-positive normal human bone marrow cells.

Blast cell colonies can be grown reproducibly in methylcellulose from normal human mononuclear bone marrow cells (MNC) in the presence of 30% human plasma, 1 U human recombinant erythropoietin and 10% of medium conditioned by phytohemagglutinin stimulated leukocytes as a source of growth factors. The colonies can be recognized by inverted microscopy by their display of highly refractile cytoplasmic structures that resemble small vacuoles. A proportion of cells within these colonies remains CD34-positive (CD34+). The blast-like morphology of these cells was sustained for at least 14 to 21 days. The frequency of blast cell colony forming units (CFU-BL) can be increased by a series of separation procedures to produce E-rosette depleted, nonadherent cells (E-NAC), CD34+ cells and CD33-CD34+ cells. The mean number of CFU-BL per 10(5) cells was 1.9 +/- 1.6 in MNC, 5.7 +/- 2.7 in E-NAC, 108 +/- 51 in CD34+ cells and 112 +/- 109 in CD33-CD34+ cells. The enrichment procedures were not specific for CFU-BL but also resulted in a similar increase of multilineage and single lineage progenitors. The relative proportions of CFU-BL and other progenitors remained unchanged among these subpopulations. The size of individual blast cell colonies on day 16 varied from 20 to 1,600 cells. After 14 to 21 days, cells within blast cell colonies acquired mature morphological features. The majority of blast cell colonies developed into multilineage colonies (62%); some (38%) were restricted to a single hemopoietic lineage. Larger blast cell colonies had a higher probability of developing into multilineage colonies than smaller blast cell colonies.

Antigens, CD↗
PubMed1992

Various factors associated with the manifestation of influenza-like illness.

A survey enrolling 814 schoolchildren was conducted immediately after a peak epidemic in the 1988-1989 influenza season and then a case-control study for influenza-like illness (ILI) was carried out using information concerning illness onset and usual lifestyle. Based on the analysis of the correlations among symptoms and actions taken due to symptoms, cases were defined as those with fever greater than or equal to 38 degrees C and subsequent absenteeism and medical consultation during peak epidemic; within this, mild-ILI (MILI) was defined as fever greater than or equal to 38 degrees C and less than 39 degrees C, and severe-ILI (SILI) as fever greater than or equal to 39 degrees C. Controls were defined as those with no symptoms (NS) during that period. Adjusted odds ratios (OR) were obtained through an unconditional logistic regression model between the MILI (80) or SILI (48) and NS (196) groups from among respondents (803). For MILI, increased risks were observed for easily-inflamed tonsils (OR = 3.0, 95% CI: 1.7-5.4); and larger family size (1.9, 1.1-3.4); with decreased risks for higher school grades (0.4, 0.2-0.9); frequent intake of vegetables or fruits other than green/yellow vegetables (0.5, 0.3-1.0); and larger room space per capita (0.4, 0.2-0.9). For SILI, there were increased risks for easily-inflamed tonsils (3.8, 1.8-8.1) and history of doctor-diagnosed asthma (2.9, 1.2-6.7); and decreased risks for higher grades (0.2, 0.1-0.6), frequent intake of milk or dairy products (0.3, 0.1-0.6) and vaccination (0.3, 0.1-0.8).

Case-Control Studies↗
PubMed1992

Imbalance of deoxyribonucleoside triphosphates and DNA double-strand breaks in mouse mammary tumor FM3A cells treated in vitro with an antineoplastic tropolone derivative.

The mechanism by which alpha,alpha-bis(2-hydroxy-6-isopropyltropon-3-yl)-4-methoxytolu ene (JCI-3661) kills mouse mammary tumor FM3A (F28-7) cells was studied. When the cells were exposed to the drug at 3.7 microM, the intracellular dNTP pool became imbalanced because of decreases in dGTP and dATP and an increase in dTTP. The pattern of the dNTP imbalance was the same as that caused by hydroxyurea. When JCI-3661 was added to the culture medium, mature DNA strands broke, giving fragments of 100-200 kilobase pairs long as found by orthogonal-field-alternation gel electrophoresis. DNA strand breaks, detected by this technique, were observed in the cells at 12 h after the addition. The beginning of cell death was observed at about 14 h (trypan blue staining) or at about 12 h (colony-forming ability) after cultivation Breaks in the single and double strands of DNA, as measured by alkaline and neutral filter elution assay, became evident 24 h after treatment with 3.7 microM JCI-3661. Comparison of the ratio of single- and double-strand breaks caused by JCI-3661 to that following radiation suggested that JCI-3661 broke only double strands. Cycloheximide inhibited both the breakage of double strands and the cell death caused by JCI-3661. JCI-3661 decreased DNA synthesis more than RNA or protein synthesis. The breaks in double strands of DNA were probably important in the cell death caused by JCI-3661.

Animals↗
PubMed1992

Clinical significance of normal cardiac silhouette in dilated cardiomyopathy--evaluation based upon echocardiography and magnetic resonance imaging.

It is generally believed that patients with dilated cardiomyopathy have a large cardiac silhouette on chest roentgenography. Contrary to this general belief, we have recently examined several patients with a dilated left ventricle (LV) on echocardiography but in whom the cardiothoracic ratio (CTR) was within normal limits. To investigate this apparent discrepancy, we evaluated the relationship between LV dimensions, measured on M-mode echocardiography, and CTR in 49 patients with dilated cardiomyopathy. Among these patients, 11 (22%) had a CTR less than 50% and 38 (78%) had a CTR greater than 50%. The spatial orientation (cardiac rotation) of the LV within the thorax was evaluated by magnetic resonance imaging (MRI) in 5 patients with a CTR less than 50% and in 7 patients with a CTR greater than 50%, in comparison with 7 normal controls. In each of these patients, cardiac rotation was assessed from both a transverse and a frontal MRI section. In both groups, LV end-diastolic dimension was greater than 5 cm. Transverse cardiac rotation was 32 +/- 8 degrees in patients with a CTR less than 50%. This was significantly lower than in the 7 normal controls (43 +/- 7 degrees) (p less than 0.05). In patients with a CTR greater than 50%, however, transverse cardiac rotation (55 +/- 5 degrees) was significantly greater than in normal controls (p less than 0.01). No differences in frontal cardiac rotation was observed between the 2 groups. These data indicate that a normal cardiac silhouette in patients with dilated cardiomyopathy can be explained on the basis of a counterclockwise transverse rotation of the heart within the thorax, and it cannot always rule out the dilatation of the LV.

Adolescent↗
PubMed1992

Individual and environmental characteristics related to influenza-like illness among children: a school-based case-control study.

To investigate individual and environmental characteristics associated with the manifestation of influenza-like illness (ILI), a survey enrolling 509 schoolchildren was conducted after an epidemic peak in the 1988/89 season, and then a case-control study was designed according to the information concerning illness onset and usual life-style. Case series were defined as those with fever greater than or equal to 38 degrees C due to acute respiratory illness, subsequent absenteeism and medical consultation during the epidemic peak; mild-ILI (MILI; fever greater than or equal to 38 degrees C and less than 39 degrees C) and severe-ILI (SILI; fever greater than or equal to 39 degrees C). Control series were defined as those with no symptoms (NS) during the same period. An adjusted odds ratio (OR) was obtained using an unconditional logistic regression model for MILI (55) or SILI (33) and NS (204) groups among respondents (508). For MILI, increased risk was observed for easily inflamed tonsils (OR, 3.2; 95% CI, 1.6-6.4), with decreased risks for higher school grade (0.4, 0.2-0.8) and frequent intake of milk or dairy products (0.5, 0.3-1.0), but no significant association was determined for vaccination (0.6, 0.3-1.2). For SILI, there was an increased risk for easily inflamed tonsils (3.3, 1.4-7.9); and decreased risks for the higher grades (0.1, 0.1-0.3); use of a kerosene or gas heater with indoor exhaust (0.4, 0.2-0.9); and vaccination (0.3, 0.1-0.7). The OR of vaccinees for SILI constantly decreased regardless of grade and easily inflamed tonsils.

Age Factors↗
PubMed1992

Changes in the level of plasma cortisol, progesterone and total testosterone in developing hairless dogs.

Changes in the levels of plasma cortisol, progesterone and total testosterone were examined in developing hairless and haired dogs. Cortisol levels in the hairless dogs seemed to be higher than those in haired dogs within the age of 4-5 weeks. No apparent changes were seen in the level of plasma progesterone between the groups of hairless females and haired females. Total testosterone levels in hairless males showed to be significantly lower than those in haired males at the age of 13-21 weeks.

Animals↗
PubMed1992

Conglutinin, mannan-binding protein, and serum amyloid P component concentrations in sera from cows: changes associated with mastitis.

To study the roles of conglutinin (Kg), mannan-binding protein (MBP), and serum amyloid P component (SAP) in the protection of cattle against infections, the concentrations of these proteins in the sera from cows with mastitis were determined by sandwich enzyme-linked immunosorbent assays. The Kg and MBP concentrations in the sera from cows with mastitis were much lower than those from uninfected (or clinically healthy) ones, and increased after recovery. No significant difference in the SAP concentrations was found between healthy and infected cows. With the sera from cows experimentally infected with bovine leukemia virus, the Kg concentrations were also lower than those from uninfected ones, whereas the MBP concentrations were not. From these findings, the Kg concentration is suggested to be serologically a possible indicator for clinical diagnosis of treatment for mastitis although both Kg and MBP concentrations were found to decrease in cows with mastitis and to increase after recovery.

Animals↗
PubMed1992

Synthesis and property of alpha-oligodeoxynucleotide phosphorothioate.

Unnatural DNA analog, alpha-2'-deoxy-oligoadenylate phosphorothioate bearing 3'-normal monophosphate moiety was conveniently synthesized through phosphoramidite solid support method. The starting material of the DNA analog, alpha-2'-deoxyadenosine, was prepared in a stereospecific manner by the coupling reaction between activated nucleobase and 1-chloro-2-deoxyribose derivative.

Adenine Nucleotides↗
PubMed1992

DNA conformation of the region preceding the beta-lactamase promoter of pUC19 which is required for efficient transcription.

The upstream region of the beta-lactamase promoter of Escherichia coli plasmid pUC19 has a DNA curvature (bent DNA). This region was replaced with another sequence by using randomly synthesized oligonucleotides. Among the reconstructed plasmids, a plasmid which could endow E. coli cells with the strongest resistance to ampicillin on plates was selected. Nucleotide sequence and DNA conformation of the altered region was investigated.

Base Sequence↗
PubMed1992

Prominent negative T waves with QT prolongation indicate reperfusion injury and myocardial stunning.

To observe the clinical course after reperfusion and recovery from myocardial stunning of the left ventricular anterior wall, we prospectively reviewed and analyzed cardiac enzymes, ECG changes, echocardiograms, and cineangiograms in 8 patients with the acute ischemic syndrome who fulfilled the following criteria: 1) no history of previous myocardial infarction, 2) repeated and/or prolonged episodes of chest pain, 3) critical stenosis of the left anterior descending artery with wall motion abnormalities, 4) successful emergency percutaneous transluminal coronary angioplasty, and 5) normal wall motion on repeat cineangiography 4 to 8 weeks later. Creatine kinase (CK) and/or its cardiac isoenzyme (CK-MB) were minimally elevated in all cases. Wall motion was normalized with the reduction of end-systolic volume (end-diastolic volume: from 139 +/- 25 to 140 +/- 37 ml, ns, end-systolic volume: from 68 +/- 16 to 39 +/- 13 ml, p < 0.001, ejection fraction: from 51 +/- 6 to 71 +/- 6%, p < 0.001). Serial echocardiograms showed normalization of wall motion within 4 to 28 days. T wave inversion in the left precordial leads developed 30 min to 5 hours after the cessation of chest pain or successful reperfusion, and prominent negative T waves (1.6 +/- 0.6 mV) with QT prolongation (0.56 +/- 0.08 sec) in V3 or V4 reached their peak values within one to 5 days. ECG abnormalities resolved after 21 to 95 days. These ECG findings may indicate reperfusion injury and the presence of myocardial stunning in the anterior wall of the left ventricle.

Aged↗
PubMed1992

[Radionuclide therapy of Sipple syndrome using iodine-131 metaiodobenzylguanidine].

A 40-year-old female who had lung and liver metastases from malignant pheochromocytoma was treated with 3.7 GBq 131I-MIBG (metaiodobenzylguanidine). After the treatment, 131I-MIBG showed increased uptake in the metastatic lesions of the lung and liver. The size of tumor was no significant change on CT and MRI, but the intensity of liver metastases decreased gradually on MRI. Prior to the treatment, the levels of adrenaline and noradrenaline were high. One to three days after treatment, the level of these laboratory data further increased, but they gradually decreased in 1 to 3 months. These changes may be due to necrosis of tumor tissue.

3-Iodobenzylguanidine↗
PubMed1992

Displacement of the endotracheal tube caused by postural change: evaluation by fiberoptic observation.

Unexpected displacement of the endotracheal tube during anesthesia caused by postural change of the neck or passive compression by the mouth gag was investigated under transluminal fiberoptic observation. Twenty-two patients were divided into orotracheal and nasotracheal intubation groups according to the technical requirements of the planned oral and maxillofacial surgery. Under nasotracheal intubation, the mean length of displacement from the carina was 21 mm by extension of the neck, and 8 and 7 mm by lateral rotation of the neck to the right and left sides, respectively. Under orotracheal intubation, the mean length of displacement from the carina was 12 mm by extension of the neck and almost 28 mm with application of the mouth gag. To avoid accidental extubation or one-sided bronchial intubation during anesthesia, the tip (distal end) of the endotracheal tube should be located less than 32 mm from the carina before extension of the neck and more than 41 mm from the carina before application of the mouth gag.

Adolescent↗
PubMed1992

Effects of epinephrine and norepinephrine contained in 2% lidocaine on hemodynamics of the carotid and cerebral circulation in older and younger adults.

The effects of vasoconstrictor-containing local anesthetics on the carotid and cerebral circulation were investigated using an ultrasonic quantitative blood flow measurement system. Nineteen healthy adult volunteers were divided into two groups according to age. The local anesthetics used were 2% lidocaine containing 1:80,000 epinephrine and 2% lidocaine containing 1:25,000 norepinephrine. One (1.8 mL) or two (3.6 mL) cartridges of each anesthetic were injected into unilateral or bilateral maxillary gingivae. Epinephrine-containing lidocaine had little effect on carotid and cerebral hemodynamics. Norepinephrine-containing lidocaine increased arterial blood pressure, decreased heart rate, and decreased carotid arterial blood flow and velocity, which caused increased cerebrovascular resistance and decreased cerebrovascular capacitance. The results suggest that norepinephrine may induce vasoconstriction of the cerebral blood vessels in both young and old adults in a dose-dependent manner. These changes appear to be greater in older people.

Adult↗
PubMed1992

Development of enzyme-linked immunosorbent assays for conglutinin, mannan-binding protein, and serum amyloid-P component in bovine sera.

Sandwich ELISA were developed to quantitatively determine conglutinin (CG), mannan-binding protein (MBP), and serum amyloid-P component (SAP) in the sera of cattle. The ELISA system was found to have high repeatability for quantitation of these serum proteins at concentration as low as 5 ng/ml. From results obtained for 10 healthy cows aged 2 to 7 years, mean +/- SD serum concentrations were 56.5 +/- 14.4 micrograms of CG/ml, 2.37 +/- 0.87 micrograms of MBP/ml, and 11.14 +/- 3.92 micrograms of SAP/ml, respectively. Values in 6 healthy heifer calves aged 6 months were 3.45 +/- 1.22 micrograms/ml for CG, 1.71 +/- 0.96 micrograms/ml for MBP, and 5.45 +/- 2.75 micrograms/ml for SAP, respectively. Concentrations in 9 healthy bullocks aged 6 months were 1.83 +/- 0.66 micrograms/ml for CG, 1.04 +/- 0.63 micrograms/ml for MBP, and 4.9 +/- 1.13 micrograms/ml for SAP, respectively.

Animals↗