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S Kitamura

Publications and source records attributed to S Kitamura.

At least 19 recordsLinked to original sources
PubMed1992

Crystal structure of methyl 3-O-beta-D-glucopyranosyl-beta-D-glucopyranoside (methyl beta-D-laminarabioside) monohydrate.

Crystals of methyl 3-O-beta-D-glucopyranosyl-beta-D-glucopyranoside (methyl beta-D-laminarabioside) belong to the orthorhombic system, space group P2(1)2(1)2, with a = 14.548(2), b = 24.252(7), c = 4.938(1) A, and Z = 4. The crystal structure was solved by the direct method and refined by the full-matrix least-squares procedure to an R-value of 0.062 for 1099 observed reflections in the X-ray data. The molecular structure is similar to that of beta-D-laminarabiose. The torsional angles around the glycosidic bonds are influenced by both the existence of an intramolecular hydrogen bond at O-4'... O-5 and the exo-anomeric effect. In the nonreducing residue, the exocyclic O-5-C-5-C-6-O-6 and C-4-C-5-C-6-O-6 torsional angles are (+)gauche and trans, respectively, whereas the corresponding torsional angles in the reducing residue are (-)gauche and (+)gauche. One water molecule cocrystallizes with each disaccharide, and the crystal structure is stabilized mainly by intra- and inter-molecular hydrogen bonds involving water molecules.

Carbohydrate Conformation↗
PubMed1992

New bronchodilators. 3. Imidazo[4,5-c][1,8]naphthyridin-4(5H)-ones.

In order to develop new oral bronchodilators, a series of novel imidazol[4,5-c][1,8]naphthyridin-4(5H)-ones 5 were designed and synthesized. Some of these new heterocycles exhibited more potent bronchodilator activity in vitro and in vivo than theophylline. With respect to modification at the 5-position, both phenyl and n-butyl substitution produced potent activity. Though bulk tolerance at N-3 is observed with short and small lipophilic groups, any substitution at the other positions and transformations of the parent skeleton eliminated activity. Thus 5-phenyl-1H-imidazo[4,5-c][1,8]naphthyridin-4(5H)-one (23) (KF17625), which satisfied these conditions, was selected for further studies (antigen inhalation-induced bronchospasm model; minimum effective dose (MED) = 1 mg/kg, po; antigen-induced contraction of trachea (the Schultz-Dale reaction), IC50 = 2.2 microM). Compound 23 inhibited carbachol-, histamine-, or leukotriene D4-induced contraction and relaxed spontaneous tone in guinea pig isolated tracheal preparations with, 4- to 16-fold greater potency than aminophylline. Thus it appeared to relax directly the airway smooth muscle. 23 did not have any influence on adenosine binding at 10 microM, but inhibited canine tracheal phosphodiesterase (PDE) IV (IC50 = 12 microM) and concanavalin-A-induced histamine release from rat mast cells (44% inhibition at 10 microM). Although the detailed mechanisms of these compounds remain to be elucidated, this series of novel tricyclic heterocycles represents a new class of bronchodilator.

Animals↗
PubMed1992

Contribution of the central interaction between calcium and sodium to hemodynamic regulation in spontaneously hypertensive rats.

The contribution of the central interaction between calcium and sodium to hemodynamic regulation was assessed in spontaneously hypertensive rats (SHRs) and Wistar-Kyoto (WKY) rats. The effect of a high calcium solution (Ca2+, 130 mg/dl, 10 microliters) infused into the cerebral ventricle (i.c.v.) on hemodynamic responses induced by a high sodium solution (Na+, 1,000 mEq/1, 10 microliters) i.c.v. and the mechanism by which high Ca2+ affects the hemodynamic responses induced by high Na+ i.c.v. were studied. High Na+ i.c.v. induced a pressor response with tachycardia in the SHRs, but induced a pressor response with reflex bradycardia in the WKYs. Prior treatment with high Ca2+ i.c.v. attenuated the pressor response induced by high Na+ i.c.v. (+55.6 +/- 4.4 to +33.1 +/- 3.2 mmHg, P < 0.01) and restored reflex bradycardia (+86.4 +/- 7.7 to -26.7 +/- 7.6 bpm, P < 0.01) in SHRs. Whereas prior treatment with high Ca2+ i.c.v. attenuated the pressor response (+35.7 +/- 2.0 to +22.2 +/- 4.0 mmHg, P < 0.05), it did not alter the degree of reflex bradycardia (-81.7 +/- 7.1 to -69.2 +/- 120 bpm, n.s.) in WKYs. Ganglionic blockade attenuated the pressor response (+56.9 +/- 3.5 to +42.9 +/- 2.3 mmHg, P < 0.05) and restored reflex bradycardia (+82.1 +/- 10.3 to -65.9 +/- 11.0 bpm, P < 0.01) in SHRs, whereas, inhibition of arginine vasopressin attenuated the pressor response without modification of the tachycardic response.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

New bronchodilators. 1. 1,5-Substituted 1H-imidazo[4,5-c]quinolin-4(5H)-ones.

A series of novel xanthine-based tricyclic heterocycles in 1H-imidazo[4,5-c]quinolin-4(5H)-ones was designed, synthesized, and tested as potential active bronchodilators. Inhibition of the Schulz-Dale (SD) reaction-induced contraction in trachea and inhibition of antigen inhalation-induced bronchospasm in passively sensitized guinea pigs served as primary in vitro and in vivo assays, respectively. Simultaneous measurement of acute lethal toxicity (minimum lethal dose; MLD, po) in mice allowed determination of a safety margin. The bronchodilatory activity of these heterocycles was considerably varied with the nature of substituents at the 5-position. The most active substituents at the 2- and 5-positions and on the aromatic ring were found to be hydrogen, n-butyl, and hydrogen, respectively. There was a bulk tolerance for lipophilic substituents at the 1-position. 5-Butyl-substituted compounds appeared to be less toxic than theophylline on the basis of MLD data. Thus 5-butyl-1-methyl-1H-imidazo[4,5-c]quinolin-4(5H)-one (10) (IC50 value of the SD assay = 0.25 microM, MLD > 300 mg/kg) was selected for further studies. Compound 10 (KF15570) reduced bronchoconstriction produced by antigen (Konzett-Rössler preparation in anesthetized guinea pigs, ED50 = 0.42 mg/kg, iv) more effectively than aminophylline (ethylenediamine salt of theophylline, ED50 = 7.8 mg/kg, iv) but had fewer side effects on the heart and CNS than theophylline. Compound 10 and its derivatives showed weak adenosine antagonism and phosphodiesterase (PDE) inhibition which could not account for their potent bronchodilation. Although their precise mechanism of action remains unclear, this series of novel tricyclic heterocycles represents a new class of bronchodilator.

Airway Resistance↗
PubMed1992

Differential scanning calorimetric study of the thermal unfolding of mutant forms of phage T4 lysozyme.

In two recent papers, we reported the effects of several point mutations on the thermodynamics of the thermal unfolding of the lysozyme of phage T4 as determined by differential scanning calorimetry. The mutants studied were R96H [Kitamura, S., & Sturtevant, J.M. (1989) Biochemistry 28, 3788-3792] and T157 replaced by A, E, I, L, N, R, and V [Connelly, P., Ghosaini, L., Hu, C.-Q., Kitamura, S., Tanaka, A., & Sturtevant, J.M. (1991) Biochemistry 30, 1887-1891]. Here we report the results of a similar study of the single mutations A82P, A93P, and G113A and the double mutation C54T:C97A. The three single mutants all show small apparent stabilization at pH 2.5 and 46.2 degrees C (the denaturational temperature of the wild-type protein), amounting to -0.5 +/- 0.4 kcal mol-1 in free energy, whereas the double mutant shows a weak apparent destabilization, +0.8 +/- 0.4 kcal mol-1. As in all our previous studies of mutant proteins, the enthalpy changes produced by these mutations are in general of much larger magnitude than the corresponding free energy changes and frequently of opposite sign.

Calorimetry, Differential Scanning↗
PubMed1992

Synthesis of nigero-oligosaccharides.

Nigerose [alpha-D-Glcp-(1----3)-D-Glcp], nigerotriose, nigerotetraose, and nigeropentaose have been synthesized by chain elongation starting at the reducing end, from the corresponding octa-, undeca-, tetradeca-, and heptadeca-beta-D-acetates, respectively, via thioglycoside-mediated 1,2-cis coupling, using 1,2,4,6-tetra-O-acetyl-beta-D-glucopyranose as the glucosyl acceptor and methyl 2,3,4,6-tetra-O-benzyl-1-thio-beta-D-glucopyranoside, methyl 3-O-allyl-2,4,6-tri-O-benzyl-1-thio-beta-D-glucopyranoside, and methyl O-(2,3,4,6-tetra-O-benzyl-alpha-D-glucopyranosyl)-(1----3)-2,4,6-tri-O- benzyl-1-thio-beta-D-glucopyranoside as the donors.

Carbohydrate Sequence↗
PubMed1992

Sex-linked recessive lethal test of Drosophila melanogaster after exposure to 50-Hz magnetic fields.

To determine whether a 50-Hz magnetic field will induce mutations, a sex-linked recessive lethal test of Drosophila melanogaster was performed. Adult flies were exposed at an rms flux density of 500 mu T or 5 mT to the homogeneous field of a Helmholtz coil. The ambient field to which controls were exposed was less than 1 mu T. Exposures took place continuously for 13 to 14 days, which correspond to the life cycle of Drosophila at 25 degrees C. About 10,000 X-chromosomes were tested at each flux density. Recessive lethal mutation rates of 0.13, 0.21, and 0.18 percent were observed, respectively, for control, 500-mu T, and 5-mT conditions. By the Kastenbaum-Bowman significance test, the recessive lethal mutation rates in the 500-mu T and 5-mT conditions did not differ from the mutation rate of controls.

Animals↗
PubMed1992

Internal thoracic artery grafting for congenital coronary malformations.

We report 2 patients with congenital coronary anomalies (atresia of left main coronary artery and anomalous origin of the left coronary artery from the pulmonary artery) successfully treated with single or double internal thoracic artery grafting. Because the internal thoracic artery has a potential for circumferential as well as longitudinal development, and because of the uncertainty of ultimate vein graft function, we believe that the internal thoracic artery is the best graft material for the treatment of congenital coronary malformations requiring bypass operation in children, adolescents, or even in adults.

Child↗
PubMed1992

Angiographic demonstration of no-flow anatomical patency of internal thoracic-coronary artery bypass grafts.

To clarify the no-flow situation of the stringlike internal thoracic artery graft, we angiographically examined such grafts by temporarily occluding the recipient coronary artery with a percutaneous transluminal coronary angioplasty balloon and were able to reveal anatomical patency of the internal thoracic artery graft in 2 patients 1 year and 3 years after the operations. Thus, there is a possibility that internal thoracic artery grafts may continuously maintain anatomical patency even under no-flow situations just like nonfunctioning collateral vessels and may function properly later as a graft when the native coronary flow decreases. Also, this angiographic technique can be a new method for detecting anatomical patency of no-flow and functionally closed internal thoracic artery grafts.

Anastomosis, Surgical↗
PubMed1992

Effects of hormonal supplements on the maintenance of cardiac function in potential donor patients after cerebral death.

It is well-known that cardiac function in cerebrally dead patients rapidly deteriorates, leaving the organ unfit for donation. This study investigated whether or not cardiac function in patients with cerebral death can be maintained in a desirable condition with hormonal supplementation. In studies of changes in hormones before and after cerebral death, insulin, glucagon, triiodothyronine, thyroxine, cortisol, vasopressin, epinephrine, and norepinephrine values were measured with a lapse of time after cerebral death. Among them, triiodothyronine and cortisol levels were markedly reduced after cerebral death; therefore, these two hormones were selected as hormonal supplements. The average period from the judgment of cerebral death to cardiac arrest was 4.3 days in 12 patients with no hormonal supplement (group I) and more than 11.5 days in 4 patients with hormonal supplement (group II). This period for patients in group II was significantly longer (p less than 0.05). In 2 of the group II patients the hormonal supplementation was discontinued at the family's request, and in the other 2 patients, it was discontinued because of proposed renal donation. Hemodynamic comparisons between the two groups showed that the mean arterial pressure and the left ventricular maximum dp/dt were significantly higher (p less than 0.01) as was the cardiac index (p less than 0.05) on the 3rd day after cerebral death in members of group II. Thereafter, in group II, an excellent hemodynamic state was maintained until hormonal supplements were discontinued. We conclude that the triiodothyronine and cortisol supplements were effective in the maintenance of cardiac function in patients after cerebral death.

Adolescent↗
PubMed1992

An HRP study of the location of the motoneurons supplying the tensor veli palatini muscle of the rabbit.

Location of the motoneurons supplying the tensor veli palatini muscle of the rabbit was examined with the retrograde labeling technique following intramuscular injection of HRP. Labeled motoneurons were ipsilaterally located in the ventral or ventromedial portion of the rostral two-thirds of the motor trigeminal nucleus at the level of about 6.0 to 8.5 mm rostral to the obex. The location of the labeled motoneurons was ventromedial to the region supplying the masseter, the temporalis, and the medial pterygoid muscles and ventral to the region supplying the anterior digastric and the mylohyoid muscles, the location which coincided with the lateral pterygoid region. The labeled motoneurons were scattered around or in this region.

Animals↗
PubMed1992

A high-performance liquid chromatographic method for the quantitative enantioselective analysis of mefloquine stereoisomers.

A rapid quantitative, enantioselective HPLC method for the analysis of the four stereoisomers, (+) and (-) erythro and (+) and (-) threo forms, of mefloquine has been developed using a Chiralpak Ad analytical column containing amylose tris-3,5-dimethylphenyl carbonate coated on silica gel and hexane/ethanol/diethylamine (96:4:0.1, v/v%) as the mobile phase. This method made it possible to quantitate small amounts of threo form in the presence of the erythro form of mefloquine, the form which is used as the active ingredient in commercial mefloquine tablets. Tablets from three sources were studied to estimate their optical purity, and it was found that tablets from one source contain 0.27 w/w% of the (-)-threo and 0.25 w/w% of the (+)-threo form, tablets from the second source contain 0.056 and 0.042 w/w% (-)- and (+)-threo, respectively, and tablets from the third source contain 0.052 w/w% (+)-threo, with the remainder erythro.

Chromatography, High Pressure Liquid↗
PubMed1992

Kinetic study of the transformation from tetrahydrate to monohydrate of a new antiallergic, sodium 5-(4-oxo-phenoxy-4H-quinolizine-3-carboxamide)-tetrazolate.

Two hydrates (tetrahydrate, I, and monohydrate, II) of a new antiallergic, sodium 5-(4-oxo-phenoxy-4H-quinolizine-3-carboxamide)-tetrazolate (FR71021), were prepared and characterized by means of infrared spectrometry, thermal analysis, and power X-ray diffraction spectrometry. While I was confirmed to dehydrate readily resulting in an anhydrate form (noncrystalline form) below its critical relative humidity for dehydration, I was also transformed into II under humid conditions. The transformation kinetics from I to II were investigated under varying temperature and humidity conditions by a powder X-ray diffraction technique. The transformation mechanism followed a zero-order reaction, and the apparent transformation rate constant (k) could be described as a function of water vapor pressure (P), temperature (T), and the interaction orders between water vapor pressure and the samples (s): k = A.exp(-Ea/RT).Ps, where Ea is the activation energy and R is the gas constant.

Biotransformation↗
PubMed1992

Incidence of Paneth cells in minute tubular adenomas and adenocarcinomas of the large bowel.

This study attempted to demonstrate the incidence of Paneth cells within large bowel tubular adenoma and adenocarcinoma according to location and macroscopic appearance using minute tumors (up to 5 mm in size). We have shown that Paneth cells were sometimes seen in the early stage of the development of large bowel epithelial neoplasia. According to the macroscopic appearance (elevated or depressed type), in large bowel epithelial neoplasia, there was a statistical difference between the depressed type (32.5%, 14 of 40 cases) and the elevated type (16.6%, 24 of 145 cases) (Chi square analysis, p < 0.05) in the incidence of Paneth cells. Paneth cells were seen more frequently in adenocarcinoma (45.8%, 11 of 24 cases) than in tubular adenoma (16.8%, 27 of 161 cases), with a significant statistical difference (Chi square analysis, p < 0.01). According to location, in both tubular adenoma and adenocarcinoma, Paneth cells were more frequently observed in the proximal colon (tubular adenoma: p < 0.01, adenocarcinoma: p < 0.05, Chi square analysis).

Adenocarcinoma↗
PubMed1992

New bronchodilators. II. 3H-imidazo[4,5-c]quinolin-4(5H)-ones.

A series of novel 3-substituted imidazo[4,5-c]quinolin-4(5H)-ones (2a-w) was prepared by the reaction of imidazo[4,5-c]quinolin-4(5H)-ones (6) with several electrophiles under basic conditions. The bronchodilatory activity of these compounds was evaluated on the basis of their protective effects against antigen-induced contraction (the Schultz-Dale reaction) of guinea-pig trachea (in vitro) and antigen inhalation-induced bronchospasm in passively sensitized guinea-pigs (in vivo). Although correlations between in vitro and in vivo activities were not clear, short alkyl chains such as the methyl and ethyl groups at the 3-position were important for potent activity, especially in vivo. Substituents at the 5-position were more tolerant of the activity than those at the 3-position. 5-Ethyl-3-methyl-3H-imidazo[4,5-c]quinolin-4(5H)-one (21) exhibits the most potent bronchodilatory activity among our tested compounds and is at least 5-fold more active than theophylline in vivo.

Animals↗
PubMed1992

Ultrasonographic evaluation of neck and supraclavicular lymph nodes metastasized from lung cancer.

The significance of ultrasonography in the evaluation of metastasized neck and supraclavicular lymph nodes from lung cancer was analyzed. By ultrasonography, the lymph nodes could be visualized clearly as low-echogenic round areas, and the size could be precisely measured in three dimensions. It was also possible to diagnose whether or not the lymph node adhered to the surrounding tissues and to determine the relationship and the connection of supraclavicular lymph node and upper mediastinal lymph node. The therapeutic effect related to the size of the lymph node was evaluable by ultrasonography. Therefore, the ultrasonographic approach to the neck and supraclavicular lymph nodes metastasized from lung cancer is considered to be useful for clinical use.

Clavicle↗