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S Kitamura

Publications and source records attributed to S Kitamura.

At least 523 records · Page 29Linked to original sources
PubMed1994

[Allograft (homograft) valve surgery: current status in Japan].

The advance of cryopreservation techniques has dramatically increased the durability of human allograft valves, resulting in the wide-spread use of allograft valves in many western countries except Japan. The superiority of the allograft valve to other prosthetic valves has become apparent in some specific situations such as active endocarditis, small aortic root and hemorrhagic conditions. In this manuscript, we described the setting-up of the cryopreservation laboratory, quality control and the clinical use of allograft valves in our institute. The authors believe that surgeons should have an option of utilizing allograft valves in selected patients in Japan.

Adult↗
PubMed1994

[Coronary artery bypass surgery-redo operation particularly in patients with a functioning ITA graft or with a patent atheromatous vein graft].

An experience with redo-CABG in 20 patients is described. The incidence of reoperation in patients undergoing primary CABG in our hospital was 1.4%, relatively low even in Japanese population. The low incidence of redo-CABG in our hospital depends on the relatively short period of follow-up of 14 years, the prevalence of interventional cardiology and the early routine use of ITA grafts. The main cause of reoperation was the failure of a SVG to the LAD in 70 to 80% of the cases. The most important and difficult decision-making in redo-CABG is the selection of surgical approaches and cardioprotective methods in patients with a patent functioning ITA graft, and the management of an atherosclerotic patent SVG. Surgical strategies in these situations are discussed.

Adult↗
PubMed1993

Depressor effect of intraventricular administration of calcium on spontaneously hypertensive rats.

The role of central Ca2+ in the regulation of blood pressure (BP) was investigated in conscious spontaneously hypertensive (SHR) and Wistar-Kyoto rats (WKY). Ten microliters of a high Ca2+ solution (Ca2+: 32.6 mM) administered intracerebroventricularly (i.c.v.) decreased the mean arterial pressure (MAP) for more than 20 min in SHR (n = 7, P < 0.005), while no change of MAP was observed in the WKY (n = 6). This depressor response to Ca2+ i.c.v. was dose-dependent at Ca2+ concentrations between 16.3 and 65.2 mM. We also investigated the effect of high Ca2+ i.c.v. in SHR after pretreatment with Ca2+ channel blockers, diltiazem (60 micrograms/10 microliters) or nisoldipine (4, 8, 16 and 32 micrograms/10 microliters), administered i.c.v., the autonomic ganglion blocker, hexamethonium (50 mg/kg), administered i.v. and alpha-methyl-p-tyrosine (100 and 400 micrograms/10 microliters) delivered i.c.v. Pretreatment with i.c.v. diltiazem (n = 8) or nisoldipine (n = 5 for 8 micrograms, n = 6 for 4, 16, 32 micrograms) abolished and/or blunted the decrease of MAP due to high Ca2+. Hexamethonium administered i.v. (n = 6) also canceled the depressor action of i.c.v. Ca2+. Pretreatment with 100 micrograms of i.c.v. alpha-methyl-p-tyrosine could not prevent the depressor action of i.c.v. Ca2+; however, 400 micrograms of alpha-methyl-p-tyrosine administered i.c.v. abolished the effect of i.c.v. Ca2+. Furthermore Ca2+ channel blockers administered i.c.v. in themselves increased MAP in SHR (P < 0.05). These results suggest that central Ca2+ is involved in the central regulation of BP in SHR. This effect may be mediated through changes in sympathetic activity.

Animals↗
PubMed1993

Synthesis of the laminara-oligosaccharide methyl beta-glycosides of dp 3-8.

Ethyl 2,3,4,6-tetra-O-acetyl-1-thio-alpha-D-glucopyranoside has been prepared in a good yield by anomerization of the corresponding beta-thioglucoside with tin(IV) chloride and transformed, in three steps, into ethyl 2-O-benzoyl-4,6-O-benzylidene-1-thio-alpha-D-glucopyranoside (18). Chloroacetylation of 18, followed by treatment of the product with chlorine gave crystalline 2-O-benzoyl-4,6-O-benzylidene-3-O-chloroacetyl-beta-D-glucopyranosyl chloride (20). This was coupled with methanol in the presence of silver carbonate-silver perchlorate and the product was O-dechloroacetylated to afford methyl 2-O-benzoyl-4,6-O-benzylidene-beta-D-glucopyranoside (22). Silver triflate-promoted glucosylation of 18 with 20 gave a beta-(1-->3)-linked disaccharide derivative, reaction of which with chlorine yielded crystalline O-(2-O-benzoyl-4,6-O-benzylidene-3-O-chloroacetyl-beta-D-glucopyranosyl) - (1-->3)-2-O-benzoyl-4,6-O-benzylidene-beta-D-glucopyranosyl chloride (24). Likewise, condensation of 22 with 20 gave a beta-(1-->3)-linked disaccharide glycoside, which was partially deprotected to give methyl O-(2-O-benzoyl-4,6-O-benzylidene-beta-D-glucopyranosyl)-(1-->3)-2-O-benz oyl- 4,6-O-benzylidene-beta-D-glucopyranoside (26). The methyl beta-glycosides of a homologous series of (1-->3)-linked beta-D-gluco-oligosaccharides from the tri- to the octa-saccharide have been synthesized in a blockwise manner by using 22 and 26 as the glycosyl acceptors, 24 as the disaccharide donor, and silver triflate as the promoter.

Carbohydrate Conformation↗
PubMed1993

Transbronchial lung biopsy in the diagnosis of suspected ocular sarcoidosis.

We conducted clinical research using transbronchial lung biopsy in 60 patients with suspected ocular sarcoidosis who showed no bilateral hilar lymphadenopathy and sparse contributory evidence for sarcoidosis. The patients had a combination of granulomatous iritis with mutton-fat keratic precipitates or iris nodules, trabecular nodules, tent-like peripheral anterior synechiae, snowball or string-of-pearls vitreous opacities, retinal perivasculitis, and spotty retinochoroidal exudates. The transbronchial lung biopsy specimen showed noncaseating epithelioid granuloma in 37 patients (61.7%); these patients were diagnosed as having sarcoidosis. Bronchoalveolar lavage showed a high percentage of patients with an increased lymphocyte fraction among those with positive transbronchial lung biopsy results. The present results may serve as a basis for a clinical diagnosis of sarcoidosis in patients with suspected sarcoidosis without apparent extraocular manifestations.

Adolescent↗
PubMed1993

Nucleus ambiguus of the rabbit: cytoarchitectural subdivision and myotopical and neurotopic representations.

The cytoarchitectural subdivisions of the nucleus ambiguus of the rabbit and its myotopical and neurotopical representations were investigated with HRP labeling. The nucleus was subdivided into the compact cell group (CoG), the medial and lateral scattered cell groups (SGm and SGl), and the diffuse cell group (DiG). The CoG was formed by esophageal, pharyngeal constrictor, and palatal motoneurons in the rostral half of the nucleus. The SGm and SGl were located medial and lateral to the CoG, respectively, in the rostral one-third of the nucleus. Stylopharyngeal and cricothyroid motoneurons were located in the most rostral one-fifth of the SGm and the remaining four-fifths, respectively, whereas the SGl was not labeled with HRP injections into the palatal, pharyngeal, esophageal, and laryngeal muscles. The DiG was formed by recurrent laryngeal motoneurons in the caudal two-thirds of the nucleus. Neurons of origin for the glossopharyngeal nerve occupied the stylopharyngeal region, with a few of them scattered in the CoG and SGl. Neurons giving rise to axons in the superior laryngeal nerve occupied the cricothyroid region, with a few of them scattered in the pharyngeal constrictor region; whereas the pharyngeal vagal branch originated from the pharyngeal constrictor and palatal regions. Neurons of the DiG, SGl, and esophageal region contributed to the infranodosal vagus nerve; esophageal fibers of the recurrent laryngeal nerve originated from the dorsal esophageal region. Laryngeal fibers of the recurrent laryngeal nerve originated from the DiG, the caudal neurons of which had axons traversing the cranial accessory root.

Accessory Nerve↗
PubMed1993

Temperature-induced conformational transition in xanthans with partially hydrolyzed side chains.

The conformational properties of xanthans with partially hydrolyzed side chains were investigated by optical rotation, CD, and differential scanning calorimetry (DSC). All variants displayed the well-known temperature-driven, cooperative order-disorder transition, and both optical rotation and DSC showed that the transition temperature was essentially independent of the content of terminal beta-mannose. It was found that up to 80% of the changes in the specific optical rotation accompanying the transition reflects conformational changes linked to the terminal beta-mannose in the side chains. Modification of the side chains also affected the CD when xanthan was in the ordered state, but in this case the data suggest that the glucuronic acid is the major component determining the magnitude of the CD signal. DSC measurements showed that the transition enthalpy (delta Hcal) increased linearly with the fraction of beta-mannose, again indicating that a significant part (up to 80%) of delta Hcal reflects conformational changes in the side chains. The conformational transition of the xanthan variants generally showed a higher degree of cooperativity (sharper transition) than unmodified, pyruvated xanthan. Calculation of the cooperativity parameter sigma by means of the Zimm-Bragg theory (OR data) or from the ratio between delta Hcal and the van't Hoff enthalpy (delta HvH) using DSC data showed a correlation between sigma and the content of beta-mannose, but the two methods gave different results when the content of beta-mannose approached 100%. The ionic strength dependence of the transition temperature, expressed as d (log I)/d(T-1m), was nearly identical for intact xanthan and a sample containing only 6% of the terminal beta-mannose. Application of the Manning polyelectrolyte theory does not readily account for the observed delta Hcal values, neither does it provide new information on the nature of the ordered and disordered conformations in xanthan.

Calorimetry, Differential Scanning↗
PubMed1993

Physicochemical properties of (1-->6)-branched (1-->3)-beta-D-glucans. 1. Physical dimensions estimated from hydrodynamic and electron microscopic data.

The physical dimensions of several (1-->6) branched (1-->3)-beta-D-glucan samples obtained from different organisms and their derivatives have been studied by electron microscopy, light scattering measurements, viscometry, and gel permeation chromatography. The electron micrographs indicate that in most samples these biopolymers are adequately described as linear worm-like coils. A sample reconstituted from alkaline media appeared as a blend of the linear, circular, and aggregated polymer morphologies. The average mass per unit length, ML = Mw/Lw for the macroscopically linear samples, was estimated to be 2100 +/- 200 g mol-1 nm-1. The parameter ML was determined from the contour lengths obtained by electron microscopy and the molecular weight by light scattering measurements. The observed ML was consistent with the triple-helical structure reported from x-ray diffraction studies and observed degree of side-chain substitution. From the molecular snapshots shown in the electron micrographs, the persistence lengths of these beta-D-glucans were determined to be 140 +/- 30 nm. The experimentally determined intrinsic viscosities were consistent with these estimates of ML and persistence length. Comparison of the molecular weight distributions obtained from gel permeation chromatography and those deduced from the electron micrographs indicates that number and weight average contour lengths are more reliable than z and z + 1 averages.

Carbohydrate Conformation↗
PubMed1993

Purification and characterization of salicylhydroxamic acid reductase from rat liver.

Salicylhydroxamic acid reductase, which catalyzes the reduction of salicylhydroxamic acid to salicylamide, was purified from rat liver cytosol. The purification procedure consisted of fractionation with ammonium sulfate, chromatography with Phenyl-Toyopearl 650, DEAE-cellulose, hydroxyapatite, and Sephadex G-200, and chromatofocusing with PBE94. The molecular weight of the enzyme was estimated to be about 140,000 by Sephadex G-200 gel filtration and 152,000 by polyacrylamide gel electrophoresis. The enzyme was dissociated into two different subunits with estimated molecular weights of 41,000 and 32,000, respectively, by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. These facts suggested that the enzyme is a heterotetramer consisting of two pairs of two nonidentical polypeptide chains. The Km value of the enzyme for salicylhydroxamic acid was estimated to be 91.5 or 88.7 microM in the presence of NADH or NADPH, respectively. The isoelectric point of the enzyme is pH 5.4. The enzyme was highly specific for salicylhydroxamic acid, but it also showed some activity with other hydroxamic acids such as nicotinohydroxamic acid and N-hydroxy-2-acetylaminofluorene. The enzyme activity was inhibited by allopurinol, oxipurinol, dicumarol, menadione, p-chloromercuribenzoic acid, sodium arsenite, potassium cyanide, cupric sulfate, and disulfiram, but little inhibition was observed with oxygen.

Animals↗
PubMed1993

Giant benign mesenchymoma of the mediastinum causing superior vena cava syndrome: report of a case.

The surgical resection of a giant primary mediastinal mesenchymoma causing superior vena cava syndrome is herein described. A 53-year-old man was admitted to the hospital complaining of severe dyspnea. A chest roentgenogram showed a large mediastinal mass shadow compressing the superior vena cava. At surgery, a yellow tumor measuring 27 x 25 x 12 cm and weighing 3,620 g was resected. The histological diagnosis was benign mesenchymoma. The patient's postoperative course was uneventful with a successful resolution of his superior vena cava syndrome.

Humans↗
PubMed1993

A pathohistological and biochemical study of arteriosclerosis in the internal thoracic artery, a vessel commonly used as a graft in coronary artery bypass surgery.

Pathohistological and biochemical studies were conducted on the severity of arteriosclerosis in the internal thoracic artery (ITA), an artery commonly used for coronary artery bypass grafting (CABG). For the pathohistological examination, 26 bilateral ITAs and 13 left anterior descending coronary arteries (LADs) obtained in full length from 13 autopsy cases, none of which had died of arteriosclerotic heart disease, were used. The ratio of the thickness of the intima to that of the media (R) was used as the index for arteriosclerosis. ITAs and LADs were classified as grades I to IV according to the value of R. The R of the ITAs was approximately 1/10 that of the LADs (P < 0.01). Most ITAs showed a low arteriosclerotic grade, with no variation in arteriosclerosis along their length and a low R in all segments. No difference was found between right and left ITAs. Biochemical examination was conducted on 12 ITAs and 11 LADs, obtained from 12 different and unselected autopsy cases. The lipid content in the vascular wall was determined to evaluate the severity of arteriosclerosis, with the following results: Total cholesterol, 5.5 +/- 1.8 and 17.8 +/- 13.6 micrograms/mg wet weight (P < 0.05); triglyceride, 90.4 +/- 90.3 and 114.4 +/- 117.2 micrograms/mg wet weight (n.s.); and phospholipid, 7.4 +/- 3.9 and 11.2 +/- 3.9 micrograms/mg wet weight (P < 0.05), respectively, for the ITAs and LADs. These findings thus demonstrate that arteriosclerosis of the ITA in Japanese people is very mild, compared to that of the LAD in the same individuals.

Adult↗
PubMed1993

Biological monitoring of workers occupationally exposed to carbon disulphide in a rayon plant in Brazil: validity of 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine samples taken in different times, during and after the real exposure period.

Fifteen workers from a rayon plant in Brazil were monitored. Air samples were taken during a mean period of 5.8 hours out of an 8 hour workshift, in three different adsorbing tubes. Five urine samples were taken at 4 hour interval from the beginning of the shift, and at the beginning of the next shift in which 2-thiothiazolidine-4-carboxylic acid (TTCA) concentration was analysed. Data from seventeen "individuals" were statistically studied, with the aim of establishing the best and the most practical sampling strategy of biological monitoring for workers occupationally exposed to CS2. For those chronically exposed to CS2, TWA air concentration lower than 30 and higher than 10 mg/m3, it was found that the higher the exposure levels, the lower was TTCA concentration in the end of shift urine samples. The results may be explained by dietary habits and/or by the small number of examined population or even eventual casualty. On the other hand they raise other hypothesis involving the chronicity of exposure which may lead to important changes in metabolism influencing the excretion rate of TTCA.

Air Pollutants, Occupational↗
PubMed1993

Clinicopathological features and endoscopic diagnosis of superficial early adenocarcinomas of the large intestine.

From October 1987 to March 1991, 21 (8%) superficial early cancers were found among 256 early colorectal cancers (Dukes A and B1). Superficial early cancers were defined as early cancers less than 3 mm in height. These tumors were found scattered throughout the large intestine and were often observed as reddish spots, which were easily overlooked without careful observation. Histologically, 19 (90%) of them were well-differentiated adenocarcinomas, and five (24%) of them reached the submucosal layer. Eighteen (86%) of them were not associated with adenoma.

Adenocarcinoma↗
PubMed1993

Exercise coronary flow reserve of bilateral internal thoracic artery bypass grafts.

We attempted to quantify the exercise coronary flow reserve in 20 patients with bilateral internal thoracic artery grafts to the left coronary arteries (group I) who had complete revascularization. The coronary sinus blood flow was measured by the continuous thermodilution method both at rest and during exercise (50 W for 8 to 9 minutes) approximately 1 month after the operation. These results were compared with 30 patients treated with an internal thoracic artery and saphenous vein grafts to the left coronary arteries (group II) and 9 patients with saphenous vein grafts alone to the left coronary arteries (group III). There were no differences among the three groups in age, sex, number of vessels involved, heart rate, double products, left ventricular (LV) end-diastolic pressure, LV ejection fraction, LV end-diastolic volume, or LV mass at the time of study. None of the 59 patients in the study had abnormally enlarged LV end-diastolic volume or increased LV mass. The postoperative coronary sinus blood flow per 100 grams of LV mass at rest was similar among the three groups (73.0 +/- 28.4 mL/min per 100 g LV mass in group I, 73.4 +/- 31.1 mL/min per 100 g LV mass in group II, and 75.9 +/- 28.5 mL/min per 100 g LV mass in group III [not significant]) and significantly (p < 0.01) increased by exercise, although the differences between groups during exercise were not significant (158.9 +/- 45.9, 153.5 +/- 72.1, and 148.3 +/- 60.0 mL/min per 100 g LV mass, respectively [not significant]).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Pressure↗
PubMed1993

Lower extremity ischemia secondary to internal thoracic-coronary artery bypass grafting.

Vascular complications associated with the use of the internal thoracic artery as a conduit for coronary artery bypass are infrequent. However, acute limb-threatening ischemia can occur after the use of the internal thoracic artery for myocardial revascularization when this vessel forms an important collateral to an obstructed aortoiliac artery system. Although this is a rare complication, the consequences are devastating. Due to the risk of peripheral vascular insufficiency, we now perform simultaneous revascularization of the myocardium and the lower extremity when an internal thoracic artery that appears to be a major collateral to the ipsilateral aortoiliac system is used.

Acute Disease↗