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Biomedical subjects

S Tsukamoto

Publications and source records attributed to S Tsukamoto.

At least 73 records · Page 4Linked to original sources
PubMed1998

Determinations of free and bound ethanol, acetaldehyde, and acetate in human blood and urine by headspace gas chromatography.

The improved PCA method leads to accurate measurement of ethanol, acetaldehyde, and acetate in blood and urine by headspace gas chromatography. It is important to prevent the formation of artifactual acetaldehyde from coexistent ethanol. The column used for detection of alcohol metabolites was the fused silica glass capillary column bonded with PEG-20M or the fused silica glass capillary column of Pora PLOT Q. In bound alcohol metabolites, recent measurements of hemoglobin-associated acetaldehyde in blood, and ethanol conjugate and acetaldehyde conjugate in urine are reviewed and described as a marker of alcohol abuse.

Acetaldehyde↗
PubMed1998

Macroscopic aspects of cloth-covered Starr-Edwards prostheses at reoperation: what the precursory valve teaches us.

BACKGROUND AND AIMS OF THE STUDY: Cloth-covered Starr-Edwards ball valves were the first choice in prosthetic substitution at the authors' institution between June 1968 and March 1977. This study investigated, retrospectively, macroscopic aspects of the prostheses at reoperation. METHODS: Among 59 survivors who underwent isolated aortic or mitral valve replacement, 12 required reoperation for valve dysfunction (five aortic valve replacements, seven mitral valve replacements). Reoperation was necessitated by valvular endocarditis, paravalvular leak, hemolysis, thromboembolism, orifice stenosis attributable to pannus, and inappropriate sizing related to growth and thrombus. The mean time to reoperation was 11.7 +/- 6.2 years after initial surgery (range: 2 years 4 months to 21 years 8 months). RESULTS: Marked cloth wear was observed in all aortic prostheses, but only slight wear in mitral valves. Pannus formation was observed around the orifice in both aortic and mitral prostheses, but strut cloth was not extensively covered by autologous tissue. In mitral valves, strut cloth was only slightly worn and less loose than that of the aortic valve. These changes notably affected prosthetic valve function, the most significant problem in mitral prostheses being thrombus (four of seven valves). CONCLUSIONS: Pannus formation and thrombus caused by the reaction of the patient's tissues remain major problems in the use of artificial valves, and require further work for their improvement.

Adolescent↗
PubMed1998

Post-operative effects of olprinone after coronary artery bypass grafting.

The aim of this study was to test the effects of olprinone after coronary artery bypass grafting (CABG). In order to prevent hypotension caused by olprinone, low doses of catecolamines were used concomitantly. Total 22 elective CABG cases were evaluated. In all cases, moderate hypothermia and cardioplegic cardiac arrest were performed. In 10 cases, continuous intravenous 0.1 microg/kg/min of olprinone, 3 microg/kg/min of dobutamine (DOB) and dopamine (DOA) as the initial doses, were used concomitantly (Group I). As a control, the same initial doses of catecolamine (DOB and DOA) of Group I were administered in another 12 patients (Group II). When the pump flow of cardiopulmonary bypass (CPB) was decreased to half, these drugs were administered in both groups. Hemodynamics were recorded before CPB, just after the operation and 3, 6, 12, 24, 48, and 72 hours after the operation. Three hours after the operation, both mean aortic pressure (AoP) and pulmonary artery pressures (PAP) of Group I demonstrated significantly lower values than those of Group II. Cardiac index (CI) of Group I showed significantly higher values than that of Group II until 6 hours after surgery. The systemic vascular resistance index (SVRI) of Group I indicated a significantly lower value than that of Group II until 24 hours after the operation. Pulmonary capillary wedge pressure (PCWP) of Group I demonstrated a significantly lower value than that of Group II. There were no significant differences in urine output, oxygen delivery (DO2) and oxygen consumption (VO2) between both groups. Olprinone increased CI and decreased SVRI, and it showed easy weaning from CPB, demonstrating excellent hemodynamics after CABG. These results suggested that this new phosphodiesterase inhibitor may be effective for not only weaning from CPB but also post-cardiotomy cardiogenic shock.

Aged↗
PubMed1998

Congenital coronary artery fistula treated surgically in the right atrium and the atrial septum.

Various surgical techniques have been employed according to the type of the coronary fistula. In this case, preoperative examinations by aortography and MRI revealed a coronary artery fistula which originated from a site just proximal of the RCA, ran through the interatrial septum and drained into the posterior wall of right atrium. The ratio of pulmonary to systemic blood flow (Qp/Qs) was 1. 95. During surgery, we were not able to ligate or divide the fistula on the cardiac surface because the fistulous vessel originated from the posterior aspect of the proximal RCA. After establishing a cardiopulmonary bypass, the opening of the fistula in the right atrium was closed with an autologous pericardium patch, the surface of the interatrial septum was incised and the fistula was identified. The conduit was then divided and closed in the atrial septum. The postoperative course was uneventful. This approach is able to interrupt the fistula safely without interfering with normal coronary flow. Closure of the outlet and division of the fistula itself is a recommendable method to insure interruption of fistulous communication.

Adult↗
PubMed1997

N-[2-[(substituted chroman-8-yl)oxy]ethyl]-4-(4-methoxyphenyl)butylamines: synthesis and wide range of antagonism at the human 5-HT1A receptor.

A series of N-[2-[(substituted chroman-8-yl)oxy]ethyl]-4-(4-methoxyphenyl)butylamines was prepared and examined for their 5-HT1A receptor antagonist activity. The parent compound 3a and seven analogs bearing five kinds of substituents on the chroman ring were prepared from the corresponding 8-hydroxychroman intermediates. Radioligand binding assays proved the compounds 3a-h to have high affinity for the rat hippocampal 5-HT1A receptor with varied selectivity for adrenaline alpha1 and dopamine D2 receptors. Their antagonism was evaluated in a forskolin-stimulated adenylate cyclase assay performed with CHO cells expressing the human 5-HT1A receptor. Among the series, the C6-fluoro analog 3c showed both extremely potent affinity (Ki = 0.22 nM) and antagonism (EC50 = 13 nM) for the 5-HT1A receptor. Correlation analysis using substituent descriptors revealed a linear and negative correlation between molar refractivity of the C6-substituent and the binding affinity expressed in pKi.

Animals↗
PubMed1997

Post-ischaemic treatment with orotic acid prevents neuronal injury in gerbil brain ischaemia.

We studied the effects of orotic acid, a precursor of pyrimidine nucleotide, on delayed neuronal death of hippocampal CA1 neurones induced by global cerebral ischaemia in Mongolian gerbils. Neuronal damage was significantly reduced in animals treated with orotic acid 2 h before ischaemia at doses of 100, 200 or 300 mg kg-1, i.p. A dose of 300 mg kg-1 given 24 h after ischaemia also suppressed CA1 neuronal damage, but had no effect when given at 48 or 72 h. These results demonstrate a protective effect of orotic acid on ischaemic neuronal damage with a wide therapeutic time window.

Animals↗
PubMed1997

Ooplasmic round spermatid nuclear injection procedures as an experimental treatment for nonobstructive azoospermia.

PURPOSE: Our objective was to apply ooplasmic round spermatid nuclear injections for the treatment of nonobstructive azoospermia. MATERIALS: Participants were nine azoospermic men who had previously undergone diagnostic testicular biopsy. Spermatogenetic arrest was diagnosed at the round spermatid stage (n = 6) or primary spermatocyte stage (n = 3). A second (therapeutic) testicular biopsy was performed and round spermatid nuclei were recovered from all the participants. RESULTS: Forty-nine mature oocytes were successfully injected with nuclei and then cultured for 72 hr. Twenty-four embryos were transferred to nine women. No pregnancy was achieved. CONCLUSIONS: Round spermatids can be recovered from therapeutic testicular biopsy material of men negative for round spermatids in previous routine diagnostic testicular biopsy specimens. Round spermatid nuclear injections may play a role in the treatment of nonobstructive azoospermia.

Adult↗
PubMed1997

Tumor necrosis factor-induced, superoxide-mediated neutrophil accumulation in cold ischemic/reperfused rat liver.

The mechanisms of hepatic ischemia/reperfusion injury are complicated and multifactorial. This study was designed to examine superoxide generation and neutrophil accumulation in cold ischemic-reperfused rat livers after elimination of Kupffer cells and to determine the role of superoxide/tumor necrosis factor (TNF) interactions. Rat Kupffer cells were eliminated by liposome-encapsulated dichloromethylene diphosphonate injected intravenously. Livers from control and treated rats were isolated and preserved in University of Wisconsin solution (4 degrees C) for 0, 12, and 24 hours and then perfused for 60 minutes with oxygenated Krebs-Henseleit bicarbonate buffer (37 degrees C) by adding neutrophils into the perfusate. Superoxide generation was measured by using real-time chemiluminescence (CL) during perfusion, and neutrophil accumulation was assessed by measuring myeloperoxidase activity in the liver tissue. In the control livers, CL intensity markedly increased on reoxygenation, and after neutrophil infusion it increased again with a lag period of 10 minutes. Total CL intensity and myeloperoxidase activity increased with the duration of cold preservation. TNF release into the effluent perfusate was detectable only after 24 hours of preservation, and lactate dehydrogenase release was high. Elimination of Kupffer cells attenuated CL intensity and TNF and lactate dehydrogenase release and resulted in reduced myeloperoxidase activity. Electron microscopy revealed amelioration of hepatocyte swelling and endothelial cell disruption when Kupffer cells were eliminated. After 24 hours of preservation, superoxide generation was inhibited in the control livers by anti-TNF antiserum, whereas TNF release was not inhibited by superoxide dismutase. These results suggest that TNF induces superoxide generation by Kupffer cells, which mediates neutrophil accumulation and causes cellular injury in the initial phase of reperfusion.

Animals↗
PubMed1997

[A developmental study on children's understanding of emotion and emotional self-control].

The present study examined how children understand the processes concerning the strategic control of emotion. There are five components of this emergent metaemotive understanding: the children's knowledge of (1) the cues for identifying emotions, (2) the antecedents of emotions, (3) display rules, (4) the consequence of an emotional response, and (5) the strategies of emotional self-control. Five, seven and nine-year-old children were interviewed regarding their knowledge of these components. The following results were obtained. For identifying emotion, seven-year-olds tended to focus on the situational cues. Nine-year-olds were more likely to focus on the mental cues. The frequency of spontaneous usage of display rules increased with age. Nine-year-olds mentioned the cognitive self-control strategies such as re-directing their thoughts. The results were discussed in terms of developmental perspectives.

Child↗
PubMed1997

[Urgent replacement of aortic arch and descending aorta following replacement of ascending aorta for Stanford a aortic dissection--a case report].

A 37-year-old male who was on chronic dialysis regimen for IgA nephropathy developed acute Stanford A type aortic dissection. Replacement of the ascending aorta was performed with the aid of extracorporeal circulation, selective cerebral perfusion, and open distal anastomosis technique. The site of the intimal tear in the ascending aorta was resected and the gelatin-resorcin-formaldehyde (GRF) glue was applied to both stumps. The outside of dissecting aortic wall was reinforced with Teflon-felt strips. Two months after the operation, the patient required an urgent operation due to threatening spindle evolution of a persisting dissection in the descending aorta. Replacement of the total arch and the descending aorta was carried out via the median sternotomy with the left anterior thoracotomy, and a subclavian incision. Continuous veno-venous hemofiltration was initiated immediately after both operations and the water balance was maintained well. The patient was discharged 1 month postoperatively. It was suggested that the inside of the dissected aortic wall should be also reinforced even when the GRF glue was used in patients who have a fragile intimal flap and a wide tear.

Acute Disease↗
PubMed1997

[Effect of long-term ethanol administration (2). Free type and bound type ethanol and related substances contents of the urine from ethanol administrated rats, indices in the serum, and renal tissues].

Histological effects of ethanol on the kidney were published in our previous report. In the present paper, results of the following measurement will be reported: contents of ethanol and related substances in the urine, both free and bound types, collected during the periods from 30 minutes to 11 hours after ethanol administration to rats, and ACE, alpha-GST, LPO, 25(OH)-D3, 1 alpha-25(OH)2-D3, 24, 25(OH)2-D3 in the serum of rats which had ethanol every day for a month. These will be reported together with histological observation of the kidney excised immediately after the blood sample was collected. The measurement of free and bound types ethanol, acetaldehyde, acetone and methanol in the urine was made up to 11 hours after administration of 4 g/kg b.w./day, p.o. and its results showed the highest contents at 9 hours after the administration. Bound type acetic acid showed the high contents at both 90 minutes and 9 hours after the administration. In 11 hours free type ethanol and acetaldehyde recovered their pre-administration value but as to the bound type only acetic acid recovered it. In the serum of the rats which were ethanol 4 g/kg b.w./day, oral administrated for a mouth, ACE showed significantly high value and 1 alpha, 25(OH)2-D3 and 24, 25(OH)2-D3 showed significantly low value relative to the control. Also alpha-GST showed a low value. In the kidney of the same rats the following changes were observed: swelling of glomerulus, thickening of basement membrane of glomerulus, PAS positive deposits in glomerulus, proliferation of mesangial cell, proliferation of juxtaglomenular cell, dilation of tubular lumen, swelling of tubular epithelial cell, its falling, hyaline droplet in tubular epithelial cell, cell infiltration to interstitial tissue, and basophilic tubule. There was not only difference between findings in the control and those in the liver and the brain of the rats which showed changes above-mentioned. As described above, changes were seen in the renal tissue caused by ethanol administration and in this connection changes in indices related to renal function were observed, too. Furthermore, urinary ethanol and related substances, not only free type but also bound type, that went through the kidney were observed for a long period time. The bound type, in particular, was observed for longer duration and hence effects of ethanol on the kidney were surely assumed. Presently longer term experiments are proceeding and other indices connected with renal functions are being studied.

Administration, Oral↗
PubMed1997

[Three-dimensional transesophageal echocardiographic assessment for prosthetic valves].

We evaluated three-dimensional transesophageal echocardiographic assessment of the implanted mechanical valves by rotational scanning method. Patients were 7 mitral valve replacement and one aortic valve replacement, 2 mitral and aortic valve replacement. In 2 cases of 7 mitral valve replacement, the prosthetic valve regurgitation was evaluated using by color Doppler echocardiography. In this study, multiplane transesophageal probe was used. It rotated at 2-degree intervals from 0 to 180 degrees and the three-dimensional reconstruction was performed by echo scan workstation system (TOMTEC Inc, Munich, Germany). In mitral valve replacement cases, the valve motion of bileaflet valve (St. Jude Medical valve and ATS valve) were showed very clearly. The struts was easily recognized in the St. Jude Medical valve (SJM valve) cases. In one of SJM valve cases, the pannus formation was revealed, but it did not disturb valve motion. The prosthetic valve regurgitation can be seen accurately. However, aortic valve and ball valve cases cannot be reconstructed because of artifact from prosthetic valve and ultrasonic direction. The prosthetic valve regurgitation, pannus formation which was difficult to be showed in two-dimensional echocardiography and relationship between annulus and sewing cuff can be evaluated by this three-dimensional echocardiography. In this study, this system has some problems, for example real-time evaluation is impossible, aortic valve and ball valve cases cannot be reconstructed. However, we think that this new technology is suitable for evaluating valve thrombus, valve dysfunction and paravalvular leakage. In conclusion, the three-dimensional echo-cardiography demonstrated, reliable and accurate examination, and it can evaluate various complications of prosthetic valve.

Adult↗
PubMed1996

Dopamine D3 and D4 receptor antagonists: synthesis and structure--activity relationships of (S)-(+)-N-(1-Benzyl-3-pyrrolidinyl)-5-chloro-4- [(cyclopropylcarbonyl) amino]-2-methoxybenzamide (YM-43611) and related compounds.

In this study, we synthesized a series of (S)-N-(3-pyrrolidinyl)benzamide derivatives, 1, 2a-d, 5a-1, and 7, and their enantiomers, (R)-1 and (R)-5c-e, and evaluated their binding affinity for cloned dopamine D2, D3, and D4 receptors and their inhibitory activity against apomorphine-induced climbing behavior in mice. The results indicate that D2, D3, and D4 receptors have different bulk tolerance (D4 > D3 > D2) for the substituent of the 4-amino group (R1) on the benzamide nuclei and that cyclopropyl-, cyclobutyl-, and cyclopentylcarbonyl groups likely possess adequate bulkiness with respect to D3 and D4 affinity and selectivity over D2 receptors in this series. The results also suggested that the N-substituent (R2) on the pyrrolidin-3-yl group performs an important role in expressing affinity for D2, D3, and D4 receptors and selectivity among the respective subtypes. One of the compounds, (S)-(+)-N-(1-benzyl-3-pyrrolidinyl)-5-chloro-4-[(cyclopropylcarbonyl+ ++) amino]-2-methoxybenzamide (5c) (YM-43611), showed high affinity for D3 and D4 receptors (Ki values of 21 and 2.1 nM, respectively) with 110-fold D4 selectivity and 10-fold D3 preference over D2 receptors and weak or negligible affinity for representative neurotransmitter receptors. Compound 5c displayed potent antipsychotic activity in inhibiting apomorphine-induced climbing behavior in mice (ED50 value, 0.32 mg/kg sc).

Animals↗
PubMed1996

An efficient short-step total synthesis of ganglioside GM3: effective usage of the neighbouring group participation strategy.

We have developed an efficient methodology for highly stereoselective sialylation using 3-position substituted sialic acids and have prepared 2a having a 3 beta-phenylthio group as a sialic donor. Glycosylation of suitably protected lactoside 3 with 2a gave only the alpha-sialyl trisaccharide 16 in good yield. Condensation of the azidosphingosine 4 with the acetate 17 using promotors, DMTST or NIS-TfOH, afforded the glycolipid 18, which was directly transformed to 20 by reduction with Bu3P and subsequent acylation with octadecanoic acid in the presence of WSC. Removal of the protecting groups generated ganglioside GM3 (1).

Carbohydrate Sequence↗
PubMed1996

Why is liver preservation performed at 4 degrees C?

To establish the most suitable temperature for liver preservation, we preserved rat livers at various temperatures (0, 5, 10, and 15 degrees C) in UW solution and investigated, biochemically, the proton ATPase activity, ATP metabolites in mitochondria, and phosphatidyl-choline hydroperoxide (PC-OOH) in liver tissue. Liver specimens were taken every 6 h up to 24 h. The proton ATPase activity and the concentration of ATP, ADP, AMP, and adenosine in livers preserved at 0 degree C showed the best results. The total adenine nucleotide (TAN) in livers preserved for 18 and 24 h had significantly higher concentrations compared with those at other temperatures (5, 10, and 15 degrees C). In the livers preserved at 5 degrees C, TAN was degraded to hypoxanthine. On the other hand, those preserved at both 10 and 15 degrees C showed changes from hypoxanthine to xanthine. The concentration of xanthine in both groups preserved at 10 and 15 degrees C showed high values at 6 and 12 h, respectively, and similar changes in PC-OOH concentrations at both 10 and 15 degrees C were observed. However, the changes in PC-OOH concentration at various temperatures were not significant for any length of preservation time. In light microscopical examinations, there were no morphological changes in the hepatocytes. From these results, we conclude that the capability of ATP synthesis of mitochondria in livers preserved at 0 degree C keep them in the best condition compared with livers preserved at 15, 10, and 5 degrees C.

Adenine Nucleotides↗
PubMed1996

Ciliary body band width as an indicator of goniodysgenesis.

PURPOSE: To evaluate the gonioscopic signs indicative of underdevelopment of the iridocorneal angle and thereby obtain a correct diagnosis of goniodysgenetic glaucoma. METHODS: We examined morphologically the iridocorneal angle of 28 enucleated human eyes, including those from premature infants as well as from older subjects. The ratio of the ciliary body band width to the width of the posterior limbus (the distance between the termination of Descemet's membrane and the iris root), termed the theoretic C/L ratio, was calculated by drawing on light micrographs. Data were compared for three age groups: premature infants, children, and subjects older than 9 years. We also examined clinically the appearance of the ciliary body band on gonioscopy in 135 eyes of 69 younger patients having primary glaucoma with open iridocorneal angles and in 94 eyes of 47 age-matched control subjects. RESULTS: The theoretic C/L ratio +/-SD was 1.4% +/- 2.7% in premature infants, 24.0% +/- 5.4% in children, and 36.7% +/- 8.0% in the older subjects. There was a statistically significant difference between each of the three groups (between premature infants and children, P < .001; between children and older subjects, P < .005; between premature infants and older subjects, P < .001). On gonioscopy, 105 of 135 glaucomatous eyes (77.8%) and 13 of 94 control eyes (13.8%) showed either an invisible or very narrow ciliary body band (P < .0001). CONCLUSION: The ciliary body band seen on gonioscopy provides an indicator of the development of the iridocorneal angle. An invisible or very narrow ciliary body band represents an underdevelopment of the angle.

Adolescent↗