Biomedical subjects

S Tanabe

Publications and source records attributed to S Tanabe.

At least 307 records · Page 17Linked to original sources

PubMed1991

Organochlorine pesticide and polychlorinated biphenyl residues in foodstuffs from Bangkok, Thailand.

Raw foodstuffs collected from Bangkok, Thailand, were analysed for the presence of PCBs, DDTs, HCHs (BHCs). HCB, aldrin, dieldrin, heptachlor and heptachlor epoxide. Residues of PCBs and organochlorine pesticides were detected in all the samples analysed. Concentrations of PCBs did not reach the tolerance limit set forth by the US Food and Drug Administration (FDA). The concentrations of SigmaHCH were higher than those of SigmaDDT in all the farm products while the levels of SigmaDDT were greater in fishes including fish flakes and fishmeal. Meat samples recorded higher concentrations of SigmaDDT and dieldrin than SigmaHCH. Comparing the levels of organochlorines in foodstuffs from Bangkok, considerable levels of aldrin and dieldrin indicate the need for concern from the food safety point of view because of their much higher toxicity than DDT and other organochlorines. However, the levels did not exceed the Maximum Residue Limit (MRL) recommended by FAO/WHO. Food contamination by HCB, heptachlor and heptachlor epoxide is comparatively lower.

Journal Article↗

PubMed1991

Determination of trace amounts of sulphide in human red blood cells by high-performance liquid chromatography with fluorimetric detection after derivatization with p-phenylenediamine and iron(III).

A high-performance liquid chromatographic method based on pre-column fluorescence derivatization has been developed for the determination of trace amounts of sulphide. After the sulphide had been converted into a fluorescent derivative, thionine, by the reaction with p-phenylenediamine and Fe3+, it was separated on a reversed-phase column and detected fluorimetrically (excitation, 600 nm; emission, 623 nm). Sulphide ion can be determined in the range from 0.01 to 3.0 mumol dm-3 with a relative standard deviation (n = 5) of 2.54% at 0.02 mumol dm-3 and 1.74% at 1.0 mumol dm-3. The proposed method was applied to the determination of sulphide in human red blood cells from ten healthy subjects, by generating sulphide in a microdiffusion apparatus; the concentrations found ranged from 0.123 to 0.189 mumol dm-3.

Chromatography, High Pressure Liquid↗

PubMed1991

Synthesis of protein C in human umbilical vein endothelial cells.

By monitoring the activation of protein C and the regulation of factor Xa-catalyzed thrombin formation by the activated protein C (APC) on the surface of human umbilical vein endothelial cells (HUVEC), we found that functional protein C was synthesized in cultured HUVEC and expressed thereon in the presence of vitamin K. Furthermore, without exogenously added protein S, time-dependent and saturable accumulation of APC (20 fmol APC/10(5) cells) on the surface of HUVEC was observed. During prothrombin activation by the complex of membrane-bound factor Xa and endogenous factor Va formed on the surface of HUVEC, APC was generated, and the rate of thrombin formation decreased. Treatment of HUVEC with an antibody that inhibits the APC-catalyzed inactivation of endogenous factor Va clearly quenched the activity of surface-associated APC. Immunostaining of HUVEC with a horseradish peroxidase (HRP)-conjugated antibody that solely recognizes human protein C confirmed the presence of protein C on the surface of HUVEC. Northern blot analysis revealed that an about 1.8 kb mRNA species derived from HUVEC was hybridized with 32P-labeled protein C cDNA, as in the case of those from HepG2, which are known to synthesize normal protein C. The increase in the amount of protein C mRNA in HUVEC in parallel with cell growth provided supporting evidence for the synthesis of protein C during the culture of HUVEC. These results indicate that blood coagulation is regulated by endogenously generated and activated protein C, together with or without protein S, through inactivation of factor Va on the surface of endothelial cells.

Antibodies, Monoclonal↗

PubMed1991

Vascularized omentum graft for the reconstruction of the skull base after removal of a nasoethmoidal tumor with intracranial extension: case report.

A 16-year-old boy with rhabdomyosarcoma occupying the nasal cavities and the ethmoid sinus with intracranial extension underwent transcranial surgery. The intradural tumor was resected first with the affected dura of the anterior skull base, and the dural defect was repaired with fascia harvested from the sheath of the rectus abdominis muscle. The remaining tumor contiguous to the nasal cavities was completely extirpated. The cranial cavity was then exposed to the opened nasal cavities, where a revascularized omental graft was used to separate these compartments. Lyophilized dura was placed beforehand beneath the omental graft, as a roof to the nasal cavity, and was removed 3 weeks later through the nostril. A bony skull base repair was performed over the omentum using the inner table of the bone flap. Subcutaneous fat from the abdomen was placed on the bone graft for fixation and as an additional seal for the dural defect. Reconstruction of the anterior skull base with a vascularized omental transfer provides an efficient barrier to the nasal cavity. It also serves as an excellent supporting structure for regeneration of the mucosal epithelium of the nasal cavities.

Adolescent↗

PubMed1991

Aging escalates baroreceptor reflex suppression by the posterior hypothalamus in rats.

To examine whether baroreceptor reflex regulation by the posterior hypothalamus becomes modified with age, we compared baroreceptor reflex sensitivity and hypothalamic responsiveness in 2- and 10-month-old rats anesthetized with urethane-chloralose. Hypothalamic regulation of baroreceptor reflex sensitivity was assessed by recording responses to intravenously infused phenylephrine and afferent aortic nerve stimulation after sham operation or electrolytic destruction of the posterior hypothalamus. Regardless of age, reflex bradycardia and sympathoinhibition elicited during pressor responses to phenylephrine, as well as all cardiovascular and sympathetic nerve responses to afferent aortic nerve stimulation, were stronger in rats with bilateral hypothalamic lesions than in age-matched, sham-operated controls. Distinctively, because baroreceptor reflex sensitivity differed with age only in sham-operated controls but not in lesioned rats, we concluded that age-related differences in baroreceptor reflex sensitivity had been abolished by posterior hypothalamic lesions. Other experiments were then performed to compare responses to graded electrical stimulation of the posterior hypothalamus in baroreceptor-intact rats. Pressor and sympathoexcitatory responses to hypothalamic stimulation were larger, and stimulus thresholds were lower at 10 than at 2 months of age thereby suggesting that hypothalamic responsiveness had increased with age. Our results are in accord with the interpretation that aging exacerbates the baroreceptor reflex suppression normally exerted by the posterior hypothalamus.

Aging↗

PubMed1991

Improved method for measurement of rhodanese activity using methanethiosulfonate as sulfur donor substrate and its application to human serum.

We have developed a sensitive method for the measurement of rhodanese activity in human serum which is based on the colorimetric method for the determination of thiocyanate produced from methanethiosulfonate and cyanide as substrates. Thiocyanate gives a red complex with ferric ion in an acidic condition. The present method is about 70-fold more sensitive than the conventional method using cyanide and thiosulfate as substrates and correlates well (r = 0.997) with the conventional method in bovine liver rhodanese. Within-run precision of the method is 0.91% for 420 units/l serum and the calibration curve is linear up to 1850 units/l. The normal value for human serum, determined by the present method on 31 healthy persons, was 20.9 +/- 20.0 units/l (mean +/- 2S.D.). Rhodanese activity was clearly elevated in some serum samples which were observed at abnormal values in some biochemical diagnostic tests and showed significant positive correlations with guanase activity (r = 0.728, p less than 0.01) and glutamic-oxalacetic transaminase activity (r = 0.625, p less than 0.01).

Humans↗

PubMed1991

[Interposition graft technique for the treatment of AAE (annuloaortic ectasia) with aortic regurgitation: surgical results].

Interposition graft technique had been used exclusively in 8 consecutive patients with AAE and AR. Two patients with severely dilated left ventricle (CTR 65, 80%, LVDd 93, 83 mm, LVDs 86, 68 mm), and 1 patient complicated with the postoperative mediastinitis died in the perioperative period, 10, 145 and 135 days after surgery, respectively. In the remaining 5 patients, excellent clinical improvement was observed with the reduction of CTR and echo-cardiographic findings without formation of hematoma, pseudoaneurysm, and leak from the suture lines on DSA and CT.

Adult↗

PubMed1991

[Pulmonary thromboembolectomy of subacute massive pulmonary thromboembolism in a patient with familial antithrombin III deficiency].

Reported is a case of successful pulmonary thromboembolectomy and inferior caval vein interruption in a patient with subacute massive pulmonary thromboembolism (PTE). He had been complicated by the right atrial and deep vein thrombosis due to type I familial antithrombin III (ATIII) deficiency. Pulmonary embolectomy and caval interruption was performed 20 days after the initial attack and followed by anti-coagulation therapy. Thrombi weighed 50 gm were removed mainly from the left pulmonary artery. The right atrial thrombus which had got smaller by the preoperative fibrinolytic therapy could not be found with right atriotomy. Respiratory function at rest and slightly elevated pulmonary arterial pressure was normalized post-operatively. Although the PTE in this patient was considered to be subacute by the histological findings of the fibrin thrombus removed, tapering of pulmonary arteries in PAG and obstructive intimal hypertrophy of the small vessels in the lungs suggests the chronic nature of the PTE (post-thrombotic obstruction of pulmonary arteries) caused by the hyper-coagulable state. In patients with familial ATIII deficiency, 50% of normal ATIII activity can be expected because they are heterozygotes, so the cardio-pulmonary bypass should be run with special caution to the heparin dosage. Caval vein interruption and warfarin therapy are recommended for prophylaxis of recurrent PTE.

Antithrombin III Deficiency↗

PubMed1991

[Cavernous malformation of the brain stem: clinical symptom and its surgical indication].

Clinical features and surgical indication of cavernous malformation (CVM) of the brain stem are reviewed, based on the analysis of five personally encountered cases and nineteen previously reported cases. Nineteen out of these twenty four cases presented sudden onset of neurological deficits suggesting brain stem hemorrhage. Although the majority of those patients with acute onset improved gradually within a couple of weeks, all cases, except for six cases treated with radical removal following their first bleeding episodes, presented recurrent hemorrhages, and one third of them died due to the repeated hemorrhages. The other six cases presented progressive neurological deficits with insidious onset. They were first diagnosed as brain stem gliomas or multiple sclerosis. All except two cases treated with radical removal of the CVM died within a year. Surgical indication of the cerebral CVM is still controversial, because its clinical presentations and natural history have been unclear. Recent clinical application of magnetic resonance imaging enables us not only to make a preoperative diagnosis accurately, but also to evaluate the operability in relation to its anatomical location. Because of an apparent disposition towards repeated hemorrhages, surgical removal should be considered for the symptomatic CVM in the brain stem, on which microsurgical manipulation would be possible with an acceptable risk in many cases.

Adult↗

PubMed1990

Amplified and rearranged bcl-2 gene in two lymphoma cell lines, FL-218 and FL-318, carrying a 14;18 translocation.

Two human B-cell lines carrying a 14;18 chromosome translocation [t(14;18)(q32;q21)], designated FL-218 and FL-318, were established from effusion cells of two Japanese patients manifesting the transformed histology of follicular lymphoma. The FL-218 and FL-318 cell lines were composed of cells in the hyperdiploid range, which had two and three or four 18q- chromosomes, respectively. These 18q- chromosomes were not distinguishable from an 18q- chromosome derived from t(14;18) since they exhibited the same banding pattern. Southern blot analysis revealed that in both cell lines, breakage of the bcl-2 gene occurred within the major breakpoint cluster region and the truncated gene juxtaposed to an immunoglobulin heavy chain gene locus. The autoradiographic intensity of the retained fragment each on 18q- chromosome was more enhanced than that of the translocated fragment on 14q+ chromosome. These findings suggest that the extra 18q- chromosome found in t(14;18)-positive cancer does not arise from de novo independent t(14;18) but from duplication of a preexisting 18q- chromosome.

Aged↗

PubMed1990

Enzymatic assay of 3-mercaptopyruvate sulfurtransferase activity in human red blood cells using pyruvate oxidase.

A highly sensitive method has been developed for the determination of 3-mercaptopyruvate sulfurtransferase (EC 2.8.1.2) activity in human red blood cells which is based on the colorimetric method for the determination of pyruvate using the coupled color enzymatic reaction with pyruvate oxidase (EC 1.2.3.3) and peroxidase (EC 1.11.1.7). The absorbance increase of the coupled color of N-ethyl-N-(2-hydroxy-3-sulfopropyl)-m-toluidine and 4-aminoantipyrine at 555 nm is proportional to sulfurtransferase activity. The present method is more than 10-fold more sensitive and more reproducible than the usual methods, and does not require centrifugation, filtration, and neutralization steps. The calibration curve is linear up to 450 units/liter and the precision per run is 1.06% for 77.5 units/10(10) red blood cells (n = 10). Comparison with the lactate dehydrogenase method gave good correlation (r = 0.995). The normal value for the human red blood cell enzyme, determined with the present method on 30 healthy persons, was 63.8 +/- 14.4 units/10(10) cells (mean +/- 2SD).

Colorimetry↗

PubMed1990

Seasonal variation of persistent organochlorine insecticide residues in Vellar River waters in Tamil Nadu, South India.

Water samples collected from Vellar river and Pichavaran mangroves at Porto Novo (11 degrees 29' N, 79 degrees 46' E), Tamil Nadu State, South India, from December 1987 to January 1989 were analyzed to determine the seasonal variation of the levels of organochlorine insecticides such as HCH (BHC) and DDT. Both these insecticides showed higher levels from October to February, although this trend was more pronounced in HCH than DDT, reflecting the application of technical HCH largely and probably small quantities of DDT during the flowering season of rice. The alpha-HCH was detected as a dominant isomer for all seasons monitored followed by beta-HCH. Among DDT compounds, p,p'-DDT was the highest in river water except in the dry season when p,p'-DDD showed a higher percentage. On the other hand, in mangroves p,p'-DDE was highest during the wet season and p,p'-DDD during the dry season. Air-water partitioning data of HCH isomers and DDT compounds in Vellar river revealed that these chemicals tend to be in the water phase. These observations may aid in understanding the role of a tropical paddy area on the behavior and fate of man-made chemicals in view of worldwide contamination.

Journal Article↗

PubMed1990

Allosteric potentiation of quisqualate receptors by a nootropic drug aniracetam.

1. Allosteric potentiation of the ionotropic quisqualate (iQA) receptor by a nootropic drug aniracetam (1-p-anisoyl-2-pyrrolidinone) was investigated using Xenopus oocytes injected with rat brain mRNA and rat hippocampal slices. 2. Aniracetam potentiates the iQA responses induced in Xenopus oocytes by rat brain mRNA in a reversible manner. This effect was observed above the concentrations of 0.1 mM. Kainate. N-methyl-D-aspartate and gamma-aminobutyric acid responses induced in the same oocytes were not affected. 3. The specific potentiation of iQA responses was accompanied by an increase in the conductance change of iQA and alpha-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) responses, but the affinity of receptors for agonist and the ion-selectivity of the channels (reversal potentials) were not changed. 4. Aniracetam reversibly potentiated the iQA responses recorded intracellularly from the pyramidal cells in the CA1 region of rat hippocampal slices. The excitatory postsynaptic potentials (EPSPs) in Schaffer collateral-commissural-CA1 synapses were also potentiated by aniracetam. 5. Population EPSPs recorded in the mossy fibre-CA3 synapses as well as Schaffer-commissural synapses were also potentiated by aniracetam. The amplitudes of the potentiation were not changed by the formation of long-term potentiation.

Action Potentials↗

PubMed1990

Baroreceptor reflex enhancement by chronic intracerebroventricular infusion of enalapril in normotensive rats.

Involvement of the brain renin-angiotensin system in baroreceptor reflex regulation was assessed by recording reflex heart rate and sympathetic nerve responses in normotensive rats that had been infused intracerebroventricularly with the converting enzyme inhibitor enalapril for 15 days. Reflex bradycardia and sympathetic nerve inhibition during pressor responses to phenylephrine were larger in rats with intracerebroventricularly infused enalapril than in control rats similarly infused either intracerebroventricularly with saline or intravenously with enalapril. In contrast, opposite reflex responses to sodium nitroprusside-induced hypotension were mostly unaffected. Because depressor, bradycardic, and sympathoinhibitory responses to electrical stimulation of the central cut end of the left aortic depressor nerve were also enhanced, intracerebroventricularly infused enalapril must be affecting the baroreceptor reflex arc centrally. These results are compatible with the interpretation that intracerebroventricularly infused enalapril enhanced baroreceptor reflex sensitivity by reducing endogenous angiotensin II levels in the brain through converting enzyme inhibition.

Afferent Pathways↗

PubMed1990

Metabolic pathways of sodium bisulfite injected intravenously in rabbits.

The metabolites of sodium bisulfite in rabbits through intravenous injection were examined according to the high performance liquid chromatography method for determination of sulfur-containing substances. Most of the administered sulfite was oxidized to sulfate, and a small part was converted to thiosulfate, S-sulfoalbumin, S-sulfoglutathione and S-sulfocysteine. Furthermore, it was found that S-sulfocysteine administered intravenously to a rabbit was partially changed to inorganic sulfate and thiosulfate. These metabolites produced from sulfite in rabbits indicated the presence of the many and complicated metabolic pathways of sulfite in vivo.

Animals↗

PubMed1990

[Effect of ulinastatin (UL) on renal function and lactic acidosis during open-heart surgery: comparison with aprotinin (Ap)].

Comparison was made on the renal function and lactic acidosis during cardiopulmonary bypass (CPB) between the group Ul (n = 15) and group Ap (n = 27). A 300,000 u, of ulinastatin was administered intravenously before CPB and 300,000 u, in the prime solution. A 300,000 u, of aprotinin was administered in the prime solution. Urine output during CPB was not significantly different, but the total dose of furosemide administered was less in group Ul and a significant difference (p less than 0.05) was observed in the free water clearance at CPB 1 hr. and 3 hr. postoperatively, -0.83 +/- 0.16 and -1.74 +/- 0.14 in group Ul and -0.43 +/- 0.10, -0.99 +/- 0.14 in group Ap, respectively. Arterial lactate increased as the perfusion time increased but the level at the end of CPB was significantly lower (p less than 0.05) in group Ul and the added 7% NaHCO3 to correct metabolic acidosis during CPB of 29.3 +/- 9.5 ml in group Ul was less than in group Ap of 82.2 +/- 15.2 ml (p less than 0.01). The result suggests the favourable effects of ulinastatin on the renal function and lactic acidosis during CPB.

Acidosis, Lactic↗

PubMed1990

[Left ventricular-right atrial communication following mitral valve replacement].

A case of an acquired left ventricular-right atrial communication complicating Omnicarbon replacement of a severe calcified mitral valve in the area of the posteromedial commissure is reported. The intricate relationships of the membranous atrioventricular septum to the mitral valve and the tricuspid valve predispose to the creation of an iatrogenic left ventricular-right atrial fistula when aggressive debridement of extensive valvular calcification is performed. Emphasis is placed on the diagnosis, and immediate surgical repair is advocated as soon as this complication is discovered.

Female↗

PubMed1990

[Indication for surgery in a patient with tuberculoma accompanied by chronic myeloid leukemia].

Patients with chronic myeloid leukemia (CML) tend to suffer from non-reactive form of tuberculosis (TB) and often dissemination and death are the consequence when the blast crisis occurs. In those patients the eradication of pulmonary TB is essential to prolong their life. In a 58-year-old man with a tuberculoma and CML, right upper lobectomy was performed and was discharged 2 weeks later uneventfully. He succumbed to blast crisis 59 months after the onset of CML with no autopsy finding of recurrence nor dissemination of TB. The lobectomy in this patient was effective in preventing dissemination of TB. Controversy exists as to the indication for surgery but this case illustrates the effectiveness of surgery preventing the dissemination of TB in patients accompanying CML.

Humans↗