Biomedical subjects

S Higashi

Publications and source records attributed to S Higashi.

At least 127 records · Page 7Linked to original sources

PubMed1994

Electron microscopic studies on Sharpey's fibers in the alveolar bone of rat molars.

The fine structure of Sharpey's fibers in the alveolar bone of rat molars were observed by electron microscope. The fixed samples were three-dimensionally observed with a scanning electron microscope (SEM) after NaOH treatment. The penetrating Sharpey's fibers in the alveolar bone appeared distinctly. The fibers penetrated straight and/or branched in the alveolar bone. The Sharpey's fiber bundles ran nearly perpendicular to the bone matrix fiber bundles. The other fixed samples were embedded in polyester resin, ground and observed by backscattered electron signals in an SEM (BSE). In the BSE images, even thin Sharpey's fibers deeply penetrating the alveolar bone were hypomineralized. The fine ultrastructure of fibers were also observed by a transmission electron microscope (TEM). It was suggested that the three-dimensional structure of Sharpey's fibers intensified the continuity between the periodontal ligament fiber and the alveolar bone and consisted of a buffer medium against stress.

Animals↗

PubMed1994

[A case report of the maze procedure with mitral valve replacement].

The maze procedure was performed simultaneously with mitral valve replacement for atrial fibrillation and mitral stenosis in a 66-year-old female. On the first postoperative day, the cardiac status deteriorated suddenly due to a very rapid heartbeat which was later diagnosed as a 1:1 AV conduction of atrial flutter. The atrial flutter responded to an injection of verapamil and changed to a 2:1 conduction. Although atrial flutter had continued until the thirteenth postoperative day, the heart achieved sinus rhythm on that day. Since then it has continued without any antiarrhythmic drugs except digitalis. It was difficult to make a diagnosis of the rapid heartbeat on the 12-lead ECG because P waves could not be seen clearly on the ECG. Recording the electrical cardiac status by using the temporal atrial pacing leads, which were placed during the operation, was helpful in diagnosing the heartbeat as atrial flutter. The electrophysiological examination eight weeks after the operation revealed that the sinus node function was normal and atrial flutter or atrial fibrillation could not be induced. The patient is well and in sinus rhythm 12 months after the operation.

Aged↗

PubMed1994

Alcohol ingestion enhances hepatocarcinogenesis induced by synthetic estrogen and progestin in the rat.

We examined the effect of alcohol ingestion on rat hepatocarcinogenesis induced by oral administration of synthetic female hormones, 0.075 mg of ethynylestradiol (EE) and 6.0 mg of norethindrone acetate (NA), everyday for 12 months to Wistar rats. Concomitant administration of 10% ethanol in drinking water resulted in the development of hepatocellular carcinoma (HCC) in 40.8% in female rats and 11.8% in male rats at 12 months, although the incidences of HCC following hormones administration alone were 8.0% in female rats and 0% in male rats. The incidence and the number of hyperplastic nodules in rats with concomitant alcohol treatment were significantly higher than that in rats with hormone treatment alone. The additional alcohol administration significantly increased the values of nuclear and cytosol estrogen receptors at 4 months. Synthetic female hormones and/or alcohol treatment also significantly increased the value of cytosol progesterone receptor at 4 months. 32P-postlabeling analysis of liver DNA revealed that alcohol enhanced the DNA adduct formation induced by hormones. Consequently, alcohol may affect rat hepatocarcinogenesis caused by synthetic female hormones in enhancing cell-proliferating activity via estrogen and progesterone receptors, and DNA adduct formation induced by synthetic female hormones.

Alcohol Drinking↗

PubMed1993

Development of antitissue factor antibodies in patients after liver surgery.

After liver surgery, two patients developed unexplainable prolonged prothrombin times (PT) that were not associated with bleeding tendency. The substitution of rabbit thromboplastin for either human or monkey thromboplastin in performing PT tests resulted in a normal clotting time. Tissue factor (TF) procoagulant activity assays and an immunoblotting analysis showed that these patients had developed IgG lambda-type immediate anticoagulants directed against both rabbit and bovine TF that did not crossreact with human or monkey TF. In a chromogenic assay, the patient IgG caused a decrease in both the Km and the Vmax of the factor X activation by rabbit TF-factor VIIa complex. The lack of reactivity of the patient IgG with human TF presumably explained why there was no clinical bleeding. Both patients had been treated earlier with a topical hemostatic agent prepared from bovine corium, microfibrillar collagen hemostat, while undergoing previous surgery. In an immunoblotting analysis, the patient IgG stained a 42-Kd band in the Triton extract of the collagen preparation under either reducing or nonreducing conditions. The Triton extract of the collagen preparation blocked the binding of the patient IgG to bovine TF. Thus, it is suggested that the iatrogenic immunization by intraoperative exposure of bovine TF retained in the collagen preparation may be responsible for the development of anti-TF antibodies in these patients. The anti-TF antibodies resulted in a clinical error in the evaluation of coagulation status after the use of rabbit thromboplastin.

Animals↗

PubMed1993

[CT finding of right diaphragmatic rupture due to blunt trauma--subhepatic hemothorax].

Owing to the poor detectability of the anatomic location of diaphragm on the parallel plane of computed tomography (CT), capability of CT to predict traumatic ruptured diaphragm has been debated in several reports. A specific hematoma (subhepatic hemothorax) adjacent to the posterior attachment of the right diaphragm was identified on CT. The finding originated from herniated liver that migrated to the posterior thoracic wall as a result of gravity, to separate the hemothorax in the supine position. This was surgically proven in two patients after blunt traumatic accident. The finding is useful in predicting right diaphragmatic rupture on CT study. The formation of subhepatic hemothorax, its differential diagnosis and a brief review of diaphragmatic rupture are discussed.

Adult↗

PubMed1993

Pharmacokinetics of (1R,2R-diaminocyclohexane)oxalatoplatinum(II) in comparison with cisplatin following a single intravenous injection in rabbits.

The pharmacokinetics of (1R,2R-diaminocyclohexane)oxalatoplatinum(II) (1-OHP, NSC-266046), a second-generation antitumor platinum complex, was studied in rabbits and compared with that of cisplatin. The rabbits were given a single i.v. dose of 1-OHP or cisplatin (10 mumol/kg). A comparison of tissue platinum levels at 24 h postinjection showed that platinum levels were lower in the eight organs examined, which included the kidney and liver, after the injection of 1-OHP than following cisplatin administration. Plasma-decay profiles of three platinum species, that is, the unchanged species, filterable platinum, and total platinum, were examined. Plasma levels of the unchanged species and filterable platinum for 1-OHP declined more rapidly than those for cisplatin. The ratio of plasma filterable-to-total platinum indicated that the protein-binding ability of 1-OHP was greater than that of cisplatin. As for urinary excretion, amounts of the unchanged species and total platinum excreted during the 24 h period postinjection were 28% and 76% of the dose for 1-OHP and 23% and 57% of the dose for cisplatin, respectively. The renal clearance of both the unchanged species and filterable platinum in plasma for 1-OHP was about 2-fold that for cisplatin. 1-OHP is reported to be much less nephrotoxic than cisplatin. This may be due in part to its pharmacokinetic behavior or to pharmacokinetic differences resulting from chemical reactions that make 1-OHP less toxic than cisplatin.

Animals↗

PubMed1993

High resolution Tc-99m HMPAO SPECT in a patient with transient global amnesia.

This is a report of a patient who underwent high-resolution brain perfusion SPECT studies during and after an episode of transient global amnesia. During the attack, SPECT imaging showed increased perfusion in the left medial temporal region involving the amygdala and hippocampus. After recovery from amnesia, a follow-up SPECT examination showed slightly decreased perfusion in this region. These findings support the hypothesis that transient global amnesia is associated with transient hyperperfusion in the medial temporal brain structures, and confirm the utility of high-resolution SPECT imaging for the evaluation of the fine details of functional brain anatomy.

Adult↗

PubMed1993

Comparative SPECT study of stroke using Tc-99m ECD, I-123 IMP, and Tc-99m HMPAO.

Brain perfusion SPECT imaging using Tc-99m ethyl cysteinate dimer (ECD) was carried out in 12 patients with chronic cerebrovascular disease. The sensitivity of lesion detection and lesion-to-normal tissue contrast was compared with those of I-123 IMP and Tc-99m HMPAO. Eight patients underwent all three studies and the remaining four patients had Tc-99m ECD and I-123 IMP scans. The sensitivity of lesion detection and lesion contrast was analyzed quantitatively using an asymmetric index determined by the equation: 100 x [right - left[/(right + left). In the cerebral cortex, cerebellum, and white matter, I-123 IMP showed higher lesion sensitivity than Tc-99m ECD and Tc-99m HMPAO. In the striatum and thalamus, Tc-99m ECD and I-123 IMP showed higher lesion sensitivity than Tc-99m HMPAO. I-123 IMP showed the highest lesion contrast in cerebral cortex and cerebellum, whereas Tc-99m ECD showed the highest contrast in thalamus and striatum. In all regions, Tc-99m ECD showed higher lesion contrast than Tc-99m HMPAO. These results suggest regional variation in the sensitivity of lesion detection and lesion contrast of Tc-99m ECD compared to I-123 IMP, and the superiority of Tc-99m ECD to Tc-99m HMPAO.

Adult↗

PubMed1993

Differential regulation of glucose transport and transporters by glucose in vascular endothelial and smooth muscle cells.

Hyperglycemia has been implicated in the pathogenesis of both micro- and macrovascular complications in diabetes. Little is known, however, about glucose transporters and their regulation in the vascular system. In this study, the regulation of glucose transporters by glucose was examined in cultured BAECs and BSMCs, and in human arterial smooth muscle cells. Both BAECs and BSMCs transported glucose via the facilitated diffusion transport system. Glucose-transport activity in vascular smooth muscle cells was inversely and reversibly regulated by glucose. Exposure of BSMCs and HSMCs to high glucose decreased Vmax for 2DG and 3-O-MG uptake, whereas Km remained unchanged. The hexose-transport system of BAECs exhibited lower 2DG and 3-O-MG uptake compared with BSMCs and showed little or no adaptation to changes in ambient glucose. Northern blot analysis demonstrated that GLUT1 mRNA levels in BAECs and BSMCs were unaffected by the concentration of glucose in the medium. GLUT2-5 mRNA could not be detected by Northern blot analysis. GLUT1 protein, quantified by Western blot analysis, was more abundant in BSMCs than in BAECs and was decreased by approximately 50% when medium glucose was elevated from 1.2 to 22 mM for 24 h. The alterations in the level of GLUT1 protein correlated with the changes observed in transport activity. These observations suggest differential regulation of glucose transporter in response to glucose between smooth muscle and endothelial cells. The sites of autoregulation may involve translational control and/or the stability of the protein in the smooth muscle cells.(ABSTRACT TRUNCATED AT 250 WORDS)

3-O-Methylglucose↗

PubMed1993

[A case of coronary artery bypass grafting in a patient with active systemic lupus erythematosus].

A 59-year-old female was admitted to our hospital because of chest pain. Coronary angiography revealed severe obstruction of the left coronary artery. The findings of hematology and renal biopsy were interpreted as showing active systemic lupus erythematosus (SLE). Coronary artery bypass grafting was performed before steroid therapy because of worsening cardiac function due to myocardial ischemia. Postoperative course had been satisfactory immediately after operation, but the patient showed pulmonary infection about two months after operation and died three months after surgery. In open heart surgery for a patient with active SLE, special care must be taken to the prevention and treatment for infection.

Coronary Artery Bypass↗

PubMed1993

[One-staged operation for funnel chest, mitral regurgitation and annulo-aortic ectasia associated of Marfan's syndrome].

One-staged operation was successfully performed in a 23-year-old female with funnel chest, mitral regurgitation and annulo aortic ectasia secondary to Marfan's syndrome. A midline skin incision was made and the sternum and costal cartilages were mobilized for sternal turnover with rectus muscles pedicle. This procedure offered an excellent operative field, even though the heart and aneurysmal ascending aorta were displaced into the left hemithorax. The combined superior-transseptal approach to the left atrium was used to perform mitral valve replacement. This approach also provided an excellent exposure of the mitral valve. Cabrol's operation was done for annulo aortic ectasia. Our concepts for the operation of open heart surgery complicated with severe funnel chest were discussed.

Adult↗

PubMed1992

Expression of human soluble tissue factor in yeast and enzymatic properties of its complex with factor VIIa.

The extracellular domain of human tissue factor (TF, amino acids 1-217) was expressed in Saccharomyces cerevisiae, using the inducible yeast acid phosphatase promoter and the yeast invertase signal sequence to direct its secretion into the culture broth. Two active soluble forms sTF alpha (high molecular weight form) and sTF beta (low molecular weight form) were purified, the yield being approximately 10 and 1 mg/liter of culture supernatant, respectively. sTF alpha had an apparent molecular mass of 150 kDa on SDS-polyacrylamide gel electrophoresis and contained more than 200 residues of mannose/mol of protein. sTF beta had an apparent molecular mass of 37 kDa and contained 22 residues of mannose/mol of protein. N-Glycosidase F treatments of both rTFs reduced the apparent molecular mass to 35 kDa. The amino-terminal sequences and amino acid compositions of sTF alpha and sTF beta were consistent with those deduced from the cDNA sequence, thereby indicating that the difference in molecular mass is caused by heterogeneity of oligosaccharide structures. Of these recombinant TFs, sTF beta enhanced factor VIIa-amidolytic activity 40-fold toward the chromogenic substrate and 147-fold toward the fluorogenic substrate, affecting mainly the kcat value. The enhancement was comparable with that of TF purified from human placenta. The TF-mediated enhancement of factor VIIa-amidolytic activity was inhibited by heparin-activated antithrombin III, forming a high molecular weight complex. As treatment of sTF beta with denaturants such as guanidine hydrochloride or urea led to a biphasic loss of the activity, the extracellular domain of TF probably consists of two discrete domains. This expression system provides a significant amount of the extracellular domain of TF so that studies of interactions with factor VII are feasible.

Amino Acid Sequence↗

PubMed1992

Tissue factor potentiates the factor VIIa-catalyzed hydrolysis of an ester substrate.

We designed a simple and sensitive method to assay the activity of the factor VIIa-tissue factor complex, using as a substrate N alpha-benzyloxycarbonyl-L-arginine p-nitrobenzyl ester (Z-Arg-ONb) (Zur, M., and Nemerson, Y. (1978) J. Biol. Chem. 253, 2203-2209). The principle was to measure the amount of p-nitrobenzyl alcohol released during ester hydrolysis using reversed-phase high performance liquid chromatography. Z-Arg-ONb had a broad specificity for plasma serine proteases and factor IXa. Using this method, we examined the effect of tissue factor on the esterase activity of factor VIIa under various conditions. We found that tissue factor greatly potentiates the factor VIIa-catalyzed hydrolysis of Z-Arg-ONb. Phospholipids were not required for the factor VIIa-catalyzed hydrolysis of Z-Arg-ONb, even in the presence of tissue factor. The Km value of factor VIIa alone toward the ester substrate was six times higher than that of a VIIa-tissue factor complex (3.2 versus 0.54 mM), whereas the kcat value was 12 times lower than that of the VIIa-tissue factor complex (14.3 versus 173 s-1). Thus, tissue factor apparently affects the catalytic site of factor VIIa and enhances hydrolysis of the ester substrate. This enhancing effect of tissue factor disappeared on removal of the gamma-carboxyglutamic acid domain from factor VIIa, whereas the esterase activity in the absence of tissue factor was not affected by this modification. The gamma-carboxyglutamic acid domain is probably required as a potent determinant for interactions with tissue factor, even in the absence of phospholipids in the reaction mixture.

Amino Acid Sequence↗

PubMed1992

Both the anaerobic pathway and aerobic desaturation are involved in the synthesis of unsaturated fatty acids in Vibrio sp. strain ABE-1.

Vibrio sp. strain ABE-1 is a unique marine bacterium in terms of its ability to synthesize delta 9-trans-hexadecenoic acid and delta 7-cis-tetradecenoic acid (14:1(7c); Okuyama, H., Sasaki, S., Higashi, S. and Murata, N. (1990) J. Bacteriol. 172, 3515-3518). The present study, involving labeling with [1-14C]acetate, demonstrated that 14:1 is synthesized by the anaerobic pathway. When cells of this bacterium were grown in the presence of [1-14C]myristic acid (14:0), this compound was converted to palmitic (16:0) and hexadecenoic (16:1) acids but not to 14:1, under aerobic conditions. These results suggest that the incorporated 14:0 was elongated to 16:0 and then converted to 16:1 by the aerobic desaturation of 16:0. It appears that the anaerobic pathway and aerobic desaturation are both involved in the synthesis of unsaturated fatty acids during aerobic growth of Vibrio sp. strain ABE-1.

Acetates↗

PubMed1992

Hemifacial spasm associated with a cerebellopontine angle arachnoid cyst in a young adult.

There are no reported cases of hemifacial spasm associated with an arachnoid cyst in the literature. We report the first case of hemifacial spasm with an ipsilateral cerebellopontine angle arachnoid cyst in a 25-year-old man. The patient underwent evacuation of the arachnoid cyst by a partial membranectomy without any beneficial effect, and finally got rid of the hemifacial spasm by reexploration and microvascular decompression of the facial nerve. The operative findings and results revealed that the cyst produced deviation of the ipsilateral posterior inferior cerebellar artery, which was secondarily in contact with the root exit zone of the facial nerve.

Adult↗

PubMed1992

Laparoscopic varicocelectomy: a simple technique for clip ligation of the spermatic vessels.

Less invasive laparoscopic surgery is replacing the conventional open operation for the treatment of several conditions. We performed laparoscopic clamping of the internal spermatic vessels in 12 subfertile patients to treat varicocele of the testis. Seven operations were performed with the patient under general anesthesia, whereas a local anesthetic was used in the 5 most recent patients. The internal spermatic vessels were successfully clipped in all 12 patients. Postoperative physical examination with a Doppler stethoscope showed that the venous reflux had disappeared in all patients. Semen quality was improved in 7 patients with a followup of 3 to 10 months. Neither hydrocele nor testicular atrophy was observed postoperatively. Laparoscopic varicocelectomy was effective and minimally invasive, especially when performed with the patient under local anesthesia.

Adult↗

PubMed1992

Cerebral vasospasm with elevated creatine phosphokinase following surgery of unruptured arteriovenous malformation.

Delayed cerebral vasospasm associated with marked elevation of serum creatine phosphokinase (CPK) is reported. A 21-year-old man with unruptured arteriovenous malformation (AVM) in the left temporal lobe developed postoperative symptomatic vasospasm lasting for 2 weeks. A postoperative computerized tomography scan showed intraventricular hematoma without subarachnoid hemorrhage in the basal cistern. On day 5 after surgery, the patient developed motor aphasia due to marked vasospasm around the bifurcation of internal carotid artery. On day 7 and 8, serum CPK was elevated as high as 1175 and 1376 IU/l, respectively. On day 35 when he had completely recovered from cerebral vasospasm both clinically and angiographically, the level of CPK was normalized. The causative factors of symptomatic cerebral vasospasm following surgery of unruptured AVM associated with CPK elevation are discussed.

Adult↗

PubMed1992

32P-postlabeling analysis of DNA adducts in rats during estrogen-induced hepatocarcinogenesis and effect of tamoxifen on DNA adduct level.

DNA adduct formation in the liver, pancreas, kidneys and uterus in ethynylestradiol (EE)-induced carcinogenesis and the effect of tamoxifen (TAM) on DNA adduct formation were evaluated in female Wistar JCL rats using the 32P-postlabeling method. Hyperplastic nodules were noted in the liver of all rats 4 months after the first oral administration of 0.075 mg of EE, and hepatocellular carcinoma was detected in 8.1% of rats treated with EE for 12 months. DNA adducts increased in the liver for 4 months, reaching a level of 7.3 adducts/10(7) nucleotides and decreasing thereafter. Formation of DNA adducts was also noted in the pancreas and kidney, but the adduct levels were lower than those in the liver. TAM inhibited estrogen receptors (ER) in liver tissues and completely suppressed the development of hyperplastic nodules or hepatocellular carcinoma but did not affect DNA adduct formation in the liver. In this model, therefore, EE is considered to cause mutations of hepatocytes due to DNA adduct formation without mediation by ER and to induce initiated cells to develop into hepatocellular carcinoma in the presence of ER-mediated hormonal activities.

Animals↗