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Biomedical subjects

Y Koga

Publications and source records attributed to Y Koga.

At least 325 records · Page 18Linked to original sources
PubMed1992

[Assessment of fetal lung maturity using newly developed immunological measurement of fetal pulmonary surfactant apoprotein-A in amniotic fluid].

The level of immunoreactive lung surfactant apoprotein A (SP-A) was determined with a newly developed one-step ELISA kit (TDR-20) in 217 samples obtained by transabdominal or transvaginal amniocentesis from 217 pregnant women with high risk pregnancy. The lecithin/sphingomyelin ratio (L/S ratio) by two-dimensional thin layer chromatography, disaturated phosphatidylcholine (DSPC) values, shake test and the stable microbubble method were done simultaneously to compare diagnostic reliability in estimating fetal lung maturity. Amniotic fluid SP-A levels increased with advancing gestational age and correlated well with the values obtained by the other methods. When the cut-off SP-A value for the assessment of lung maturity was set at 1,700ng/ml in the amniotic fluid obtained within 24h before delivery, the true-negative rate for RDS was 71% and the true-positive rate for non-RDS was 83%. The sensitivity, specificity and accuracy were 100%, 83% and 88%, respectively. These results are comparable with those for the L/S ratio, DSPC determination and the stable microbubble method, and were slightly better than those for the shake test. In conclusion, this newly developed ELISA kit for the measurement of amniotic fluid SP-A is more effective than other methods currently available for the evaluation of fetal lung maturity, when it is considered that it requires only 0.2ml of amniotic fluid and provides results in only 2h without technical difficulties.

Amniotic Fluid↗
PubMed1992

[Use of omeprazole for premedication].

Omeprazole, a proton pump inhibitor was used for premedication for general anesthesia, and its effects on gastric secretion and serum gastrin level were investigated in 60 patients. The patients were divided into the following 4 groups and each group received one of the following medications; (I) a tablet of omeprazole 20 mg before sleep at the night before the surgery, (II) a tablet 2 hours before the induction of anesthesia, (III) one on the night before and another tablet 2 hours before the induction, or (0) no tablet. In the patients who received any dose of the drug, the volume of gastric juice at the beginning of the surgery was significantly less than that in those who received no drug (P less than 0.05). Gastric pH showed a tendency to increase depending on the dose of omeprazole (0 less than I less than II less than III), but it was not significant. No significant change in serum gastrin level was observed in this study. A 20 mg omeprazole tablet may not be adequate as the premedication for general anesthesia.

Administration, Oral↗
PubMed1992

[The effect of preoperative oral administration of ranitidine on pH and volume of gastric juice].

The effect of ranitidine, administrated 2 or 4 hours prior to induction of anesthesia, on volume and pH of gastric juice was investigated in patients undergoing elective surgery. Three-hundred mg of ranitidine was administrated orally in 54 patients 2 hours prior to anesthesia and in 50 patients 4 hours prior to anesthesia. The volume and pH of gastric juice were measured immediately after induction of anesthesia. In more than 90% of patients of both groups, volume of gastric juice was smaller than 25 ml and its pH was more than 2.5. Ranitidine 450 mg was administrated orally in 7 patients, and its plasma concentration was measured 2, 4 and 6 hours after administration. In one patient, volume of gastric juice was larger than 25 ml and its pH was less than 2.5. Ranitidine concentration in this patient was below the effective level 2 hours after administration and it was above the level after 4 hours. We concluded that oral administration of ranitidine 300 mg, 4 hours preoperatively, could be more effective to prevent aspiration pneumonitis than when it is given 2 hours preoperatively.

Administration, Oral↗
PubMed1992

An inactive cathepsin B-like enzyme and cysteine proteinase inhibitors in colon cancer ascites.

The ascitic fluid of a patient with colon cancer was found to contain an inactive cathepsin B-like enzyme. The inactive enzyme with a molecular weight of 40 kDa was converted by pepsin treatment into an active form with a molecular weight of 28 kDa as revealed by Sephadex G-75 gel chromatography. The inactive cathepsin B-like enzyme was considered to represent a precursor form and not an enzyme-inhibitor complex. The activated cathepsin B-like enzyme resembled human liver cathepsin B in its enzymatic characteristics. Cysteine proteinase inhibitor activity was also detected in the same ascitic fluid, and it was separated into two main forms by Sephadex G-75 gel chromatography. The high molecular weight inhibitor fractions reacted with antiserum against alpha-CPI and the low molecular weight fractions reacted with antiserum against cystatin B.

Ascites↗
PubMed1992

[Ergometric and pathologic study of a family with complex I deficiency].

We studied a family with a myopathic form of complex I deficiency with regard to the clinical symptoms, usefulness of the exercise tolerance test with an ergometer for screening of mitochondrial abnormalities, pathological findings in biopsied muscles and genetics. In this family, none of the members had disorders of the central nervous system, such as convulsions, mental deterioration or stroke-like episodes. In the two affected generations, three mothers and three children had mitochondrial abnormalities. Two children were diagnosed as having complex I deficiency. One of them, an 8-year-old girl with normal psychomotor development during infancy, began to experience easy fatigability at about 3 years of age. At the age of 5 years, she experienced respiratory distress and became unconscious. Thereafter, she had similar episodic respiratory problems with lactic acidosis. Ragged-red fibers and respiratory chain enzyme defects were detected in the biopsied muscle. Another child, a 15-year-old boy with easy fatigability but no muscle weakness, had normal respiratory chain enzyme activities and a normal oxysogram: oxygen consumption showed a normal responses when malate and pyruvate were added as substrates for the isolated mitochondria. His muscle pathology revealed rare ragged-red fibers and abnormal subsarcolemmal mitochondrial aggregation. An investigation with an ergometer showed elevated serum lactate and pyruvate levels. Only one mother had muscle weakness and hyper-lactic acidemia. The other two mothers had no muscle symptoms, but abnormal results were obtained with the ergometer.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

Decreased perfusion in myocardial region of normal donor artery secondary to collateral development. Stress 201Tl myocardial emission CT performed in patients with single vessel exertional angina having collaterals.

Thirty-one patients suffering from single vessel exertional angina with collaterals (Group A) were evaluated by stress 201T1 myocardial emission CT (Tl-SPECT) with 16 controls of severely stenotic single vessel exertional angina without collaterals (Group B). Group A included 21 patients (68%) who showed an extensive perfusion defect in double artery myocardial regions, including the normal donor artery myocardial region (DMR). However, there were no such cases in Group B, giving a significant difference between these 2 groups (p less than 0.001). Four patients in Group A, having a perfusion defect both in DMR and in the collateral dependent myocardial region (CMR) underwent a successful percutaneous transluminal coronary angioplasty (PTCA) with disappearance of collaterals. Tl-SPECT findings after PTCA showed no perfusion defect either in CMR or in DMR. This has been explained on the basis that the coronary collaterals stole blood and produced perfusion defect in DMR.

Aged↗
PubMed1992

Continuous monitoring of blood oxygen saturation of internal jugular vein as a useful indicator for selective cerebral perfusion during aortic arch replacement.

We continuously monitored blood oxygen saturation in the internal jugular vein during selective cerebral perfusion for aortic arch operations and evaluated its efficacy as an indicator of cerebral oxygen metabolism. The selective cerebral perfusion method was applied in 11 patients who underwent operations for aortic arch replacement. Blood oxygen saturation in the internal jugular vein was continuously monitored at the bulbus jugularis with a fiberoptic catheter during the operation. Perfusion flow of 500 ml/min was continued for 134.7 +/- 14.9 minutes under moderate hypothermia at 25 degrees C, and bilateral temporal arterial pressure was 40 to 60 mm Hg. Blood gas data were used to estimate oxygen consumption, oxygen extraction ratio, and lactate uptake in the cerebrum. No patients had postoperative cerebral complications. Cerebral oxygen consumption was 2.93 +/- 0.4 ml/min/100 gm under general anesthesia at 36 degrees C. While selective cerebral perfusion at 25 degrees C decreased consumption to 0.92 +/- 0.39 ml/min/100 gm, it fell to about 30% of its former value. Blood oxygen tension in the internal jugular vein showed no significant correlation with rectal temperature. Selective cerebral perfusion did not significantly affect cerebral lactate uptake. In contrast, blood oxygen saturation in the internal jugular vein was significantly affected by temperature and cerebral flow during selective cerebral perfusion, and blood oxygen saturation in the internal jugular vein correlated closely with cerebral oxygen extraction ratio (r = 0.91). Cerebral oxygen metabolism was thus well maintained, and continuous monitoring of blood oxygen saturation in the internal jugular vein was found to serve as a useful indicator under selective cerebral perfusion during operations for aortic arch replacement.

Adult↗
PubMed1991

Vitamin E deficiency has a pathological role in myocytolysis in cardiomyopathic Syrian hamster (BIO14.6).

This study revealed the occurrence of vitamin E deficiency in the myocardium of 60-day-old Syrian cardiomyopathic hamsters (BIO14.6), and that this deficiency might be related to the increase in lipid peroxide. Vitamin E administration for ten days effectively restored creatininekinase activity and decreased the lipid peroxide content in the myocardium, returning these to normal control levels (F1b). These results indicate that vitamin E deficiency, possibly combined with oxidative stress in the early cardiomyopathic stage plays an important role in initiating the pathogenesis of myocardial lesions.

Animals↗
PubMed1991

Differential expression of two lck transcripts directed from the distinct promoters in HTLV-I+ and HTLV-I- T-cells.

The lck gene encodes a lymphocyte-specific tyrosine protein kinase, p56lck, the expression of which is almost exclusive in T-cells. The expression of lck in human T-cell leukemia virus type I (HTLV-I)-transformed T-cell lines is closely associated with interleukin-2 (IL-2) dependence for their growth. That is, IL-2-dependent HTLV-I-transformed cell lines contain the lck message abundantly as HTLV-I-negative T-cell lines, whereas IL-2-independent HTLV-I-transformed cell lines express either no or little lck mRNA, although they are derived from T-cells. The lck gene contains 2 distinct promoters which direct 2 types of lck transcript with different 5' untranslated regions. In this study, we show that HTLV-I-transformed IL-2-dependent T-cell lines contain the upstream promoter-initiated lck transcript exclusively, in contrast to HTLV-I-negative transformed T-cell lines which express the down-stream promoter- as well as the upstream promoter-initiated lck transcript. In addition, lck mRNA disappears transiently in IL-2-dependent HTLV-I-transformed T-cell lines after stimulation for T-cell activation, which is also observed in peripheral blood T lymphocytes. These results indicate that the disappearance of lck mRNA in HTLV-I-transformed, IL-2-independent cell lines is caused by a mechanism which down-regulates the upstream promoter-initiated lck transcript and this IL-2-independent state may represent a further "activated" condition of the IL-2-dependent state by the stimulation which mediates T-cell activation.

Blotting, Northern↗
PubMed1991

Hydroxyarchaetidylserine and hydroxyarchaetidyl-myo-inositol in Methanosarcina barkeri: polar lipids with a new ether core portion.

Lipids of the methanogenic archaebacterium, Methanosarcina barkeri were analyzed. The lipid content was 5.4% of dry cell and polar lipids comprised 87% of the total lipid. Polar lipids were separated into 14 spots by two-dimensional thin-layer chromatography. These were six phospholipids, seven aminophospholipids and one glycolipid, of which two phospholipids and two aminophospholipids were major constituents. After removal of polar head groups from total lipids, two kinds of glycerol diether core lipids were found. One was 2,3-di-O-phytanyl-sn-glycerol (archaeol) and the other 2-O-(3'-hydroxy-3', 7', 11', 15'-tetramethyl)hexadecyl-3-O-phytanyl-sn- glycerol (hydroxyarchaeol). Those structures were identified on the basis of chemical analysis, fast atom bombardment spectrometry, gas-liquid chromatography-mass spectrometry and 1H- and 13C-NMR spectrometry. The latter was a new core lipid which was different from hydroxyarchaeol of Methanothrix concilii. The hydroxyarchaeol core lipid comprised 60% of polar lipid in M. barkeri. The structures of core lipids are quite different from those previously reported by De Rosa et al. (Biochim, Biophys. Acta (1986) 875, 487-492) concerning M. barkeri lipids. The structures of two major polar lipids, both of which had hydroxyarchaeol as core proteins, were elucidated. These lipids were 2-O-(3'-hydroxy)phytanyl-3-O-phytanyl-sn-glycero-1-phosphoserine (hydroxyarchaetidylserine) and 2-O-(3'-hydroxy)phytanyl-3-O-phytanyl-sn- glycerol-phospho-myo-inositol (hydroxyarchaetidyl-myo-inositol). Archaetidylserine and archaetidylinositol, which had the usual archaeol core portion, were also present as minor polar lipids.

Archaea↗
PubMed1991

Prognostic factors in the treatment of hepatocellular carcinoma with transcatheter arterial embolization and arterial infusion.

From January 1986 to December 1988, a prospective trial of transcatheter arterial treatment was carried out for hepatocellular carcinoma (HCC). Two hundred seventy-five patients were included. Okuda's staging system was employed. Patients with Stage I and II HCC were treated by transcatheter arterial embolization (TAE) with a gelatin sponge containing an anti-cancer agent (protocol 1a); a gelatin sponge and iodized oil mixed with an anti-cancer agent (protocol 1b); or iodized oil mixed with an anti-cancer agent (protocol 2). Patients with Stage III HCC were treated with iodized oil with anti-cancer agent (protocol 2). As an exception, patients with an unsuccessful superselective catheterization into the proper hepatic artery by Seldinger technique or obstruction of the main trunk of the portal vein were treated with percutaneous transcatheter arterial infusion into the common hepatic artery regardless of stage (protocol 3). Tumor type and extension, area of tumor involvement, portal vein involvement, method of treatment, and presence of ascites and icterus were found to be the significant factors for an initial response to therapy. Treatment method was the most important factor. Respective survival rates at 1 and 2 years were 70.9% and 55.3% for protocol 1a; 62.3% and 43.8% for protocol 1b; 37.8% and 18.3% for protocol 2; and 16.5% and 0% for protocol 3. Many factors proved to significantly influenced prognosis; however, tumor type had the most important prognostic significance followed by AFP value, ascites, treatment protocol, and area of tumor involvement.

Adult↗
PubMed1991

Abnormal development of cardiovascular systems in rat embryos treated with bisdiamine.

Administration of N,N'-bis(dichloroacetyl)-1,8-octamethylenediamine, bisdiamine, in pregnant Donryu rats on day 10 of gestation induces a high incidence of cardiovascular anomalies in fetuses. Bisdiamine administration induced aplasia of the sixth aortic arch artery, with both the right and left primitive pulmonary arteries being directly linked to the truncus, and resulting in four types of malformation of pulmonary arteries (PAs). When two primitive PAs shared a single root, the consequence was either pulmonary trunk hypoplasia, as is seen in tetralogy of Fallot, or type I persistent truncus arteriosus (PTA) as classified by Collet and Edwards. When root portions of two PAs did not fuse, either type II or type III PTA resulted. In controls, the right dorsal aorta (DA) between the right seventh intersegmental artery (IA) and the site where both DAs fuse degenerated and the left aortic arch (AA) and the right subclavian artery (SA) were formed. Bisdiamine administration induced two additional types of vascular anomalies. In one of these, the right DA between the right 4AA and the right 7IA degenerated and a left AA accompanied by an aberrant right SA resulted. In the other type, the left DA between the left 4AA and the left 7IA degenerated and a right AA accompanied by an aberrant left SA resulted. These results indicate that administration of bisdiamine induces malformation in the great blood vessels by disturbing persistency and degeneration of aortic arch arteries and DAs.

Abnormalities, Drug-Induced↗
PubMed1991

Mitochondrial encephalomyopathies and cytochrome c oxidase deficiency: muscle culture study.

The populations of cytochrome c oxidase (CCO)-positive and -negative mitochondria were analyzed in the elongated cells containing occasional multiple nuclei (myotubes) in primary muscle cultures derived from patients with various forms of mitochondrial encephalomyopathies with CCO deficiency. Even in control muscle cultures, CCO-positive (79.7%) and -negative (20.3%) mitochondria were distributed randomly, showing intracellular mosaicism. All mitochondria in all muscle cultures from two patients with clinical characteristics of Leigh's disease exhibited faint to negative CCO activity. In these patients no enzyme activity could be detected in any tissue including intrafusal fibers and fibroblasts in muscle biopsies. In patients with the fatal infantile and the encephalomyopathic forms of CCO deficiency, and myoclonic epilepsy with ragged-red fibers, two different types of myotubes containing mostly CCO-positive mitochondria and only negative mitochondria, respectively, representing intercellular mosaicism, were demonstrated. The intercellular mosaicism in biopsied and cultured muscles in the case of CCO deficiency supports the contention that both CCO-positive and -negative mitochondria coexist in the early myogenic cell and are later randomly segregated during cell division (mitotic segregation), forming two different cells.

Adolescent↗
PubMed1991

Thermotolerance in regional hyperthermia in vivo--an experimental study using the MH134 tumor.

In the clinical application of hyperthermia, determining the thermotolerance that influences the anti-tumor effect is an important problem. The purpose of this study was to investigate the methods of induction and disappearance of thermotolerance in vivo. After transplanting MH134 cancer cells into the paws of C3H mice, local hyperthermia with warm water was administered, and the movement of thermotolerance in vivo studied in terms of the heating intervals and tumor growth times. When the first heating was applied on the 8th day after transplantation, thermotolerance appeared within 1 hour, increasing gradually to reach a maximum at 18 hours, after which it decreased gradually and disappeared after 48 hours. When the first heating was applied on the 13th day after transplantation, which fell during the rapid tumor proliferation period, the movement of thermotolerance presented a similar pattern of appearance and disappearance. The results of this study made it clear that there was no difference in the movement of thermotolerance between the two periods even though each had a different rate of tumor proliferation.

Animals↗
PubMed1991

Usefulness of reinjection image for evaluating viable myocardium in the infarcted zone on exercise thallium-201 SPECT.

Reinjection images were obtained in 23 patients with myocardial infarction by the additional injection of 37 MBq of thallium-201 after obtaining 4 hour delayed images on exercise thallium-201 SPECT (TSPECT). A redistribution index (RI) was derived of the changes in perfusion defects between immediate and 4 hour delayed images as well as immediate and reinjection images on polar bull's eye maps. The RI of reinjection images (46 +/- 27%) was significantly greater than that of 4 hour delayed images (26 +/- 26%) in patients with myocardial infarction (p less than 0.01). Significant redistribution after reinjection occurred in 4 of 9 patients (44%) without significant redistribution on 4 hour delayed images. Improvement in redistribution on reinjection images correlated significantly to the small extent of coronary artery disease and collateral development. The appearance of redistribution from 4 hour delayed imaging to reinjection imaging also might reflect the function of collateral development in the resting state in patients without significant redistribution on 4 hour delayed images. It has been demonstrated that underestimated viable myocardium on 4 hour delayed images in the infarcted zone can be better assessed on reinjection images. This reinjection technique is recommended in patients with no or partial redistribution on 4 hour delayed images.

Adult↗
PubMed1991

The effects of a thromboxane A2 receptor antagonist on neurologic recovery after 15 min complete global brain ischemia in dogs.

The effects of a thromboxane A(2) receptor antagonist (anti-TXA(2); ONO-3708) on the neurologic recovery after 15 min complete cerebral ischemia were investigated in dogs. Complete cerebral ischemia was achieved by occlusion of the trunk of the aorta, the superior and the inferior caval vein. Seventeen dogs were divided into 2 groups; 1) control group (no drug, n = 9), 2) Anti-TXA(2) group (anti-TXA(2) 200 mcg.kg(-1) in iv bolus soon after recirculation followed by continuous infusion at a rate of 10 mcg.kg(-1).min(-1) for 3 days, n = 8). EEG, auditory brainstem response (ABR), middle latency response (MLR), and somatosensory evoked potential (SEP) recordings were obtained before ischemia, 120 min after re-circulation and on the 7th day after ischemia. The neurologic recovery score (NRS) were determined on the 3rd and the 7th day. Impaired EEG score was significantly higher in the anti-TXA(2) group on 7th day after ischemia ( P < 0.05). Anti-TXA(2) increased the reappearance rates of the ABR-Vth ( P < 0.05) and the SEP-N(3) waves ( P < 0.01) at 120 min after ischemia. The survival rate tended to be higher in the anti-TXA(2) group. However, NRS did not significantly differ in the groups.

Journal Article↗
PubMed1991

Effect of hypothermic ischemia and reperfusion on calcium transport by myocardial sarcolemma and sarcoplasmic reticulum.

The effects of hypothermic ischemia and reperfusion on sarcolemma and sarcoplasmic reticulum Ca2+ transport were studied in vesicles isolated from rabbit hearts. Hypothermic global ischemia was produced by immersing hearts in saline at 4 degrees C for 3 h. Following hypothermic ischemia, reperfusion was carried out for 40 min using a Langendorff perfusion system for the working heart. Na+,K(+)-ATPase activity of sarcolemmal vesicles (SL), was not depressed by hypothermic ischemia nor by ischemia and reperfusion. The initial rate of Na(+)-Ca2+ exchange in SL vesicles was not depressed, but the maximum amount of Ca2+ uptake was increased both after hypothermic ischemia and after reperfusion. Ca2+ uptake activity of sarcoplasmic reticulum vesicles (SR) isolated from hearts subjected to hypothermic ischemia was slightly lower than that of control, and was further reduced following reperfusion. Ca(2+)-ATPase activity of SR was unaffected by hypothermic ischemia, while it was markedly lowered after reperfusion. Although the phosphoenzyme level in SR vesicles was slightly decreased, the turnover rate was reduced after reperfusion. Reperfusion injury thus took place mainly in SR while SL appeared to be tolerant to ischemia and reperfusion.

Adenosine Triphosphatases↗