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Biomedical subjects

S Koike

Publications and source records attributed to S Koike.

At least 145 records · Page 8Linked to original sources
PubMed1992

[Experience of intravascular ultrasound imaging on a stenosed saphenous vein graft].

A 73-year-old man underwent coronary-artery bypass grafting surgery on #4 PD and #7 with saphenous vein graft. Coronary arteriography and graft visualization performed on the 28th postoperative day revealed 75% concentric stenosis in the middle of the #4 PD graft. Before and after PTCA to the graft, examination by intravascular ultrasound imaging was performed and revealed that the stenosis was caused by fibrotic atheroma or thrombus. Intravascular ultrasound imaging appears to be useful in the field of cardiac surgery. It can be used in the follow-up of bypass grafts and also the detection of the entry site in dissecting aortic aneurysms. A brief review of the literature is given.

Aged↗
PubMed1992

Nonlinear survival curves for cells of solid tumors after large doses of fast neutrons and gamma rays.

We have previously proposed that survival curves for cells of murine NFSa fibrosarcomas after exposure to fast neutrons might demonstrate curvature when the neutron doses reach a level high enough to cure the fibrosarcomas. We report here that this is the case. Murine NFSa fibrosarcomas growing in the hind legs of syngeneic mice were exposed to either gamma rays or fast neutrons. The tumors were removed and retransplanted into fresh recipients to obtain 50% tumor cell doses, from which the dose-cell survival relationship was constructed. Survival curves showed continuous bending down to 10(-7), and were well fitted using the linear-quadratic model. The alpha and beta values for neutrons were larger than those for gamma rays. When the surviving fractions at experimental TCD50 doses were calculated using these values, comparable figures were obtained for neutrons and gamma rays. The RBEs for neutrons were comparable for the TCD50 and TD50 assays. Neutron RBE was independent of dose within a range of 5-28 Gy. The capacity of the tumors to repair the damage caused by large doses of neutrons was identical to that for small doses of neutrons, indicating that cells retained the capacity to repair neutron damage irrespective of the size of the dose.

Animals↗
PubMed1991

Functional domains of the poliovirus receptor.

A number of mutant cDNAs of the human poliovirus receptor were constructed to identify essential regions of the molecule as the receptor. All mutant cDNAs carrying the sequence coding for the entire N-terminal immunoglobulin-like domain (domain I) confer permissiveness for poliovirus to mouse L cells, but a mutant cDNA lacking the sequence for domain I does not. The transformants permissive for poliovirus were able to bind the virus and were also recognized by monoclonal antibody D171, which competes with poliovirus for the cellular receptor. These results strongly suggest that the poliovirus binding site resides in domain I of the receptor. Mutant cDNAs for the sequence encoding the intracellular peptide were also constructed and expressed in mouse L cells. Susceptibility of these cells to poliovirus revealed that the entire putative cytoplasmic domain is not essential for virus infection. Thus, the cytoplasmic domain of the molecule appears not to play a role in the penetration of poliovirus.

Animals↗
PubMed1991

Transgenic mice susceptible to poliovirus.

Poliovirus-sensitive transgenic mice were produced by introducing the human gene encoding cellular receptors for poliovirus into the mouse genome. Expression of the receptor mRNAs in tissues of the transgenic mice was analyzed by using RNA blot hybridization and the polymerase chain reaction. The human gene is expressed in many tissues of the transgenic mice just as in tissues of humans. The transgenic mice are susceptible to all three poliovirus serotypes, and the mice inoculated with poliovirus show clinical symptoms similar to those observed in humans and monkeys. Rabbit antipoliovirus serum detects the antigens mainly in motor neurons in the anterior horn of the spinal cord and in nerve cells in the medulla oblongata and pons of the paralyzed transgenic mice. Therefore, cell types sensitive to poliovirus in the central nervous system of the transgenic mice appear to be identical to those of humans and monkeys. Furthermore, many more doses of oral poliovirus vaccine strains than of the virulent strains are required to cause paralysis in the transgenic mice. This may reflect the observation that the virulent strain multiplies more efficiently in the central nervous system than the attenuated strain. Thus, the transgenic mice may become an excellent new animal model to study molecular mechanisms of pathogenesis of poliovirus and to assess oral poliovirus vaccines.

Animals↗
PubMed1991

The N-terminal transactivation domain of rat estrogen receptor is localized in a hydrophobic domain of eighty amino acids.

In order to determine the transactivation domain(s) of the rat estrogen receptor (rat ER), we made a number of rat ER deletion mutants and transfected the mutant plasmids into COS7 cells together with an estrogen-responsive reporter plasmid, ERE-tk(197)-CAT, which contained the estrogen response element of Xenopus vitellogenin A2 gene. We have identified and localized the N-terminal transactivation domain of the rat ER to a hydrophobic region extending from Ala 59 to Glu 140.

Animals↗
PubMed1991

Infective endocarditis causing acute myocardial infarction by compression of the proximal left coronary artery due to a mycotic aneurysm of the sinus of Valsalva.

An extremely unusual case of myocardial infarction associated with infective endocarditis (IE) is described. A 38-year old male with a high fever was transferred to our hospital for further treatment of IE. Two-dimensional echocardiogram showed a large mycotic aneurysm of the sinus of Valsalva in contact with neighbouring structures. The patient had a rapid recovery within several days after administration of antibiotic agents. However, he then developed abrupt onset of severe precordial pain. From the echocardiogram images and biochemical evaluation he was diagnosed as having an acute subendocardial infarction. Serial echocardiograms revealed expansion of the aneurysm, extending from the myocardium of the anterolateral free wall to the lower margin of the proximal left coronary artery. The cause of acute myocardial infarction was thought to be incomplete occlusion of the coronary artery through compression by the enlarging mycotic aneurysm of the sinus of Valsalva. Urgent surgery confirmed compression of the left coronary artery by the large mycotic aneurysm as the cause of acute myocardial infarction.

Adult↗
PubMed1991

[Operative management of the calcified patent ductus arteriosus in the elderly].

Two cases of the calcified PDA were experienced in subjects aged more than 50 years. A 63-year-old woman was successfully operated upon. A Fogarty's balloon catheter was wedged into the PDA through the ductus after a pulmonary arteriotomy under cardiopulmonary (CP) bypass. A 57-year-old woman was safely operated. PDA was repaired under partial CP bypass with Bio-pump. Postoperative courses of these cases were uneventful. Brief review of surgical treatment for PDA was given.

Calcinosis↗
PubMed1991

[Patients resuscitated from cardiopulmonary arrest: clinical and electrophysiologic study].

Clinical and electrophysiologic studies (EPS) were carried out in 12 patients who were resuscitated from cardiopulmonary arrest (CPA). They were 8 males and 4 females, ranging from 33 to 73 years of age with a mean of 55 years. Underlying diseases included old myocardial infarction (OMI) with aneurysm (An) in 6 patients, variant angina, arrhythmogenic right ventricular dysplasia, Romano-Ward syndrome, complete atrioventricular block in one each, and diseases of unknown etiology in 2. Ergonovine-provocative coronary angiography (CAG) was performed in 3 patients, and EPS including ventricular tachycardia study was performed in 7. Coronary artery spasm was induced in one patient during CAG; sustained monomorphic ventricular tachycardia in 4 patients; and repetitive ventricular response in 2 of 7 patients examined by EPS. The causes of cardiopulmonary arrest were clearly demonstrated by the above-described examinations in 3 cases of clinically unidentified etiology. Drug therapy was performed in 6 patients during EPS (1.7 drugs/case), which was effective in one, ineffective in 3, and undetermined in 2. Of 2 patients whose surgical treatment was unsuccessful, atrial pacing with propranolol administration was used in a patient with Romano-Ward syndrome. The remaining patients were followed up medically. Cardiopulmonary arrest recurred in 3 patients and resuscitation was not successful in any of them; one with OMI and the other 2 with idiopathic ventricular fibrillation who refused EPS and died suddenly 10 months and 12 months after their initial resuscitation. Cardiac arrest did not recur in any of those who underwent complete examinations and were treated with medications, however, it recurred in 3 of 5 patients without complete medications. As a whole, cardiopulmonary arrest recurred in 3 of 12 patients (25%) within one year after the onset of symptoms. To reduce the possibility of the recurrence of arrest and improve prognosis in patients with previous successful cardiac resuscitation, intensive examinations for the causes, therapy including EPS and ergonovine CAG, full medications and surgical treatment may be helpful.

Adult↗
PubMed1991

[Targeting cancer chemotherapy for metastatic liver cancer--effects of DSM on hepatic hemodynamics and on clinical outcome].

The effects of intra-arterial infusion of degradable starch microsphere (DSM) on hepatic hemodynamics were studied in 22 patients with metastatic liver cancer and the clinical outcome with mitomycin C (MMC) combined with DSM was reported herein. Hepatic arterial blood flow, measured with a transit-time ultrasonic blood flow meter, changed 283 +/- 27 ml/min to 40 +/- 36 ml/min by an hepatic arterial infusion of DSM and, a mean occlusion time aS 24 +/- 11 min. Combined infusion with DSM and MMC reduced MMC levels in the peripheral blood at 0.0248 less than p less than 0.0421, compared with those by an infusion with MMC alone and consequently, these findings proved to result from intrahepatic accumulation of MMC. RI-angiography using 99mTc-macroaggregated albumin (99mTc-MAA) was performed to examine hemodynamic changes in the metastatic liver and, a tumor (T) to non-tumor (N) ratio of 99mTc-MAA accumulation increased 0.37 to 0.62 by combined use of DSM. Thus, an intra-arterial infusion combined DSM and MCC was performed for 22 patients with unresectable hepatic metastases. Tumor regression was observed in 16 patients (73%). Side effects possibly attributable to DSM was transient nausea and vomiting. These results show that combined use of DSM is effective for intra-arterial chemotherapy against metastatic hepatic cancer.

Aged↗
PubMed1990

The poliovirus receptor protein is produced both as membrane-bound and secreted forms.

Both genomic and complementary DNA clones encoding poliovirus receptors were isolated from genomic and complementary DNA libraries prepared from HeLa S3 cells, respectively. Nucleotide sequence analysis of these cloned DNAs revealed that the poliovirus receptor gene is approximately 20 kb long and contains seven introns in the coding region, and that at least four mRNA isoforms referring to the coding sequence are generated by alternative splicing and appear to encode four different molecules, that is, PVR alpha, PVR beta, PVR gamma and PVR delta. The predicted amino acid sequences indicate that PVR alpha and PVR delta, corresponding to the previously described cDNA clones H20A and H20B, respectively, are integral membrane proteins while the other two molecules described here for the first time lack a putative transmembrane domain. Mouse cell transformants carrying PVR alpha were permissive for poliovirus infection, but those carrying PVR beta were hardly permissive. In contrast to PVR alpha, PVR beta was not detected on the surface of the mouse cell transformants but was detected in the culture fluid by an immunological method using a monoclonal antibody against poliovirus receptor. Three types of splicing products for PVR alpha, PVR beta and PVR gamma were detected by polymerase chain reactions using appropriate primers in poly(A)+ RNAs of the brain, leukocyte, liver, lung and placenta of humans; the choice of primers used did not permit detection of PVR delta. In situ hybridization using a cDNA fragment as a probe demonstrated that the PVR gene is located at the band q13.1----13.2 of human chromosome 19.

Amino Acid Sequence↗
PubMed1990

Etoposide protects mice from radiation-induced bone marrow death.

Etoposide is known to inhibit the activity of topoisomerase II, and to possess radiosensitizing effects. In this paper we show that pretreatment of mice with etoposide one day before whole-body irradiation had a protective effect against radiation-induced bone marrow death. The LD50/30 of mice given radiation alone was 8.26 Gy while that of mice given etoposide one day before whole-body irradiation was 10.35 Gy. The number of endogenous colony-forming units surviving in whole body-irradiated mice was significantly increased by pretreatment with etoposide.

Animals↗
PubMed1990

Both Pit-1 and the estrogen receptor are required for estrogen responsiveness of the rat prolactin gene.

To examine the functional relationship between distinct cis-active elements within the distal enhancer region of the rat PRL gene, we have used deletional and mutational analysis of that region in transient transfection studies in GH3 pituitary tumor cells. Results from these studies demonstrate that the region of the PRL distal enhancer containing the Pit-1-binding sites is critical not only for enhancer activity and the response to cAMP, but also for the response to estradiol. An interaction of the estrogen receptor with factors conferring basal enhancer activity is suggested by studies with a mutant distal enhancer region in which the PRL estrogen response element was converted to a palindromic estrogen response element. To directly examine potential interactions, cotransfection studies using PRL distal enhancer reporter gene constructs and expression vectors for Pit-1 and rat estrogen receptor were performed in two heterologous cell lines. The activity of the reporter gene under the control of the PRL distal enhancer linked to either the thymidine kinase promoter or the PRL proximal promoter was not significantly altered by cotransfection with the Pit-1 expression vector in COS-1 or RAT-1 cells. Coexpression of these reporter constructs and an expression vector for estrogen receptor resulted in only a slight response to estradiol. However, when both Pit-1 and estrogen receptor were cotransfected with the distal enhancer reporter gene, a marked induction was observed in response to estradiol, and this activity was dependent upon the concentration of the Pit-1 expression vector.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Coronary artery fistula with left or right ventricular communication and sinus-node dysfunction.

Coronary artery fistulae that communicate with the left ventricle are quite rare; those accompanied by sinus-node dysfunction are even more unusual. We report 2 cases of congenital coronary-artery-to-left-ventricle fistula with sinus-node dysfunction. In each of these patients, fistulae arose from both left and right coronary arteries. One patient had, in addition, a right coronary artery fistula that communicated with his right ventricle. Sinusnode dysfunction encountered in these 2 patients was likely caused by chronic general ischemia arising from a steal syndrome associated with the fistulae.

Journal Article↗
PubMed1990

Chromosome aberration frequencies produced by a 70-MeV proton beam.

The effectiveness of a 70-MeV proton beam in the induction of chromosome aberrations was studied. We employed peripheral lymphocytes and analyzed the frequencies of dicentrics and rings after irradiation at doses ranging from 0.1 to 8.0 Gy at various depths within a Lucite phantom. The frequency of chromosome aberrations after irradiation with an unmodulated proton beam at 5 mm showed a dose-response relationship similar to that of 60Co gamma rays. However, irradiation at greater depths with the spread-out Bragg peak induced higher aberration frequencies at doses lower than those with gamma rays. Furthermore, the distribution curve of chromosome aberration frequencies as a function of depth was found to be slightly different from the physically measured depth-dose curve. With the spread-out Bragg peak the biological effects were more marked at greater depths, resulting in a distribution of relative biological effectiveness values. The results obtained from chromosome aberration analysis may not be related directly to those for the relationship between dose and cell killing. Slight differences in values for relative biological effectiveness due to the change of dose and site of proton beam irradiation may not be important for practical proton beam therapy, but may be important in the prevention of late radiation injuries.

Adult↗
PubMed1990

Frequency of micronuclei in hepatocytes following X and fast-neutron irradiations--an analysis by a linear-quadratic model.

The usefulness of the micronucleus assay for investigating the radiation response of hepatocytes was examined. The frequency was defined as the ratio of the total number of micronuclei to the number of hepatocytes examined. The dose-response curves were curvilinear after X rays and linear after neutrons. These dose-response curves were analyzed by a linear-quadratic model, frequency = aD + bD2 + c. The a/b ratio was 3.03 +/- 1.26 Gy following X irradiation. This value is within the range of the alpha/beta ratios reported by others using the clonogenic assay of hepatocytes. While the a/b value for neutrons was 24.3 +/- 11.7 Gy, the maximum relative biological effectiveness of neutrons was 6.30 +/- 2.53. Since the micronucleus assay is simple and rapid, it may be a good tool for evaluating the radiation response of hepatocytes in vivo.

Animals↗
PubMed1990

[A case of ruptured pseudoaneurysm of the aortic arch associated with hemoptysis and hoarseness].

We experienced a case of the ruptured pseudoaneurysm of the aortic arch. Patient complained left anterior chest pain, back pain and hoarseness. Considering the past history of pulmonary tuberculosis, emergency operation was performed median sternotomy approach and using aortic occlusion balloon catheter method and selective cerebral perfusion. Woven dacron graft was anastomosis intraluminal aneurysm. Postoperative course was good. Median sternotomy approach and AOBC method were better than intercostal approach method, because of a little bleeding, short operative time and method.

Aged↗
PubMed1990

[Long-term follow-up study of I-131 therapy for Graves' disease--index associated with late-onset hypothyroidism].

We have studied the follow-up of thyroid function in the patients with late-onset hypothyroidism and euthyroidism after I-131 therapy of hyperthyroidism. Thirty three patients who did not need the thyroid treatment until ten years after I-131 therapy were classified as euthyroid group. And eleven patients who needed the thyroid supplement of thyroid hormone for late-onset hypothyroidism were classified as hypothyroid group. Patients in both groups who required only a single dose of I-131 for successful treatment of hyperthyroidism had similar age, gland size, 24 hour I-131 uptake, pretreatment serum T3 uptake level and T4 concentration, and I-131 treatment dose. Subclinical hypothyroidism occurred in 28.6% of euthyroid group and 66.7% of hypothyroid group four months after I-131 therapy. The levels of T3 were recovered to higher than normal range at 6 months in euthyroid group, while the levels of T3 were kept within the normal range in the seventy percent of hypothyroid group. Patients who were still lower in the level of T3 uptake than normal range at 6 months had a higher incidence of late-onset hypothyroidism. Our observation showed no significant difference in the course of follow-up studies after I-131 therapy between the patients with late-onset hypothyroidism and euthyroidism.

Adult↗