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Biomedical subjects

S Koike

Publications and source records attributed to S Koike.

At least 19 recordsLinked to original sources
PubMed1992

A second gene for the African green monkey poliovirus receptor that has no putative N-glycosylation site in the functional N-terminal immunoglobulin-like domain.

Using cDNA of the human poliovirus receptor (PVR) as a probe, two types of cDNA clones of the monkey homologs were isolated from a cDNA library prepared from an African green monkey kidney cell line. Either type of cDNA clone rendered mouse L cells permissive for poliovirus infection. Homologies of the amino acid sequences deduced from these cDNA sequences with that of human PVR were 90.2 and 86.4%, respectively. These two monkey PVRs were found to be encoded in two different loci of the genome. Evolutionary analysis suggested that duplication of the PVR gene in the monkey genome had occurred after the species differentiation between humans and monkeys. The NH2-terminal immunoglobulin-like domain, domain 1, of the second monkey PVR, which lacks a putative N-glycosylation site, mediated poliovirus infection. In addition, a human PVR mutant without N-glycosylation sites in domain 1 also promoted viral infection. These results suggest that domain 1 of the monkey receptor also harbors the binding site for poliovirus and that sugar moieties possibly attached to this domain of human PVR are dispensable for the virus-receptor interaction.

Amino Acid Sequence↗
PubMed1992

MRL/MP-lpr/lpr mouse as a model of immune-induced sensorineural hearing loss.

Hearing acuity and inner ear disorders of MRL/lpr mice, bred for the study of autoimmune disease, were examined in comparison to those of BALB/c mice. The auditory brain stem response threshold of 20-week-old MRL/lpr mice was significantly higher than that of BALB/c mice of the same age (p < .01). The pathologic changes of 20-week-old MRL/lpr mice were characterized by the degeneration of intermediate cells, widened intercellular spaces, and immunoglobulin G deposition on the basement membrane of strial blood vessels as well as in the basal infolding of strial marginal cells, which were absent in BALB/c mice. That there were no other evident pathologic findings in the cochlea or middle ear suggests that these changes in the stria vascularis seemed to be responsible for the sensorineural hearing loss of this mouse. The MRL/lpr mouse was thought to be a good experimental model to study the spontaneous sensorineural hearing loss caused by an immune reaction.

Animals↗
PubMed1992

[Health effects of non-occupational exposure to asbestos].

Mesothelioma has occurred in a relative large number not only among miners but also among non-occupationally exposed persons living in the northwestern region of Cape State of South Africa, where crocidolite is mined and transported. The long-term residents of Thetford Mines in Quebec Province, Canada, who have never engaged in mining and milling of chrysolite have not shown an excess mortality of respiratory diseases. Tremolite in soil is responsible for mesothelioma among residents of certain geologic regions such as Cyprus, Corcica, northwestern Greece and Turkey. An increased prevalence of malignant mesothelioma has been reported among residents of three Turkish villages due to exposure to erionite fibers having a high carcinogenic potency. Mesothelioma has infrequently developed in wives who were exposed while washing the work clothes of their husbands contaminated with asbestos, especially amphiboles. The levels of airborne asbestos in public buildings and schools in the U.S.A. and England having walls and ceilings constructed with asbestos containing materials are approximately 1/100 of the permissible concentration of 0.2 f/cm3. The estimated risk from asbestos exposure in schools and buildings is lower than the level of other risks in other society. During the work of removing asbestos from buildings the asbestos concentration is remarkably increased and this persists for many weeks thereafter. The level of asbestos fibers released from brake linings of motor vehicles is higher along roads with heavy traffic, at intersections, and near toll booths than elsewhere. The concentration of asbestos fibers released from motor vehicles is generally low and not of the level to induce mesothelioma.

Air Pollution, Indoor↗
PubMed1992

[A case of acute right ventricular infarction and life-saving right ventricular assistance following emergency coronary revascularization and resection of a left ventricular aneurysm--discussion of indication and proper assist flow volume].

Right ventricular assistance (RVA) using centrifugal pump in combination with IABP was used to treat a patient who was difficult to wean from a cardiopulmonary bypass following emergency coronary revascularization and resection of a ventricular aneurysm performed to treat acute right ventricular infarction due to a PTCA complication. After 131 hours of RVA at 3.2 to 4.8 l/min, it was possible to remove the pump. No heparin was administered during this time, changing the pump head twice, was used for 64 and 50 hour period, no thrombi were detected either time. After being weaned from RVA, the patient developed severe respiratory dysfunction, but on the 10th postoperative day (POD) IABP was weaned, and on the 13th POD the artificial respirator was withdrawn. The results of the postoperative cardiac catheterization were favorable, the patient was discharged on the 57th POD, and has returned to society at the present time. The indications for RVA include a central venous pressure > 20 mmHg and a cardiac index < 1.8 l/min/m2, and tissue perfusion pressure and general preoperative condition should severe as guides. The higher the assisted flow volume the more efficacious in relieving ventricular load, but, since there is a limit to how much the left ventricle and lungs can withstand, it should not exceed levels which ensure the maintainance of cardiac output and tissue perfusion pressure.

Angioplasty, Balloon, Coronary↗
PubMed1992

[A case of an unusual type of coarctation of the aorta terminating in the complete obstruction].

A 19 year-old girl with an unusual type of coarctation of the aorta terminating in complete obstruction is presented. At the age of 5 years, she was diagnosed by aortography to have coarctation of the aorta of type IV C according to Edward's classification. No surgical treatment was performed at that time because her growth was good and she didn't have hypertension. During the follow-up period, marked hypertension developed, and she was readmitted. The aortogram revealed a bicuspid aortic valve and total obstruction of the descending thoracic aorta at the site where coarctation was noticed previously. The abdominal aorta distal from the obstruction site was filled through rich collateral circulation. As these angiographic interval changes are very rare, we discussed the genesis of obstruction and operative indication by reviewing the literature.

Adult↗
PubMed1992

[Treatment of liver metastases from gastric cancer].

Nine patients with liver metastases from gastric cancer were treated in our department since 1986. Hepatectomy was performed in 3 cases and hepatic arterial infusion chemotherapy was performed in 6 cases. In 3 patients in whom hepatectomy was performed, the extent of liver metastases showed 2 H1 and 1 H2. One has survived for 20 months, but the other 2 died after 5 and 7 months, respectively. In 6 patients in whom hepatic arterial infusion chemotherapy was performed, the extent of liver metastases was H3. These patients were treated with 5-FU.EPIR.MMC (3 cases), CDDP.MMC (1 case), MMC only (1 case) and 5-FU.ADM.MMC.CDDP (1 case). This treatment revealed a 50% response rate (CR 1, PR 2). The patient with CR has survived for 6 years and 2 patients with PR died after 8 and 12 months. The patient with CR showed high AFP level (55, 480 ng/ml), and 2 patients with PR showed high AFP level (24, 327 ng/ml) or high CEA level (3,903 ng/ml). The prognosis of hepatectomy for liver metastases from gastric cancer was not so good. Hepatic arterial infusion chemotherapy seemed to be a useful treatment for liver metastases from gastric cancer.

Aged↗
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↗