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T Ichihara

Publications and source records attributed to T Ichihara.

At least 91 records · Page 5Linked to original sources
PubMed1996

[Scatter and attenuation correction for quantitative myocardial SPECT imaging].

We performed scatter and attenuation compensation in 201Tl myocardial SPECT using the triple-energy-window (TEW) scatter correction method and 99mTc transmission scan (TCT). A dual-headed SPECT gammacamera system equipped with parallel-hole collimators was employed for imaging and a sheet source for TCT was attached to the surface of one of the two detectors. Two imaging protocols, a sequential mode and a simultaneous mode, were examined. In the sequential mode, TCT was performed prior to the administration of the tracer and then ECT was carried out. On the other hand, the injection was followed by a simultaneous transmission-emission scan, in the simultaneous mode. Results of phantom studies showed that reconstructed SPECT values of the whole myocardium were almost equal to the true value with errors of less than 5 per cent, and that more homogeneous images were obtained by performing scatter and attenuation correction. We conclude that this correction method was clinically practical and cost-effective because it uses parallel-hole collimators and does not require fan-beam collimators which may produce truncation artifacts.

Heart↗
PubMed1996

[Seckel's syndrome].

Explore the source record for details and available documents.

Abnormalities, Multiple↗
PubMed1995

Intraoperative peritoneal washing cytology with the rapid immunoperoxidase method using microwave irradiation.

The rapid immunocytochemical staining of gastrointestinal cancer-associated antigens, carcinoembryonic antigen (CEA) and carbohydrate antigen 19-9 (CA19-9), for intraoperative peritoneal washing cytology of pancreatic or biliary carcinoma can be completed in only 25 minutes by using microwave irradiation to accelerate incubation of the primary antibody. Only 3-second irradiation at 500 W for fresh smears produced specific antigen staining of malignant cells similar to that obtained with longer incubation, and the sensitivity of intraoperative cytology was greater than by the conventional staining method. The rapid immunocytochemical staining method of peritoneal washings at laparotomy can provide sensitive information for determining more aggressive therapy for intraperitoneal spread of malignant cells before closing the abdominal wall.

Aged↗
PubMed1995

A new device for exposing the circumflex coronary artery.

We have devised a new retractor for use in coronary artery bypass grafting that is made from three woven Teflon tapes. This method allows sufficient counterclockwise rotation of the heart, provides excellent exposure of the posterior and inferior coronary artery systems, and creates a horizontal surgical plane for the circumflex anastomosis.

Coronary Artery Bypass↗
PubMed1995

Flow cytometric functional analysis of multidrug resistance by Fluo-3: a comparison with rhodamine-123.

Using four cell lines including drug-sensitive K562/Parent cells, P-glycoprotein (Pgp)-mediated multidrug resistant (MDR) K562/VCR, K562/ADR and revertant K562/ADR-R cells, two fluorescent agents, Fluo-3 and rhodamine-123 (Rh-123), were compared as indicators in a functional assay of MDR. Cells were incubated with 4 microM Fluo-3 or 1 microM Rh-123 for 45 min and then the intracellular accumulation of the agent was measured using a flow cytometer. Verapamil (20 microM) or cepharanthine (biscoclaurine alkaloid, 10 microM) was added just before the fluorescent agents. Efflux patterns were also studied 60 min after incubation with or without verapamil and cepharanthine. Increased intracellular accumulation and a delayed efflux pattern of Fluo-3 by verapamil and cepharanthine were demonstrated in multidrug resistant K562/VCR and K562/ADR cells, indicating that Fluo-3 is another good indicator of MDR. However, a similar, but lower, increase in uptake and a delayed efflux pattern of Fluo-3 by verapamil and cepharanthine were also demonstrated even in Pgp-non-overexpressed K562/Parent cells. In contrast, accumulation of Rh-123 was not affected by verapamil and cepharanthine. To further study the Pgp dependency of Fluo-3, another cell line, K562/NC16 expressing minimum MDR1 mRNA, was cloned. Increased uptake and a delayed efflux pattern of Fluo-3, but not Rh-123, with verapamil or cepharanthine were again demonstrated in K562/NC16 cells, indicating that intracellular accumulation of Fluo-3 may be non-specifically influenced by verapamil and cepharanthine at very low levels of Pgp-related MDR, while the influx and efflux patterns of Rh-123 may be specifically affected by Pgp overexpression.

ATP Binding Cassette Transporter, Subfamily B, Mem↗
PubMed1995

Mitochondrial encephalomyopathy with A to G transition of mitochondrial transfer RNA(Leu(UUR)) 3,243 presenting hypertrophic cardiomyopathy.

In a 24-year-old woman with mitochondrial encephalomyopathy presenting hypertrophic cardiomyopathy, microscopical examination of myocardial biopsy specimen disclosed severe vacuolar degeneration of myocardium and aggregates of enlarged mitochondria with proliferated cristae. Limb muscle biopsy specimen showed "ragged-red fibers" light microscopically and enlarged abnormal mitochondria with markedly increased cristae ultrastructurally. Mitochondrial DNA analysis by polymerase chain reaction (PCR) revealed an A-to-G transition in the mitochondrial transfer RNA(Leu)(UUR) gene at nucleotide position 3,243 which is reported to be associated with mitochondrial myopathy, encephalopathy, lactic acidosis, and stroke-like episodes (MELAS). However, the clinical features of this case, presenting mainly cardiac abnormalities, were not consistent with the typical MELAS.

Adult↗
PubMed1995

[A successful surgical case of bilateral partial anomalous pulmonary venous connection without atrial septal defect].

We performed the new operative method for bilateral partial anomalous pulmonary connections (PAPVC) without atrial septal defect (ASD). A 11-years-old boy was admitted for operation. The right upper pulmonary vein returned to the superior vena cave (SVC), and left upper pulmonary vein returned to the innominate vein. Atrial septum was intact. The Qp/Qs was 1.94. The right atrium (RA) was opened and ASD was created. Continuity between the distal end of the SVC and RA was re-established by end-to-end anastomosis to the right atrial appendage. The proximal end of the SVC was closed. The right anomalous pulmonary vein remained in situ on the lower segment of SVC, blood being directed to the left atrium (LA) through the created ASD by suturing the posterior flap of RA incision to the atrial septum well away from the sinoatrial node and artery, anomalous pulmonary vein and cavoatrial junction. The anomalous left vertical vein was dissected up to the innominate vein. The left pulmonary vein was mobilized as much as possible, and was anastomosed to the posterior wall of LA by end-to-side fashion. He has normal sinus rhythm and no evidence of pulmonary venous obstructions on both sides. We support the efficacy of this method as an alternative in the management of this disorder.

Brachiocephalic Veins↗
PubMed1995

[Operative procedures for mitral prolapse and its clinical results].

Mitral valve plasty is the very important procedure for treatment of mitral regurgitation from the view point of post operative quality of life because patients may be possible to be free from postoperative drug therapy especially when the normal sinus rhythm is restored even if the concomitant maze procedure is necessary. In this report, 36 patients who underwent mitral valve plasty for mitral regurgitation were evaluated. In 18 patients who had posterior leaflet prolapse, McGoon's procedure was performed. Two of them required secondary mitral valve replacement 4 days after operation. Reoperation disclosed tissue detachment at the mitral annulus sutures which were not reinforced by a ring. It was considered that annular ring plasty is preferable after resection of prolapsed posterior leaflet by McGoon's procedure. Out of 18 patients who had mitral valve prolapse including anterior leaflet, 8 patients underwent such conventional procedures as transfer of chordae tendinae, leaflet resection and shortening of chordae. Four patients resulted in second look mitral valve replacement 11 days to 1 month after mitral valve plasty. On the contrary, the clinical results of repair of chordae tendineae with artificial chordae of extended polytetrafluoroethylene (ePTFE) were good. It is concluded that the resection of prolapsed leaflet and reconstruction of the annulus with reinforcement using a prosthetic ring is preferable for the posterior leaflet prolapse. For the anterior leaflet prolapse, good results can be obtained by replacement of chordae tendineae with ePTFE sutures.

Adolescent↗
PubMed1995

[Quantitative brain SPECT imaging with scatter and attenuation compensation: comparison of sequential and simultaneous acquisition of transmission and emission data].

Scatter and attenuation correction for brain SPECT of a phantom and a normal volunteer was performed using the Triple Energy Window method combined with a transmission scan. 99mTc-ECD and 99mTc solution were used as an emission tracer and a transmission source, respectively. We employed a triple-headed SPECT gammacamera system equipped with fan-beam collimators for acquisition with line transmission sources placed at the focal lines of the fanbeam collimators. Two mode, sequential mode and simultaneous mode, of data acquisition protocols were examined. In the sequential mode, a transmission scan was carried out using three external sources for the brain phantom without emission tracer. After removing all sources, an emission scan was performed on the brain phantom containing the tracer. In the simultaneous mode, the injection was followed by a simultaneous transmission-emission scan using one transmission source. The same study was conducted out for the normal volunteer, after confirming the effectiveness of these protocols with phantom studies. Corrected SPECT count values obtained with two protocols were almost identical. Simultaneous mode had advantages in avoiding misalignment between transmission and emission data and in shorter acquisition time than sequential mode.

Brain↗
PubMed1995

New biotinylating reagent utilizing carbodiimide function.

A biotin derivative having a carbodiimide function (fig.1 Carbo-biotin) was synthesized and reacted with DNAs. This compound was used to label biotin to DNAs, by reaction of carbodiimide group and nucleotides as they form stable adducts. Our experiments showed that it is able to bind to both single and double stranded DNAs. The DNA oligomer labeled with this reagent was shown to hybridize to complementary DNA chain. From our results, this compound is expected to be a useful biotinylating reagent for non-radioactive detection.

Binding Sites↗
PubMed1994

The effects of using a leukocyte removal filter during cold blood cardioplegia.

During myocardial ischemia, neutrophils and platelets exert negative effects on the myocardium. In this study, we used a leukocyte removal filter during cardioplegia, and investigated its effect on myocardial damage during reperfusion by measuring the plasma levels of granulocyte components, platelet components, and cardiac enzymes [creatinine phosphokinase (CK) and creatinine phosphokinase myocardial band (CK-MB)] in 24 patients who underwent cardiopulmonary bypass. The patients were divided into two groups of 12 according to whether or not a filter was placed in the cardioplegic route. Blood samples were drawn directly from the coronary sinus before aortic cross clamping, and at 1, 5, and 15 min after declamping. Group F, which had the filter, showed better cardiac enzyme and lipid peroxidation results than group N, which did not. The results of this study suggest that the application of a filter during cold blood cardioplegia may reduce myocardial damage.

6-Ketoprostaglandin F1 alpha↗
PubMed1994

Mature helper T cell requirement for immunoglobulin production by neonatal native B cells injected intraperitoneally into severe combined immunodeficient (SCID) mice.

It is accepted that human neonatal naive B cells produce mainly IgM in vivo as well as in vitro. Our previous work has demonstrated that i.p. injection of neonatal B cells together with adult mature T cells induces substantial levels of human IgG in the serum of SCID recipient mice. The present study was further attempted to determine the cellular components required for immunoglobulin production by neonatal B cells in SCID mice. When neonatal B and adult T cells were transferred into the SCID mice, human immunoglobulins, largely of IgG, were maximally detected in the serum around 6 weeks after a cell transfer. Depletion of CD4+ T cells from adult T cells resulted in undetectable levels of human immunoglobulin in the serum. By contrast, CD4+ T cell-enriched populations exhibited an enhancing effect on immunoglobulin production by neonatal B cells. Higher levels of immunoglobulin, including IgA and IgM, were detected in the peritoneal fluid than in the serum as early as 2 weeks after the cell transfer. Human T cells expressing activation antigens such as CD45RO and HLA-DR antigens were identified in the peritoneal lavages. These results suggest that neonatal naive B cells are able to differentiate into cells producing all classes of immunoglobulin in the presence of mature CD4+ T cells in a SCID mouse environment. The peritoneal cavity of SCID mice appears to provide a suitable place for immune responses by human cells, possibly in association with a certain xenogeneic reaction.

Adult↗
PubMed1994

Successful treatment of primary sclerosing cholangitis with cyclosporine and corticosteroid.

A case of primary sclerosing cholangitis (PSC) successfully treated with cyclosporine is described. A 65-year-old man who presented with jaundice and anemia was diagnosed as having PSC, accompanied by pancreatic duct abnormalities. Cholangiography and pancreatography showed marked improvements following combined therapy with cyclosporine and methylprednisolone. Cyclosporine seems to be a promising drug for the treatment of patients with PSC. This report reasons that the same disease process affects both the pancreatic ducts and the bile ducts, and that stagnation of pancreatic juice may have a role to play in the pancreatic duct abnormalities.

Aged↗
PubMed1994

[A successful surgical case of atrial septal defect with congenital factor XI deficiency].

We experienced a successful surgical case, who was a 16-year-old boy suffered from atrial septal defect with congenital factor XI deficiency. This disorder is an inherited disorder of blood coagulation characterized by a defect of the intrinsic pathway of thrombin formation and a mild to moderate bleeding tendency, but it can result in severe bleeding in surgical procedures. Open heart surgery in this disorders is rare. Preoperatively we prepared 4000 cc of fresh frozen plasma, but operated without using it. It would appear that the possibility of open heart surgery with congenital factor XI deficiency suggest in this case.

Adolescent↗