Search PubMed⌕ Search

Biomedical subjects

Y Ando

Publications and source records attributed to Y Ando.

At least 793 records · Page 44Linked to original sources
PubMedDate not supplied

Estimation of the area under the concentration-versus-time curve of carboplatin following irinotecan using a limited sampling model.

OBJECTIVES: The aim of this study was to develop limited sampling models for estimating the area under the concentration-versus-time curve (AUC) of carboplatin. METHODS: Based on pharmacokinetic analyses of 14 patients who received 300 mg x m2 of carboplatin over a 90-min infusion following irinotecan, we developed limited sampling models with stepwise multiple linear regression analysis. We validated these models to be unbiased and precise using pharmacokinetic data of a second group of 14 patients. We also compared the observed and the predicted AUC in the patients using Calvert's formula with the patients' renal function. RESULTS: We developed the following models: AUC (mg x ml(-1) x min) = 0.784 x C4 + 1.30 (r2=0.930) and AUC=0.100 x C0.25 + 0.597 x C4 + 0.140 (r=0.992), where C0.25 and C4 denote unbound plasma concentrations (microg x ml(-1)) of carboplatin at 0.25 h and 4 h after the end of infusion, respectively. These models were validated to be unbiased and precise: a mean prediction error (MPE) with standard deviation (SD) = 2.41 (9.45)% and a root mean squared error (RMSE) = 9.42% for the one-sample model, and MPE with (SD) = 1.22 (5.56)% and RMSE = 5.49% for the two-sample model. We also calculated predicted AUC in the patients using Calvert's formula: MPE with (SD)= -5.87 (21.5)% and RMSE = 21.5%. CONCLUSIONS: These estimations were, as expected, more accurate than the prediction using Calvert's formula based on patients' renal function. The result of this study confirmed the idea that the pharmacokinetic parameters derived from limited sampling models would be more suitable for pharmacokinetic analysis of carboplatin than those obtained using Calvert's formula.

Adult↗
PubMedDate not supplied

Clinical application of a magneto-optical disk image filing system/image save and carry (ISAC) system.

We propose the utilization of portable magneto optical disks for image filing. The main problems in PACS are the need for a high-speed local area network (LAN) and a large mass storage device. An image filing system--image save and carry (ISAC)--is one solution for these problems in present PACS and requires minimal additional hardware and cost for the installation. Whenever a patient is examined, the clerk carries the medical record and the ISAC magneto-optical disk for recording image data, and after inspection records the image data into the magneto-optical disk. We investigated the number of image retrievals done for inpatients and outpatients in 1988 at our radiation therapy department. The data storage requirements were on the average 18.5 MB for outpatients and 173.9 MB for inpatients. An ISAC display console needs also an easy-to-use man/machine interface for specifying images and image display characteristics in order to realize the ISAC system.

Computer Systems↗
PubMedDate not supplied

Intrathymic inoculation of donor HLA class I-derived peptide generates donor-specific CD4+CD25+ regulatory T cells.

CD4(+)CD25(+) regulatory T cells are selected in the thymus to control autoreactive thymic escapees preventing autoimmunity that cannot be achieved by negative selection or deletion alone, thus playing an important role in the maintenance of immunological homeostasis. Not only significant in preventing autoimmunity, CD4(+)CD25(+) regulatory T cells have also been shown to be involved in allograft tolerance in organ transplantation. We have formerly introduced two lines of HLA class I transgenic mice to elucidate the role of HLA class I molecules in transplantation biology. Using a heterotopic cardiac transplantation model, we show herein that intrathymic inoculation of donor HLA class I-derived synthetic peptide results in the generation of CD4(+)CD25(+) regulatory T cells, which induce graft specific tolerance without any preconditioning of the recipient or use of immunosuppressive drugs. This study provides evidence of the novel therapeutic potential of CD4(+)CD25(+) regulatory T cells for clinical transplantation.

Amino Acid Sequence↗
PubMedDate not supplied

Mastopathy-mimicking ultrasonographic appearance in a case with Burkitt's lymphoma.

We report a case of Burkitt's lymphoma, which was suspected to involve both breasts. US showed a replacement of the normal breast tissues by a diffusely mixed or mottled pattern of echo texture, associated by hypoechoic cyst-like masses with slight internal echogenicity. This pattern was indistinguishable from the sonographic changes produced by a mastopathy. These findings disappeared after successful chemotherapy for the Burkitt's lymphoma, suggesting that the ultrasonographic pattern of mastopathy was caused by the infiltration of the breast tissues by the lymphomatous cells.

Breast Neoplasms↗
PubMedDate not supplied

Unusual priming mechanism of RNA-directed DNA synthesis in copia retrovirus-like particles of Drosophila.

Drosophila cells contain virus-like particles (VLPs) containing 5 kilobases (kb) of RNA (VLP H-RNA) homologous to the transposable element copia. The identity between VLP H-RNA and copia DNA has previously been confirmed at the nucleotide sequence level and reverse transcriptase activity is also detected in the VLPs. These results suggest that VLPs and copia are derivatives of viral particle and provirus forms, respectively, of the copia retrovirus-like particle. If the copia retrovirus-like particle replicates by a mechanism similar to the mechanism of vertebrate retroviral replication, a cellular transfer RNA would prime synthesis of the first DNA strand. We show that this is indeed so but that copia retrovirus-like particle has a novel type of priming mechanism; the first DNA extension does not start from the 3' end of a tRNA, but from an internal site (two nucleotides after the anticodon loop) of the Drosophila initiator methionine tRNA (tRNAMeti).

Animals↗
PubMedDate not supplied

Effect of chilling on platelet cyclic adenosine 3:5-monophosphate and adenylate cyclase activity.

Exposure of platelets to 1 C led to a transient increase in cyclic AMP levels (determined either by a protein binding method or by radioimmunoassay) within five to ten minutes reaching a maximum 10 to 15 minutes after chilling was begun and returning subsequently to baseline values. Addition of EDTA to the platelet suspension medium prevented this increase. Rewarming at 37 C produced a sudden reduction in platelet cyclic AMP. To determine whether the cold-induced increase in cyclic AMP was due to a transient stimulation of platelet adenylate cyclase or a rapid inhibition of phosphodiesterase, these enzymes were assayed in ruptured platelet suspensions. Platelet adenylate cyclase activity was found to possess certain characteristics similar to those of the enzyme derived from other sources but there was a marked potentiation of fluoride-stimulated adenylate cyclase activity by 0.001 M EDTA. This effect was limited to low EDTA concentrations. Exposure of platelets to 1 C for up to 60 minutes did not increase adenylate cyclase activity but lowered it substantially compared with controls kept at room temperature. Phosphodiesterase activity at 1 C was depressed sooner and to a greater extent than was adenylate cyclase. The transient rise in cyclic AMP levels in chilled platelets appears to be due to a disproportionate reduction of cyclic nucleotide phosphodiesterase activity.

Adenosine Triphosphate↗
PubMedDate not supplied

Effect of plasmapheresis as initial monotherapy in a case of anti-neutrophil cytoplasmic autoantibody positive crescentic glomerulonephritis.

The effect of plasmapheresis (PP) monotherapy was evaluated in a 77 year old man with crescentic glomerulonephritis (CrGN). Because both anti-neutrophil cytoplasmic myeloperoxidase autoantibody (MPO-ANCA) and circulating immune complex (IC) were positive, removal of these substances was expected to be beneficial. Thus, the treatment was started with PP alone. During 2 month's time, three series of PP monotherapy were performed: three sessions of plasma exchange (PEX) with fresh frozen plasma (FFP); two sessions of double filtration plasmapheresis (DFPP); followed by another two sessions of PEX. The ANCA remained suppressed for 4 weeks after the first PEX, and increased thereafter. Subsequent DFPP caused a rebound in ANCA titer, whereas the second PEX suppressed ANCA for 1 week. Although creatinine clearance (Ccr) improved from 9.3 to 15 ml/min after the first PEX, and this level was maintained, ANCA increased again after the second PEX. Therefore, the patient was treated with methylprednisolone semi-pulse therapy (500 mg/day for 3 days), followed by mild "cocktail" therapy. In 2 weeks ANCA and IC became negative, and Ccr further improved to 20 ml/min. Thus, PP, when performed alone, was shown to be partially effective, arresting the progression of renal damage in the present case. These observations also argue for the advantage of PP, especially PEX, as an adjunct therapy to immunosuppressive therapy in CrGN.

Aged↗
PubMedDate not supplied

Utility of the inferior vena cava diameter as a marker of dry weight in nonoliguric hemodialyzed patients.

We have previously reported that the maximal inferior vena cava (IVC) diameter during quiet expiration (IVCe) measured by ultrasonography correlates well with the amount of body fluid, especially the circulating blood volume(2) and proposed using the criteria of IVC diameter to determine dry weight (DW) in anuric hemodialyzed (HD) patients: standard IVCe of pre- and post-HD are 14.9 +/- 0.4 and 8.2 +/- 0.3 mm, respectively (1). However, the same post-HD IVC criterion should not be applied to nonoliguric HD patients because it could result in rapid deterioration of residual renal function due to forced dehydration. Although the biochemical DW marker plasma atrial natriuretic peptide (ANP) is useful to evaluate hypervolemia but not hypovolemia, both hyper- and hypovolemia can be detected by IVC measurement. In the present study, we investigated whether the IVC diameter serves as an optimal evaluation of DW in nonoliguric HD (NO-HD) patients, avoiding not only overhydration but also dehydration. The IVCe and plasma ANP levels were measured in 14 euvolemic patients with chronic renal failure at conservative period (CP-CRF) and 11 NO-HD patients, in whom the average daily urine volume was more than 500 ml/day. In NO-HD patients, DW was adjusted to attain the euvolemic state with normotensive blood pressure, lack of edema, and lack of temporal oliguria after HD. The ANP in CP-CRF patients was 109.3 +/- 15.3 pg/ml, and pre- and post-HD ANP levels in NO-HD patients were 145.3 +/- 23.5 and 97.5 +/- 13.5 pg/ml, respectively. IVCe in CP-CRF was 13.4 +/- 0.9 mm, and pre- and post-HD IVCe in NO-HD patients were 14.2 +/- 1.0 mm and 11.9 +/- 0.9 mm, respectively. Although the post-HD IVCe was greater (i.e., less hypovolemic) than that in anuric HD patients, and close to the IVCe in CP-CRF, pre-HD IVCe was comparable with that in anuric HD patients. In addition, the pre-HD ANP level was no higher than that in CP-CRF. Thus, in NO-HD patients, the post-IVCe of 11.9 +/- 0.9 mm would be a marker for an appropriate DW setting avoiding severe post-HD dehydration as well as excessive hypervolemia during the interdialytic period.

Adult↗
PubMedDate not supplied

Sodium ion specifically modifies plasma ionized calcium concentration.

BACKGROUND/AIM: Recently, we observed a progressive decline in the plasma ionized calcium (iCa) concentration after ingestion of Na-free beverage. Although both plasma pH and Na significantly correlated with iCa, the correlation of the latter was stronger than that of the former. Therefore, we explored the effect of Na on plasma iCa. METHODS: Pooled human plasma was diluted with normal saline, 5% glucose, 0.9% KCl, or distilled water to examine the effect of plasma dilution on iCa. Also, to evaluate the effects of an isovolemic increase in ion concentration and osmolarity on plasma iCa, NaCl, KCl, and D-glucose were added to plasma. Electrolytes (Na(+), K(+), Cl(-), iCa, HCO(-)(3)), pH, and osmolarity were measured by using ion-selective electrodes. RESULTS: In the plasma dilution study, although all solutions significantly decreased the iCa concentration, the decrease in iCa concentration in the normal saline treated solution was significantly lower than in others. When the plasma osmolarity was isovolemically increased, the iCa concentration significantly increased in parallel with the increase in osmolarity in the NaCl group (r = 0.604, p < 0.01, n = 50). In contrast, no significant change in the iCa concentration was seen in the other solutions. NaCl did not increase, but rather decreased the iCa concentration when added to a protein-free solution. CONCLUSION: The present study demonstrated that Na specifically affects plasma iCa independently of pH, presumably via modulating Ca binding to plasma proteins.

Analysis of Variance↗
PubMedDate not supplied

Pyrene fluorescence: a potential tool for estimation of short-range lateral mobility in membranes of living renal epithelial cells.

The excimer-to-monomer (E/M) fluorescence ration of pyrene (p) and its derivatives has been found to correlate with membrane fluidity. We explored the possible use of this method in living renal epithelial cells. In Modin-Darby canine kidney cells, successful fluorescent labeling was obtained with p-cholesterol, p-trimethylammonium (TMA), p-sulfonamidethyl-TMA, p-butyrate, p-propanoate or p-dodecanoate. Among them, the labeling with p-cholesterol was most stable. The whole cell cholesterol content did not significantly increase after loading p-cholesterol and the probe incorporated was not degraded. The E/M ratio changed reproducibly and significantly by temperature change, a standard method to alter membrane fluidity. Thus, the E/M ratio of p-cholesterol fluorescence is suggested to be a potential parameter of membrane fluidity in living renal epithelial cells and might be useful in investigating the relationship between the physical state of the membrane and epithelial function.

Animals↗