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Biomedical subjects

T Irie

Publications and source records attributed to T Irie.

At least 109 records · Page 6Linked to original sources
PubMed1997

Rim enhancement in colorectal metastases at CT during infusion hepatic arteriography. Does it represent liver parenchyma or live tumor cell zone?

PURPOSE: To evaluate the morphologic substrate of the rim enhancement of of colorectal metastases seen at CT during infusion hepatic arteriography (CTIHA). MATERIAL AND METHODS: Eleven sector defects in the enhancing rim of 9 metastases at CTIHA were analyzed. The corresponding pathologic specimens were investigated for sector defects of liver parenchyma. We investigated whether there was a correlation between the central angle of the sector defects of rim enhancement at CTIHA and that of sector defects in the zone of liver parenchyma in histologic slices. The inner and outer diameters of the enhancing rim were also compared with the diameter of the metastases as seen at CT during arterial portography (CTAP). RESULTS: There was a significant correlation between the central angle of sector defects of rim enhancement at CTIHA and the angle of sector defects in the zone of liver parenchyma in histologic slices (p = 0.008, Spearman's test). The diameter of the metastases measured at CTAP was larger than the inner diameter and smaller than the outer diamter of the enhancing rim in CTIHA, i.e. the margins of the nodules as seen in CTAP are located in liver parenchyma and not in tumor tissue. CONCLUSION: The morphologic substrate of the rim enhancement of colorectal metastases seen at CTIHA is liver parenchyma.

Adult↗
PubMed1997

Enhanced topoisomerase I activity and increased topoisomerase II alpha content in cisplatin-resistant cancer cell lines.

Although the combined effects of cisplatin (CDDP) and DNA topoisomerase (Topo) inhibitors have been described in recent literature, little is known about the combined effects and their biological basis in CDDP-resistant cells. The aim of the present study was to elucidate the combined effect of CDDP and Topo inhibitors on CDDP-resistant cells as well as to investigate the biological factors involved in the sensitivity to these anti-cancer agents. We found synergistic actions between CDDP and SN-38 (a Topo I inhibitor) or VP-16 (a Topo II inhibitor) in KFr cells, a CDDP-resistant subline of the KF epithelial ovarian carcinoma cell line, but not in the parent KF cells. We subsequently assayed Topo protein levels and enzymatic activities in two sets of CDDP-sensitive and -resistant cell lines: KF and KFr, and HeLa and HeLa/CDDP. The levels of Topo I protein in the CDDP-resistant cells did not differ from those of their parent cell lines and were unaffected by exposure to CDDP. Topo I enzymatic activity, however, was 2- to 4-fold higher in the CDDP-resistant cell lines than in their respective parent cell lines. In contrast, higher levels of Topo II alpha protein were observed both before and after CDDP exposure in the CDDP-resistant cells than in their controls. However, no difference in Topo II catalytic activity was observed between the CDDP-resistant and -sensitive cells.

Antigens, Neoplasm↗
PubMed1997

Clinical responses and platinum concentrations in tumors after intra-arterial and intravenous administration of cisplatin in the same patients with cervical cancer.

We evaluated 3 patients with advanced cervical cancer treated with cisplatin intra-arterially and intravenously. The dose of cisplatin was 50 mg/m2 in each infusion. Chemotherapy was repeated at 4-week intervals for three to four courses. The clinical response and the tumor concentration of platinum were evaluated in each course. All patients who received the intra-arterial infusion of cisplatin were judged to be responders, whereas none of them responded to the intravenous infusion. The platinum concentration in tumor tissue was significantly higher after intra-arterial infusion of cisplatin (1.97 +/- 0.04 vs. 2.86 +/- 0.10 microg/g). Although there were no apparent differences in side effects between intra-arterial and intravenous routes, 2 of 3 patients rejected an intra-arterial route. The present study suggests that intra-arterial administration of cisplatin may be useful in treating locally advanced cervical cancer.

Adult↗
PubMed1997

Comparative ultrasonographic and angiographic study of carotid arterial lesions in Takayasu's arteritis.

The purpose of this study was to compare the usefulness of ultrasonography to that of angiography for studying arterial lesions in Takayasu's arteritis. Ultrasonographic and angiographic findings from 44 carotid arteries of 22 patients with Takayasu's arteritis (2 men and 20 women; mean age, 41.2 years) were compared. Angiography was used to classify the patency of the carotid arteries into three groups: nonstenotic, stenotic, and occlusive. Ultrasonography was also used to classify the same arteries into four groups: nonstenotic, mildly stenotic, moderately stenotic, and occlusive. Thickness of the wall (intima-media complex) of the carotid artery was measured with high-frequency transducers. Angiography showed 23 carotid arteries to be nonstenotic; 12, stenotic; and 9, occlusive; whereas ultrasonography showed 16 to be nonstenotic; 18, mildly stenotic; 7, moderately stenotic; and 3, occlusive. Results of the two diagnostic modalities correlated closely (P < 0.0001). Ultrasonography, aided by color flow imaging, detected six instances of a marginal but definite blood flow that angiography had failed to reveal. Arterial wall thickness correlated closely with the severity of ultrasonographic stenosis (P < 0.005). This thickness was 1.3 +/- 0.4 mm in the nonstenotic group, 1.6 +/- 0.5 mm in the mildly stenotic group, 2.2 +/- 0.8 mm in the moderately stenotic group, and 1.9 +/- 0.2 mm in the occlusive group. Even the walls of the nonstenotic arteries were significantly thicker than those of the normal carotid arteries (0.7 +/- 0.1 mm, P < 0.01). Ultrasonography appeared to be more useful than angiography in estimating stenotic severity of the carotid artery in Takayasu's arteritis. Characteristic ultrasonic findings included luminal stenosis or occlusion on two-dimensional ultrasonograms, decrease in or lack of flow shown by color Doppler flow imaging, and concentric thickening of the carotid arterial walls. Ultrasonographic mural thickness was the most sensitive indicator of early, latent inflammation.

Adult↗
PubMed1997

Spectroscopic characterization of the inclusion complex of a luteinizing hormone-releasing hormone agonist, buserelin acetate, with dimethyl-beta-cyclodextrin.

Inclusion complexation of buserelin acetate, and agonist of luteinizing hormone-releasing hormone, with dimethyl-beta-cyclodextrin (DM-beta-CyD) in aqueous solution was studied spectroscopically and its mode of interaction was assessed. Ultraviolet absorption and circular dichroism (CD) spectroscopies indicate that the aromatic side chains of buserelin acetate, L-tryptophan and L-tyrosine residues, are incorporated into the hydrophobic environment of the DM-beta-CyD activity. Furthermore, proton and carbon-13 nuclear magnetic resonance spectroscopies suggest that in addition to the two aromatic side chains, a tertiary butyl D-serine residue is inserted into the DM-beta-CyD cavity from the secondary hydroxyl side. On the other hand, the continuous variation plots for the buserelin acetate: DM-beta-CyD system showed a 1:1 stoichiometry of the complex. Therefore, the complexation should be initiated by the inclusion of one of the three binding sites on the buserelin molecule into DM-beta-CyD, which may in turn prevent the further access of the second cyclodextrin to the other binding sites, probably due to steric hindrance and/or conformational changes of the peptide. These structural features of the complex would account for the stabilizing effect of DM-beta-CyD on the enzymatic degradation of buserelin acetate.

Buserelin↗
PubMed1997

Varying effects of cyclodextrin derivatives on aggregation and thermal behavior of insulin in aqueous solution.

Maltosyl-beta-cyclodextrin (G2-beta-CyD) suppressed the aggregation of insulin in neutral solution, while the sulfate of beta-CyD (S-beta-CyD) accelerated the aggregation. On the other hand, the sulfobutyl ether of beta-CyD (SBE-beta-CyD) showed varying effects on insulin aggregation, depending on the degree of substitution of the sulfobutyl group: i.e., the inhibition at relatively low substitution and acceleration at higher substitution. Differential scanning calorimetric studies indicate that the self-association of insulin stabilized the native conformation of the peptide, as indicated by an increase in the mean unfolding temperature (Tm). G2-beta-CyD and SBE-beta-CyD decreased the Tm value of insulin oligomers, while S-beta-CyD increased the Tm value. 1H-Nuclear magnetic resonance spectroscopic studies suggest that G2-beta-CyD includes accessible hydrophobic side chains of insulin within the CyD cavity, and hence perturbs the intermolecular hydrophobic contacts between aromatic side chains across the monomer-monomer interfaces. By contrast, the electrostatic interaction between the positive charges of insulin and the concentrated negative charges of the sulfate and sulfonate groups of the anionic beta-CyDs seems to be more of a factor than the inclusion effects. These results suggest proper use of the CyD derivatives could be effective in designing rapid or long-acting insulin preparations.

Animals↗
PubMed1997

[Investigation of complications of bronchial artery embolization using superselective catheter system and platinum coil-major complications as vascular detachment].

We have performed bronchial artery embolization (BAE) in patients with hemoptysis using a superselective catheter system and a permanent-emboli coil. We performed an investigation because major complications were observed. Of a total of 57 BAE using this system, 7 cases of major complications as detachment of the large vessel were found. Although BAE using this system is effective because permanent emboli can be selectively in-dwelled in abnormally developing vessels, detachment of vessels were developed in 7 cases. They are found more frequently for embolization of the left bronchial artery and full attention should be paid to this phenomenon when performing this surgery.

Adult↗
PubMed1997

Mechanical impedance of layered tissue.

The human body is a medium which consists of various tissues such as skin, fat, muscle and bone. Each of the tissues has their own biomechanical properties. We have measured biomechanical impedances by applying a random vibration (30-1000 Hz) to the layered model of human tissues to study the occurring mechanism of impedances measured at the skin surface. The data showed that the top tissue layer and the underlying layer both contribute to the impedance depending on the thickness of the top layer. The contribution of the underlying layer was clearer over the frequency range from 30 to 400 Hz. Quantitatively we found the following: The impedance measured at the surface was roughly expressed as the model which is connected in series by the impedances of the top and underlying tissues. The contribution of the underlying tissue decreased according to the increase of the thickness of the top tissue, and disappeared over a certain thickness (18 mm in this paper).

Adipose Tissue↗
PubMed1996

Time courses of changes in cerebral blood flow and blood-brain barrier integrity by focal proton radiation in the rat.

In order to know the pathophysiological mechanisms underlying radiation brain injury, cerebral blood flow and blood-brain barrier integrity were studied using N-isopropyl-p-[123l]iodoamphetamine (IMP) and [14C]-alpha-aminoisobutyric acid (AIB), respectively, in the rat focal proton radiation model (a single dose of 30 or 60 Gy radiation with 70 MeV proton beams). One, 2, 4, and 5.5 months after irradiation, [123l]IMP and [14C]AIB were intravenously injected and uptake of IMP and AIB in the cerebral cortex, striatum, hippocampus, and thalamus was measured. Significant decreases in IMP uptake were observed in the cerebral cortex and thalamus of the irradiated side at 4 and 5.5 months after 60 Gy irradiation; the effects at 5.5 months were more prominent than those at 4 months. AIB uptake markedly increased in all the brain regions of the irradiated side at 5.5 months after 60 Gy irradiation, and at 4 months, only in the hippocampus. The results suggest that there are dose- and time-dependent responses in radiation effects and regional differences in tissue vulnerability to radiation. Proton focal radiation model appears to be a useful model for studies of radiation brain injury in small animals such as rats.

Aminoisobutyric Acids↗
PubMed1996

Fragmented platinum microcoils as embolization material. Preliminary evaluation in vivo.

PURPOSE: To evaluate the feasibility of using fragmented microcoils as embolization material. MATERIAL AND METHODS: Fragmented microcoil particles were produced from a coil of 0.42-mm platinum guide wire. The diameter of the particles was 420 mu and the length was 450-800 mu. To prevent the catheters from being obstructed by the particles, a core shaft wire was passed through the channels of the particles and a hollow plunger was used to release particles from the catheter. Forty particles were introduced into 4 kidneys in 4 adult dogs following transfemoral catheterization and systemic heparinization. Renal arteriography was performed immediately, and at 60 min, and at 3 weeks after embolization. RESULTS: All particles were successfully introduced into the periphery of the kidneys, and caused occlusion within 3 weeks of embolization. CONCLUSION: Fragmented platinum microcoil particles can be used as embolization material to avoid catheter obstruction.

Animals↗
PubMed1996

Combination effects of alpha-cyclodextrin and xanthan gum on rectal absorption and metabolism of morphine from hollow-type suppositories in rabbits.

Pharmacokinetics of morphine and its glucuronides in plasma were studied after rectal administration of hollow-type oleaginous suppositories containing kneading mixtures of morphine hydrochloride, alpha-cyclodextrin, and/or xanthan gum in rabbits. In combination with xanthan gum, alpha-cyclodextrin reduced the first-pass metabolism of morphine in the rectal mucosa and by the liver and improved the apparent rectal bioavailability of the opioid about 4 fold. In vitro permeation studies using an isolated rectal mucosal preparation of rabbits revealed that alpha-cyclodextrin increased the transepithelial conductance and facilitated the transport of morphine through the rectal mucosa. Furthermore, alpha-cyclodextrin facilitated its own mucosal permeation and reduced the glucuronidation of morphine during the passage through the rectal mucosa, probably through restricting the formation of a catalytic complex of morphine with glucuronyltransferases, rather than because of the enzyme saturation. The present data suggest that alpha-cyclodextrin in combination with xanthan gum is particularly effective in improving the rectal bioavailability of morphine from hollow-type suppositories.

Analgesics, Opioid↗
PubMed1996

Possible enhancing mechanism of the cutaneous permeation of 4-biphenylylacetic acid by beta-cyclodextrin derivatives in hydrophilic ointment.

The enhancing effects of heptakis(2,6-di-O-methyl)-beta-cyclodextrin (DM-beta-CyD) and 2-hydroxypropyl-beta-cyclodextrin (HP-beta-CyD) on the percutaneous absorption of 4-biphenylylacetic acid (BPAA), a nonsteroidal anti-inflammatory drug, in hydrophilic ointment were studied and compared with the parent beta-cyclodextrin (beta-CyD). 13C-NMR measurements suggested that the biphenyl group of BPAA is preferably included within the cavity of three beta-CyDs. The three beta-CyDs remarkably enhanced the release of BPAA from the hydrophilic ointment base and the in vitro cutaneous permeation, depending on the increase in solubility of BPAA in the ointment base. Pretreatment of the ointment containing DM-beta-CyD or HP-beta-CyD onto the isolated skin of hairless mice, however, provided no effects on the skin permeation of BPAA. When propylene glycol was used as a vehicle, both the release rate and cutaneous permeation parameters showed no appreciable difference between BPAA alone and its HP-beta-CyD complex, because the solubilities of BPAA and its HP-beta-CyD complex were almost comparable in the vehicle. The present results suggested that the enhancing effect of beta-CyDs on the percutaneous absorption of BPAA can be mainly ascribed to an increase in the solubility of BPAA in the hydrophilic ointment.

Animals↗
PubMed1996

A novel 1 beta-methylcarbapenem antibiotic, S-4661. Synthesis and structure-activity relationships of 2-(5-substituted pyrrolidin-3-ylthio)-1 beta-methylcarbapenems.

The synthesis and biological activity of (1R,5S,6S)-2-[(3S,5S)-5-substituted pyrrolidin-3-ylthio]-6-[(1R)-1-hydroxyethyl]-1- methylcarbapen-2-em-3-carboxylic acids are described. These compounds exhibit potent antibacterial activity against a wide range of both Gram-positive and Gram-negative bacteria including Pseudomonas aeruginosa. Of these new carbapenems, (1R,5S,6S)-2-[(3S,5S)-5-sulfamoylaminomethyl pyrrolidin-3-ylthio]-6-[(1R)-1-hydroxyethyl]-1-methylcarb apen- 2-em-3-carboxyli c acid (S-4661) showed the most potent and well balanced activity and was selected as a candidate for further evaluation.

Anti-Bacterial Agents↗
PubMed1996

Brain acetylcholinesterase activity: validation of a PET tracer in a rat model of Alzheimer's disease.

UNLABELLED: We developed three radioactive acetylcholine analogs--N[14C]methyl-4-piperidyl acetate ([14C]MP4A), propionate ([14C]MP4P) and isobutyrate ([14C]MP4IB)--as radiotracers for measuring brain acetylcholinesterase (AchE) activity in vivo. The principle of our method is that the lipophilic analog diffuses into the brain where it is metabolized by AchE to produce a hydrophilic metabolite, which is trapped at the site of its production. The purpose of this study was to examine whether the tracers would have the sensitivity needed for early diagnosis of Alzheimer' disease using rats with a unilateral lesion in the nucleus basalis magnocellularis (NBM), an animal model of the cholinergic deficit in Alzheimer's disease. METHODS: Rats with a unilateral NBM lesion were prepared, and the N[14C]methyl-4-piperidyl esters and N-Isopropyl-p-[123I]iodoamphetamine([123I]IMP were injected intravenously 30 and 2 min, respectively, before the rats were killed. Uptake of 14C and 123I and AchE activity in the lesioned and unlesioned (control) sides of the cortex were measured simultaneously. RESULTS: The NBM lesion showed reduced cortical AchE activity by 30%-50%, with no side-to-side differences in [123I]MP uptake. Autoradiographic studies showed that uptake of 14C from [14C]MP4A and [14C]MP4P was significantly lower in the lesioned than unlesioned side of the cortex, which agreed well with the AchE histochemical staining patterns. Tissue dissection studies showed different uptake changes for the three compounds when AchE activity in the lesioned side of the cortex was reduced by 50%: 14C uptake from [14C]MP4P, [14C]MP4A and [14C]MP4IB was reduced by 27%, 21% and 7.3%, respectively. Theoretical analysis of the observed sensitivities of the tracers in relation to their in vitro enzymatic properties indicated that tracer sensitivity was highly dependent on the enzymatic hydrolysis rate of the tracer. CONCLUSION: The [14C]MP4A and [14C]MP4P esters had sufficient sensitivity to enable AchE activity changes in the rat cortex of less than 50% to be detected, indicating that the present method is applicable to PET diagnosis of Alzheimer's disease.

Acetates↗
PubMed1996

[Peri- and postoperative courses in patients undergoing concomitant cardiac and pulmonary operations].

We studied peri- and postoperative courses in patients undergoing concomitant cardiac and pulmonary operations (CCPO), which included pulmonary resection and coronary artery bypass grafting (CABG). Of eight patients who had lung cancer and ischemic heart disease (IHD), six underwent CCPO and two patients first had percutaneous transluminal coronary angioplasty (PTCA) followed by lung surgery at an interval after the first procedure. Twelve patients with lung cancer who underwent only pulmonary surgery and 13 patients with IHD who were treated with CABG were studied as controls. We compared peri- and postoperative characteristics among these groups of patient. Operating time, bleeding volume during surgery, amount of drainage discharge within 24 hours after the operation, and ICU days were significantly increased in the CCPO group in comparison with the two control groups. In the CCPO group, mechanical ventilatory support time and administration days after the operation were significantly increased in comparison with the lung operation group, but not in comparison with CABG group. The two patients who sequentially underwent PTCA and lung surgery had postoperative courses similar to the CCPO patients. All CCPO patients were ambulatory upon discharge. None of the CCPO patients died from postoperative complications involving the respiratory tract or the circulatory system. Our data suggest that CCPO is available for patients with both heart and lung diseases when complications can be avoided by appropriate management, although these procedures are extremely invasive. We believe that CCPO should be attempted in patients with definite indications for such a procedure.

Aged↗