Effect of multiphoton ionization on high-order harmonic generation and propagation in rare gases with subpicosecond laser pulses.
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Journal Article↗
Biomedical subjects
K Miyazaki
Publications and source records attributed to K Miyazaki.
Enantioselective pharmacokinetics of homochlorcyclizine: disposition of (+)- and (-)-homochlorcyclizine after intravenous and oral administration of racemic homochlorcyclizine to rats.
Concentrations of homochlorcyclizine enantiomers in blood, urine, and tissues of the liver, lung, kidney, brain, heart, spleen, intestine and stomach of rats after drug administration were determined by high-performance liquid chromatography on a chiral stationary phase. After intravenous administration (10 mg kg-1), homochlorcyclizine was rapidly distributed in many tissues, with the highest concentration in lung. No differences were found between enantiomers in blood concentrations. After oral administration (50 mg kg-1), the concentrations of the (+)-isomer in nearly all tissues were higher than those of the (-)-isomer. The AUC0-infinity values of the (+)- and (-)-isomers differed significantly. The absorption of racemic homochlorcyclizine from rat small intestine was not enantioselective. These results suggested that the different concentrations between enantiomers after oral administration were not caused by enantioselective absorption or distribution but rather by preferential first-pass metabolism of the (-)-isomer in the liver. The enantioselectivity of metabolism was also demonstrated by in-vitro experiments.
Administration, Oral↗
The stimulative effect of diffusion potential on enoxacin uptake across rat intestinal brush-border membranes.
Evidence of a membrane potential dependence for enoxacin uptake by rat intestinal brush-border membrane vesicles has been found. The transient overshooting uptake of enoxacin disappeared in the voltage-clamped brush-border membrane vesicles in the presence of an outward H(+)-gradient. Momentary dissipation of the H(+)-gradient itself by carbonyl cyanide p-(trifluoromethoxy)phenylhydrazone (FCCP) did not affect the uptake of enoxacin. In contrast, enoxacin uptake was depressed by an interior positive K(+)-diffusion potential induced by valinomycin. Furthermore, not only the outward H(+)-gradient but also an inward Cl(-)-gradient caused a stimulating effect on enoxacin uptake, and the stimulation by the Cl(-)-gradient was dissipated by using voltage-clamped membrane vesicles. These results indicate that enoxacin transportation across the brush-border membrane is dependent on the ionic diffusion potential. On the other hand, neither Gly-Gly nor guanidine had any effect on enoxacin uptake by the membrane vesicles in the presence of an inward (for Gly-Gly) or outward (for guanidine) H(+)-gradient as a driving force for each transport system. Therefore, it seems that enoxacin transport through the intestinal epithelia does not participate in the carrier-mediated transport systems for Gly-Gly and guanidine.
Animals↗
The inhibitory effects of cephalosporin and dipeptide on ceftibuten uptake by human and rat intestinal brush-border membrane vesicles.
The types of inhibitory effects caused by compound V (an analogue of ceftibuten) and alanylproline (dipeptide) on the uptake of ceftibuten by brush-border membrane vesicles (BBMV) prepared from human and rat small intestine were analysed. In the presence of an inward H(+)-gradient, the initial uptake rate of ceftibuten by both human and rat intestinal BBMV was concentration-dependent with apparent Km and Vmax values of 0.35 mM and 2.052 nmol (mg protein)-1 min-1 for human BBMV, and 0.50 mM and 3.056 nmol (mg protein)-1 min-1 for rat BBMV, respectively. For both human and rat BBMV, kinetic analysis by Dixon and Lineweaver-Burk plots demonstrated that the uptake of ceftibuten was competitively inhibited by compound V, whereas inhibition by alanylproline was noncompetitive or partially competitive. These results suggest that there is a stereospecific transport system which is common to ceftibuten and compound V, and that this system is not identical to the carrier system for the dipeptide, alanylproline.
Animals↗
Value of phase-shift gradient-echo MR imaging in the differentiation of pelvic lesions with high signal intensity at T1-weighted imaging.
PURPOSE: To assess the value of phase-shift gradient-echo magnetic resonance (MR) imaging with the fast low-angle shot (FLASH) technique in the differentiation of hemorrhagic tumors and teratomas. MATERIALS AND METHODS: T1- and T2-weighted spin-echo imaging and phase-shift MR imaging were performed in 60 patients. On T1-weighted images, the signal intensity of lesions was compared with that of intraperitoneal fat. Findings at MR imaging were compared with the surgical findings. The diagnostic performance of each pulse sequence was analyzed with receiver operating characteristic curves. RESULTS: Sixty high-signal-intensity lesions were identified in 45 patients at T1-weighted imaging. Hemorrhagic lesions and teratomas had similar signal intensities on both T1- and T2-weighted images. Lesions were detected more decisively with FLASH imaging than with T1- and T2-weighted imaging. CONCLUSIONS: Phase-shift gradient-echo imaging is a readily available method for the differential diagnosis of lesions with high signal intensity at T1-weighted MR imaging.
Adolescent↗
The relationship between cure depth and transmission coefficient of visible-light-activated resin composites.
The relationships between the transmission coefficient and the cure depth were evaluated on eight commercially available light-activated resin composites. The determination of transmission coefficient was carried out by the use of a radiometer for various shades of the resin composites. The transmission coefficient, ranging from 0.042 to 0.263, was dependent upon the shade of the resin. There was a good correlation between the transmission coefficient and the cure depth for different shades for each resin composite, except for one hybrid resin composite (P-50). The microfilled resin composite showed transmission coefficient and cure depth lower than those of the hybrid and small-particle-filled resin composites.
Analysis of Variance↗
Effect of first-pass metabolism on enantioselective pharmacokinetics after oral administration of (+)-, (-)- and racemic homochlorcyclizine to rats.
The enantioselective relationship between the pharmacokinetics and hepatic metabolism of homochlorcyclizine hydrochloride (HCZ) was investigated using rats. There were no significant differences in blood concentrations between the three forms after intravenous administration (5 mg/kg) of (+)-, (-)- and racemic HCZ. On the other hand, there were significant differences in the pharmacokinetics between (-)- and (+)-HCZ and between (-)- and racemic HCZ after oral administration (50 mg/kg) of these three forms. The Cmax and AUC0-infinity of (-)-HCZ were lower than those of (+)-isomer and racemate, and its CLo was clearly higher than the others. The (+)-isomer and racemate showed no significant differences in their pharmacokinetic parameters. At a lower dose (10 mg/kg), however, no enantiomeric differences were found in the pharmacokinetic parameters of (+)- and (-)-HCZ. Also examined was the cytochrome p-450-dependent-oxidative metabolism of (+)-, (-)- and racemic HCZ in vitro using rat liver 9000 x g supernatant fraction. The in vitro metabolism of (-)-HCZ was extremely fast, compared with those of the (+)-isomer and the racemate. The Vmax in vitro showed a good correlation with the CLo in vivo after oral administration (50 mg/kg) of all three forms of HCZ. In vitro study of enantiomeric inhibition of the metabolism showed that (+)-HCZ was a competitive inhibitor of (-)-HCZ metabolism, with a Ki of 6.96 microM. (-)-HCZ was also a competitive inhibitor of (+)-HCZ metabolism, with a Ki of 20.4 microM.(ABSTRACT TRUNCATED AT 250 WORDS)
Administration, Oral↗
Tyrosinase inhibitors from crude drugs.
Various crude drugs were examined for their tyrosinase inhibitory activity. Marked activity was observed in Chouji and Yakuchi extracts and the active substances in these extracts were identified as eugenol and yakuchinone A, respectively. Other vanillyl compounds such as ferulic acid, curcumin and yakuchinone B also had higher activities than eugenol or yakuchinone A and inhibited the enzyme competitively. The presence of the hydroxyl group at the 4 position of the aromatic ring of the cinnamoyl moiety and the alpha,beta-unsaturated carbonyl conjugated with an aromatic ring in these substances may play important roles in the competitive inhibition of tyrosinase.
Benzaldehydes↗
[Effect of Enterued administration on the intestinal absorption of orally active cefem antibiotics].
The effect of simultaneous administration of Enterued, an elemental diet, which is composed of oligopeptides (egg white hydrolyzate), on the orally active cefems was investigated. Ceftibuten (CETB) administered together with Enterued to man was excreted slower in the urine. AUC from the plasma concentrations of CETB after the oral administration with Enterued was markedly decreased compared to that without Enterued in rat. In contrast, neither urinary excretion of cephalexin (CEX) in man nor the AUC from the plasma profile of CEX in rat was changed by Enterued. Furthermore, the disappearance, tissue accumulation, net absorption of CETB from the rat jejunal loop were significantly inhibited by Enterued. However, the net absorption of CEX has no alternation in the presence of Enterued, although the apparent disappearance decreased on the basis of the diminishment of tissue accumulation. Additionally, Hepan ED, which is an elementary diet composed of amino acids, and the mineral solution containing neither peptides nor vitamins have also exhibited the decreasing effect on the CETB absorption behaviour. These results suggested that the inhibitory effects of Enterued on the absorption of these antibiotics were not due to the inhibition of peptide-transport systems.
Administration, Oral↗
[Cyclosporine level in blood as monitored by area-under-the-curve (AUC). III. The influence of absorption phase after orally dosing].
The influence of the absorption phase (the time of maximum blood concentration; Tmax) on the pharmacokinetics of cyclosporine (CYA) in the steady state after oral administration was studied in 26 renal transplant recipients. The patients were divided into three absorption phase groups with the Tmax times as follows, group A (n = 26); OH < or = Tmax < 3 h, group B (n = 6); 3 h < or = Tmax < 6 h and group C (n = 11); 6 h < or = Tmax < or = 12 h. CYA (dose; 1.6-15.0 mg/kg/d) was administered orally to all 26 patients (10-52 years, 33.1-74.2 kg) every 12 h. The blood specimens used in this study were collected just before administration (0 h) in the morning and at intervals of 1, 2, 3, 6, 8 and 12 h after administration. The whole blood CYA levels were measured by high-performance liquid chromatography (HPLC) or by fluorescence polarization immunoassay (FPIA) based on a specific monoclonal antibody. There were no significant differences between the three groups in terms of the dosage (mg/kg/d) and area-under-the-curve (AUC). The trough levels (0, 12 h) correlated well to the AUC only in group A (r = 0.842-0.907, p < 0.001). The morning trough levels (0 h) were significantly higher than the night trough levels (12 h) in groups A and B (p < 0.05-0.01).(ABSTRACT TRUNCATED AT 250 WORDS)
Administration, Oral↗
Transcatheter arterial embolization of obstetric and gynaecological bleeding: efficacy and clinical outcome.
32 patients with uncontrollable genital bleeding resulting from postpartum haemorrhage (n = 15) or malignant neoplasms (n = 17) were treated by arterial embolization therapy on an emergency basis. The 15 patients with postpartum haemorrhage responded dramatically to treatment by embolization. Follow-up computed tomography or magnetic resonance studies in 12 cases showed haematomas in the pelvic extraperitoneal space, but most then reduced in size or disappeared spontaneously. In two patients with large haematomas, laparotomy was required. No serious complications developed and normal menstruation resumed in the women who did not undergo hysterectomy. In the 17 patients with malignant neoplasms, bleeding was temporally controlled in all, but recurred in seven and required re-embolization in three. One patient experienced slight numbness of the leg and another had a skin ulcer. All patients underwent subsequent treatment including radiation therapy (n = 10), operation (n = 5) or chemotherapy (n = 2). We conclude that arterial embolization has significant merits in the management of patients with uncontrollable genital bleeding.
Adult↗
Adenoma malignum: MR appearances mimicking nabothian cysts.
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Adenocarcinoma↗
Mature cystic teratomas of the ovary without fat in the cystic cavity: MR features in 12 cases.
OBJECTIVE: The diagnosis of mature cystic teratoma may be overlooked in the small number of cases that do not contain fat in the lumen of the cyst. The purpose of this study was to evaluate the MR appearance of mature cystic teratomas containing little or no fat and to determine the value of gradient-echo MR imaging for detection of small amounts of fat. MATERIALS AND METHODS: In a review of pathologic specimens of 78 mature cystic teratomas, we found 12 tumors without fatty fluid (sebum) in their cystic cavity. Histologically, a small amount of fat was present in the wall of the cyst in each case. We retrospectively reviewed MR images of these tumors. In seven tumors with small amounts of hyperintense tissue on T1-weighted MR images, opposed-phase and in-phase gradient-echo MR images were obtained in order to verify the presence of fat. RESULTS: All 12 lesions were hypointense on T1-weighted MR images and markedly hyperintense on T2-weighted images, indicating that the cystic cavity contained aqueous fluid. Fatty tissue was not identified in the lumen or wall of the cyst on MR images in five of the 12 tumors. In seven tumors, MR images showed small hyperintense areas in the walls of the cysts. These hyperintense signals were canceled on opposed-phase gradient-echo images. Characteristic MR findings for mature cystic teratoma, such as reversed chemical-shift artifact, gravity-dependent layering, or dermoid plug, were not observed in any of the lesions. CONCLUSION: MR images in some cases of mature cystic teratomas may show aqueous fluid within the lumen of the cyst. In such cases, detection of fat in the cyst wall, especially with gradient-echo MR imaging, may help to establish the diagnosis.
Adipose Tissue↗
Thermal- and photo-polymerization of (meth) acrylates containing a spiro ortho ester moiety and the properties of poly[(meth)acrylate]s.
The syntheses and polymerizations of acrylate (ASOE) and methacrylate (MASOE) containing spiro ortho ester moieties were carried out and the properties of the polymers obtained were investigated. The ring-opening reaction of the spiro ortho ester groups proceeded well during heat polymerization (HC) with the ionic initiators (BSS and HPSS). However, a small amount of unreacted carbon-carbon double bond was observed in the polymers obtained. Not only vinyl polymerization but also a small amount of ring-opening reaction took place during polymerization with radical initiators (BPO, AIBN, DTB and CQ). The poly-(MASOE)s obtained by HC with BSS, BSS/AIBN and BSS/BPO were plastic like polymers. Low volume shrinkage was observed during HC and UVLC of ASOE and MASOE with ionic initiators. These shrinkages were smaller than those of conventional methacrylate.
Acrylates↗
[Hepatic arterial infusion therapy in a patient with multiple hepatic metastases from gastric cancer].
A patient with multiple hepatic metastases (H3) from advanced gastric cancer was treated with pre- and post-operative arterial infusion therapy. A Port-A-Cath was cannulated into the gastroduodenal artery after total gastrectomy. Repeated arterial infusions were performed monthly in the outpatient ward. The volume of hepatic tumors was remarkably decreased to 12% of the pretreatment level. The patient has been alive for 15 months after the operation without any complaint. Arterial infusion chemotherapy through implantable reservoir is useful for the treatment of unresectable hepatic metastasis without decreasing the quality of life.
Chemotherapy, Adjuvant↗
[A comparative study on the serum and tissue 5-FU concentrations in patients with hepatocellular carcinoma after preoperative oral administration of UFT and 5'-DFUR].
UFT or 5'-DFUR was orally administered to the patients with hepatocellular carcinoma preoperatively and the concentrations of these drugs and 5-FU in the serum, liver tissue and cancer tissue obtained at the time of operation were measured. The unchanged 5'-DFUR was not detected in any of these samples. The concentration of 5-FU in cancer tissue was significantly higher in UFT treated group (0.409 microgram/g) than that in 5'-DFUR group (0.040 microgram/g). However, the 5-FU levels in the serum and noncancerous liver tissue were also higher than those in the patients with other organ cancers. Although UFT is a useful drug for the adjuvant chemotherapy of hepatocellular carcinoma, the dose was considered to be minimized to avoid the side effects since the activity of drug-metabolizing enzymes may be decreased in hepatocellular carcinoma complicated with liver cirrhosis.
Administration, Oral↗
In vitro release of vasoactive intestinal polypeptide and pancreatic polypeptide from human VIPoma cells and its inhibition by somatostatin analogue (SMS 201-995).
BACKGROUND: The purpose of the present study was to determine whether vasoactive intestinal polypeptide (VIP) is released from the tumor cells of VIPoma and if so then to attempt to show how its release is regulated by cultured human VIPoma cells. METHODS: A resected specimen of a pancreatic tumor from a patient with watery diarrhea, hypokalemia, and achrohydria syndrome was examined. The dissociated cells were obtained by collagenase digestion of the tumor tissue and were cultured in vitro. RESULTS: The extraction of tumor cells disclosed that the cells contained VIP and pancreatic polypeptide (PP). Neither insulin, glucagon, somatostatin nor pancreastatin was detected. Immunohistochemically, 40% to 60% of the cells in the tumor stained positively for VIP and 1% to 5% stained positively for PP. The dissociated cells became reaggregated in the culture (50 to 300 microns) and could be maintained in vitro. Incubation experiments revealed a simultaneous in vitro release of VIP and PP with a significant increase by either carbachol or phorbol myristate acetate but not by theophylline or caerulein. Atropine completely abolished the stimulatory effects of carbachol on VIP and PP release. Octreotide (somatostatin analogue [SMS 201-995]) significantly inhibited the carbachol and phorbol myristate acetate-stimulated VIP and PP release. CONCLUSIONS: These findings show the in vitro release of VIP and PP from the VIPoma cells and also provide evidence for the direct inhibitory effect of somatostatin analogue on both the VIP and PP release from the tumor cells.
Adult↗