Biomedical subjects

Minoru Suzuki

Publications and source records attributed to Minoru Suzuki.

At least 19 recordsLinked to original sources

PubMed2006

The potential of transferrin-pendant-type polyethyleneglycol liposomes encapsulating decahydrodecaborate-(10)B (GB-10) as (10)B-carriers for boron neutron capture therapy.

PURPOSE: To evaluate GB-10-encapsulating transferrin (TF)-pendant-type polyethyleneglycol (PEG) liposomes as tumor-targeting (10)B-carriers for boron neutron capture therapy. METHODS AND MATERIALS: A free mercaptoundecahydrododecaborate-(10)B (BSH) or decahydrodecaborate-(10)B (GB-10) solution, bare liposomes, PEG liposomes, or TF-PEG liposomes were injected into SCC VII tumor-bearing mice, and (10)B concentrations in the tumors and normal tissues were measured by gamma-ray spectrometry. Meanwhile, tumor-bearing mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all intratumor proliferating cells, then injected with these (10)B-carriers containing BSH or GB-10 in the same manner. Right after thermal neutron irradiation, the response of quiescent (Q) cells was assessed in terms of the micronucleus frequency using immunofluorescence staining for BrdU. The frequency in the total tumor cells was determined from the BrdU nontreated tumors. RESULTS: Transferrin-PEG liposomes showed a prolonged retention in blood circulation, low uptake by reticuloendothelial system, and the most enhanced accumulation of (10)B in solid tumors. In general, the enhancing effects were significantly greater in total cells than Q cells. In both cells, the enhancing effects of GB-10-containing (10)B-carriers were significantly greater than BSH-containing (10)B-carriers, whether loaded in free solution or liposomes. In both cells, whether BSH or GB-10 was employed, the greatest enhancing effect was observed with TF-PEG liposomes followed in decreasing order by PEG liposomes, bare liposomes, and free BSH or GB-10 solution. In Q cells, the decrease was remarkable between PEG and bare liposomes. CONCLUSIONS: In terms of biodistribution characteristics and tumor cell-killing effect as a whole, including Q cells, GB-10 TF-PEG liposomes were regarded as promising (10)B-carriers.

Animals↗

PubMed2006

Impact of intra-arterial administration of boron compounds on dose-volume histograms in boron neutron capture therapy for recurrent head-and-neck tumors.

PURPOSE: To analyze the dose-volume histogram (DVH) of head-and-neck tumors treated with boron neutron capture therapy (BNCT) and to determine the advantage of the intra-arterial (IA) route over the intravenous (IV) route as a drug delivery system for BNCT. METHODS AND MATERIALS: Fifteen BNCTs for 12 patients with recurrent head-and-neck tumors were included in the present study. Eight irradiations were done after IV administration of boronophenylalanine and seven after IA administration. The maximal, mean, and minimal doses given to the gross tumor volume were assessed using a BNCT planning system. RESULTS: The results are reported as median values with the interquartile range. In the IA group, the maximal, mean, and minimal dose given to the gross tumor volume was 68.7 Gy-Eq (range, 38.8-79.9), 45.0 Gy-Eq (range, 25.1-51.0), and 13.8 Gy-Eq (range, 4.8-25.3), respectively. In the IV group, the maximal, mean, and minimal dose given to the gross tumor volume was 24.2 Gy-Eq (range, 21.5-29.9), 16.4 Gy-Eq (range, 14.5-20.2), and 7.8 Gy-Eq (range, 6.8-9.5), respectively. Within 1-3 months after BNCT, the responses were assessed. Of the 6 patients in the IV group, 2 had a partial response, 3 no change, and 1 had progressive disease. Of 4 patients in the IA group, 1 achieved a complete response and 3 a partial response. CONCLUSION: Intra-arterial administration of boronophenylalanine is a promising drug delivery system for head-and-neck BNCT.

Adult↗

PubMed2006

Feasibility of boron neutron capture therapy (BNCT) for malignant pleural mesothelioma from a viewpoint of dose distribution analysis.

PURPOSE: To investigate the feasibility of boron neutron capture therapy (BNCT) for malignant pleural mesothelioma (MPM) from a viewpoint of dose distribution analysis using Simulation Environment for Radiotherapy Applications (SERA), a currently available BNCT treatment planning system. METHODS AND MATERIALS: The BNCT treatment plans were constructed for 3 patients with MPM using the SERA system, with 2 opposed anterior-posterior beams. The (10)B concentrations in the tumor and normal lung in this study were assumed to be 84 and 24 ppm, respectively, and were derived from data observed in clinical trials. The maximum, mean, and minimum doses to the tumors and the normal lung were assessed for each plan. The doses delivered to 5% and 95% of the tumor volume, D(05) and D(95), were adopted as the representative dose for the maximum and minimum dose, respectively. RESULTS: When the D(05) to the normal ipsilateral lung was 5 Gy-Eq, the D(95) and mean doses delivered to the normal lung were 2.2-3.6 and 3.5-4.2 Gy-Eq, respectively. The mean doses delivered to the tumors were 22.4-27.2 Gy-Eq. The D(05) and D(95) doses to the tumors were 9.6-15.0 and 31.5-39.5 Gy-Eq, respectively. CONCLUSIONS: From a viewpoint of the dose-distribution analysis, BNCT has the possibility to be a promising treatment for MPM patients who are inoperable because of age and other medical illnesses.

Boron Compounds↗

PubMed2006

Dependency of the effect of a vascular disrupting agent on sensitivity to tirapazamine and gamma-ray irradiation upon the timing of its administration and tumor size, with reference to the effect on intratumor quiescent cells.

PURPOSE: The effect of vascular disrupting agent ZD6126 with time on the sensitivity to the hypoxic cytotoxin tirapazamine (TPZ) and gamma-rays was examined in large and small solid tumors. METHODS: Mice bearing SCC VII tumors 1 or 1.5 cm in diameter received 5-bromo-2'-deoxyuridine (BrdU) continuously to label all proliferating (P) cells, followed by injection with or without ZD6126. In the absence of ZD6126, or 1 or 24 h following ZD6126 injection, the response to TPZ or gamma-ray irradiation in quiescent (Q) cells was assessed in terms of induced micronucleus (MN) frequency using immunofluorescence staining for BrdU. The MN frequency in the total cell population was determined from the tumors not pretreated with BrdU. Another group of tumor-bearing mice received a series of test doses of gamma-rays while alive or after tumor clamping to obtain hypoxic fractions (HFs) in the tumors. RESULTS: One hour after ZD6126 injection, both small and large tumors showed lower and higher sensitivity, and 24 h after, higher and lower sensitivity, to gamma-rays and TPZ, respectively, than the tumors not treated with ZD6126. Further, they showed larger and smaller HFs 1 and 24 h after ZD6126 injection, respectively. Without ZD6126 and 1 h after injection, small tumors were more sensitive to gamma-rays and less sensitive to TPZ than large tumors, probably due to the smaller HFs than large tumors. In contrast, 24 h after the injection, these differences in sensitivity and the HF between small and large tumors were reversed. The changes in sensitivity and the size of the HF were more marked in the total cell population than in Q cells. CONCLUSIONS: Following ZD6126 treatment, in terms of tumor control, especially large tumors and total tumor cell population, administering TPZ 1 h later and gamma-ray irradiation 24 h later were effective. Intratumor physiologic factors such as the size of the HF, depending on the time after ZD6126 injection, have to be taken into account when combining another treatment with ZD6126.

Angiogenesis Inhibitors↗

PubMed2006

Identification and characterization of an increased glycoprotein in aging: age-associated translocation of cathepsin D.

We found that 14 N-glycosylated proteins were accumulated in the rat cerebral cortex cytosolic fraction in the aging process by a comparative study with two-dimensional gel electrophoresis and concanavalin A staining. All proteins had high mannose and/or hybrid-type N-glycans, as indicated by the fact that they were sensitive to endoglycosidase H digestion. Three of these cytosolic glycoproteins were identified as cathepsin D, a lysosomal protease, by tryptic digestion and nano liquid chromatography electrospray ionization quadrupole time of flight mass spectrometry. The increase of cytosolic cathepsin D during aging was not due to lysosomal membrane disruption, as shown by the fact that the activities of beta-hexosaminidase and beta-glucuronidase, other lysosomal enzymes, did not increase in the cytosolic fraction. Although the total amount of cathepsin D increased during aging, the amount of cathepsin D in the microsomal fraction did not change, indicating a selective increase of cytosolic cathepsin D. This phenomenon was also observed in the hippocampus, cerebellum, kidney, liver, and spleen. Based on these results, we propose that cytosolic cathepsin D is a new biomarker of aging.

Aging↗

PubMed2006

Association of a mutation in TRPV3 with defective hair growth in rodents.

DS-Nh mice and WBN/Kob-Ht rats are spontaneous hairless mutant rodent strains. These animals develop spontaneous dermatitis under normal conditions. The non-hair Nh and Ht phenotypes are inherited in an autosomal dominant fashion, and the Nh mutation possesses a high potency for penetration. We previously reported that genes involved in dermatitis and hairlessness did not segregate from each other. Here, we carried out genetic analysis to identify the genes responsible for these hairless mutations. An amino-acid substitution at the same position in one gene was detected in DS-Nh mice and WBN/Kob-Ht rats: Gly573 to Ser (Nh mutation) or Gly573 to Cys (Ht mutation), located in the transient receptor potential (TRP) cation channel subfamily V member 3 (TRPV3) gene. Mutated TRPV3 was expressed in skin keratinocytes of DS-Nh mice. Histopathological analyses revealed that mast cells in skin lesions were increased in both rodents compared to their age-matched parent strains, and that this may partially be due to hairlessness and dermatitis. We concluded that TRPV3 was the gene responsible for Nh and Ht mutations, and that mutation in TRPV3 possibly correlated with increased mast cell numbers.

Alopecia↗

PubMed2006

Regulation of insect steroid hormone biosynthesis by innervating peptidergic neurons.

In insects, steroid hormones named ecdysteroids elicit molting and metamorphosis. The prothoracic gland (PG) is a predominant source of ecdysteroids, where their biosynthesis (ecdysteroidogenesis) is regulated by several neuropeptides. Here, we report that FMRFamide-related peptides (FaRPs) regulate ecdysteroidogenesis through direct innervation of the PG in the silkworm Bombyx mori. We purified a previously uncharacterized Bombyx FaRP, DPSFIRFamide, and identified the corresponding Bombyx FMRFamide gene (Bommo-FMRFamide, BRFa), which encodes three additional FaRPs. All BRFa peptides suppressed ecdysteroidogenesis in the PG by reducing cAMP production by means of the receptor for Bommo-myosuppressin, another FaRP we have previously shown to act as a prothoracicostatic factor. BRFa is predominantly expressed in neurosecretory cells of thoracic ganglia, and the neurons in the prothoracic ganglion innervate the PG to supply all four peptides to the gland surface. Electrophysiological recordings during development confirmed the increased firing activity of BRFa neurons in stages with low PG activity and decreased ecdysteroid levels in the hemolymph. To our knowledge, this study provides the first report of peptides controlling ecdysteroidogenesis by direct innervation.

Amino Acid Sequence↗

PubMed2006

Absolute configurations of brominated sesquiterpenes determined by vibrational circular dichroism.

Two brominated sesquiterpenes, majapolene B (1) and acetylmajapolene B (2), isolated from the red algal genus Laurencia were investigated using vibrational circular dichroism (VCD). The ab initio theoretical VCD and IR calculations of 1 and 2 were performed by density functional theory (DFT) using the B3PW91/6-31G(d,p) basis set. The experimental VCD spectra and corresponding population-weighted theoretical VCD spectra were found to be in excellent agreement in CCl(4) solution in the 1800-850 cm(-1) region, which allowed unambiguous determination of the absolute configurations of (-)-1 and (-)-2 as 7S,10S and 7S,10S, respectively.

Bromine↗

PubMed2006

D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol alters cellular cholesterol homeostasis by modulating the endosome lipid domains.

D-threo-1-phenyl-2-decanoylamino-3-morpholino-1-propanol (D-PDMP) is a frequently used inhibitor of glycosphingolipid biosynthesis. However, some interesting characteristics of D-PDMP cannot be explained by the inhibition of glycolipid synthesis alone. In the present study, we showed that d-PDMP inhibits the activation of lysosomal acid lipase by late endosome/lysosome specific lipid, bis(monoacylglycero)phosphate (also called as lysobisphosphatidic acid), through alteration of membrane structure of the lipid. When added to cultured fibroblasts, D-PDMP inhibits the degradation of low-density lipoprotein (LDL) and thus accumulates both cholesterol ester and free cholesterol in late endosomes/lysosomes. This accumulation results in the inhibition of LDL-derived cholesterol esterification and the decrease of cell surface cholesterol. We showed that D-PDMP alters cellular cholesterol homeostasis in a glycosphingolipid-independent manner using L-PDMP, a stereoisomer of D-PDMP, which does not inhibit glycosphingolipid synthesis, and mutant melanoma cell which is defective in glycolipid synthesis. Altering cholesterol homeostasis by D-PDMP explains the unique characteristics of sensitizing multidrug resistant cells by this drug.

1-Deoxynojirimycin↗

PubMed2006

Structural characterization of glycopeptides by N-terminal protein ladder sequencing.

High-sensitivity and high-throughput mass spectrometry (MS) has become an important tool for characterizing glycopeptides. Here, we analyzed synthetic O-linked glycopeptides using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) MS. First, we applied MALDI-quadrupole ion trap (QIT)-TOF MS, which enables collision-induced dissociation-MSn analysis for fine structural characterization. Subsequent MS/MS of sodium adduct ions selected as precursor ions yielded detailed information about the site of oligosaccharide attachment as well as the carbohydrate and amino acid sequences; however, these MS/MS spectra were very complex. To obtain easily interpretable and simple spectra, we used N-terminal protein ladder sequencing coupled with MALDI-TOF MS. From the extremely simple resulting spectra, we were able to determine the glycosylation sites, amino acid sequences, and oligosaccharide molecular weights of the glycopeptides.

Amino Acid Sequence↗

PubMed2006

Analysis of interfractional set-up errors and intrafractional organ motions during IMRT for head and neck tumors to define an appropriate planning target volume (PTV)- and planning organs at risk volume (PRV)-margins.

BACKGROUND AND PURPOSE: To analyze the interfractional set-up errors and intrafractional organ motions and to define appropriate planning target volume (PTV)- and planning organs at risk volume (PRV)-margins in intensity-modulated radiotherapy (IMRT) for head and neck tumors. PATIENTS AND METHODS: Twenty-two patients with head and neck or brain tumors who were treated with IMRT were enrolled. The set-up errors were defined as the displacements of the coordinates of bony landmarks on the beam films from those on the simulation films. The organ motions were determined as the displacements of the coordinates of the landmarks on the images recorded every 3 min for 15 min on the X-ray simulator from those on the initial image. RESULTS: The standard deviations (SDs) of the systematic set-up errors (Sigma-INTER) and organ motions (Sigma-intra) distributed with a range of 0.7-1.3 and 0.2-0.8 mm, respectively. The average of the SDs of the random set-up errors (sigma-INTER) and organ motions (sigma-intra) ranged from 0.7 to 1.6 mm and from 0.3 to 0.6 mm, respectively. Appropriate PTV-margins and PRV-margins for all the landmarks ranged from 2.0 to 3.6 mm and from 1.8 to 2.4 mm, respectively. CONCLUSIONS: We have adopted a PTV-margin of 5mm and a PRV-margin of 3mm for head and neck IMRT at our department.

Adult↗

PubMed2006

Evaluation of hypoxia-specific cytotoxic bioreductive agent-sodium borocaptate-10B conjugates as 10B-carriers in boron neutron capture therapy.

PURPOSE: To evaluate the usefulness of 5 new 10B-compounds (TX-2091, TX-2095, TX-2097, TX-2100, and TX-2110) as 10B-carriers in boron neutron capture therpy (BNCT). They were conjugates that had been synthesized from a hypoxia-specific cytotoxic bioreductive agent, quinoxaline oxide TX-402, and a clinically used 10B-carrier, sodium borocaptate-10B (BSH). MATERIALS AND METHODS: The 5 new compounds were hybrid compounds that have both a hypoxic cytotoxin unit and a thermal neutron-sensitizing unit, BSH. These new compounds and BSH were administered intraperitoneally to SCC VII tumor-bearing mice. Then, the 10B concentrations in the tumors and normal tissues were measured by gamma-ray spectrometry. Subsequently, SCC VII tumor-bearing mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells in the tumors, then treated with TX-2100, which was chosen based on the results of the above-mentioned biodistribution analyses, or BSH in the same manner as in the biodistribution studies. Right after irradiation, during which intratumor 10B concentrations were kept at levels similar to each other, the tumors were excised, minced, and trypsinized. The tumor cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker), and the micronucleus (MN) frequency in cells without BrdU labeling [= quiescent (Q) cells] was determined using immunofluorescence staining for BrdU. Meanwhile, the MN frequency in the total (P+Q) tumor cell population was determined from the tumors that were not pretreated with BrdU. Clonogenic cell survival was also determined in mice given no BrdU. RESULTS: 10B biodistribution analyses in tumors, brain, skin, muscles, blood, and liver indicated that TX-2100 has the most favorable characteristics for concentrating a sufficient amount of 10B in tumors and maintaining a high enough 10B concentration during irradiation. In addition, TX-2100 had a significantly stronger radio-sensitizing effect with reactor thermal neutron beams than BSH on both total and Q cells in solid tumors. Further, TX-2100 clearly exhibited a radio-sensitizing effect with gamma-rays not only on total cells but also on Q and hypoxic tumor cells, which was not achieved by BSH. CONCLUSION: A 10B-carrier that acts as a hypoxic cytotoxin on tumor cells as well as having the potential to keep 10B in tumors and sensitize tumor cells more markedly than conventional 10B-carriers, such as TX-2100, is a promising candidate for use in BNCT.

Animals↗

PubMed2006

Preservation of pelvic circulation with hypogastric artery bypass in endovascular repair of abdominal aortic aneurysm with bilateral iliac artery aneurysms.

PURPOSE: The endovascular repair (EVAR) of an abdominal aortic aneurysm (AAA) with a bilateral common iliac artery aneurysm (CIAA) often requires exclusion of the bilateral hypogastric artery (HA), which can be associated with pelvic ischemic complications such as erectile dysfunction and buttock claudication. This study assessed the effect of HA bypass on improving pelvic circulation. METHODS: Five patients who underwent endovascular repair with HA bypass for an AAA with bilateral CIAA were evaluated. In all patients, the patency of the inferior mesenteric artery and bilateral HAs arteries was confirmed with preoperative computed tomography (CT) scans and angiography. During EVAR, penile blood flow was monitored with pulse-volume plethysmography measuring the penile brachial pressure index (PBI), and bilateral buttock blood flow was monitored with near-infrared spectroscopy measuring the gluteal tissue oxygenation index (TOI). An aortouni-external iliac artery stent graft with a crossover bypass was performed after embolization of the contralateral HA. HA bypass was performed between the crossover bypass graft and the ipsilateral HA via a retroperitoneal incision. RESULTS: Unilateral coil embolization of the contralateral side HA trunk slightly decreased blood flow to the contralateral side buttock but did not cause significant changes in penile blood flow. At the completion of EVAR, the levels of both PBI and the contralateral side TOI were significantly lower than the baseline levels. After ipsilateral side HA revascularization with HA bypass, both PBI and bilateral gluteal flow returned almost to the baseline levels. Postoperative angiography and CT scans demonstrated the patency of all HA bypasses and no endoleaks. None of the patients experienced new onset of erectile dysfunction or buttock claudication 1 month after surgery. CONCLUSION: Bilateral HA interruption during EVAR for AAA with bilateral CIAA was associated with significant depletion of both penile and gluteal blood flow. Intraoperative monitoring of PBI and TOI at the bilateral buttocks showed significant improvement of both parameters after HA bypass. HA bypass is an excellent procedure to improve pelvic circulation despite its increased surgical complexity.

Aged↗

PubMed2006

The usefulness of mild temperature hyperthermia combined with a newly developed hypoxia-oriented 10B conjugate compound, TX-2100, for boron neutron capture therapy.

PURPOSE: To evaluate the usefulness of a new 10B-compound (TX-2100) as a 10B-carrier in boron neutron capture therapy (BNCT), compared with the simultaneous use of its component drugs, sodium borocapate-10B (BSH) and 3-amino-2-quinoxalinecarbonitrile 1,4-dioxide (TX-402). Further, the usefulness of mild temperature hyperthermia (MTH, 40 degrees Celsius, 30 min) combined with TX-2100 was also examined compared with MTH combined with the concurrent administration with its component drugs. MATERIALS AND METHODS: TX-2100 is a hybrid compound that has both a hypoxic cytotoxin unit (TX-402) and a thermal neutron-sensitizing unit (BSH). TX-2100 or both TX-402 plus BSH in combination with MTH or not was administered to SCC VII tumour-bearing mice intra-peritoneally. Then, the 10B concentrations in the tumours and normal tissues were measured by gamma-ray spectrometry. Meanwhile, SCC VII tumour-bearing mice were continuously given 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells in the tumours, then treated with TX-2100, TX-402 plus BSH or BSH only, in the same manner as in the biodistribution experiments, either with or without MTH. Right after thermal neutron irradiation during which intra-tumour 10B concentrations remained at similar levels, the tumours were excised, minced and trypsinized. The tumour cell suspensions thus obtained were incubated with cytochalasin-B (a cytokinesis blocker) and the micronucleus (MN) frequency in cells without BrdU labelling (=quiescent (Q) cells) was determined using immunofluorescence staining for BrdU. Meanwhile, the MN frequency in the total (P + Q) tumour cell population was determined from the tumours that were not pre-treated with BrdU. The clonogenic cell survival was also determined in mice given no BrdU. RESULTS: 10B biodistribution analyses in tumours, brain, skin, muscles, blood and liver indicated that the administration of TX-2100 plus MTH is most favourable for concentrating a sufficient amount of 10B in tumours and maintaining a high enough 10B concentration during irradiation. In addition, MTH had a stronger sensitizing effect when combined with TX-2100 than with the concurrent administration of its components TX-402 and BSH on both the total and Q cell populations in solid tumours. CONCLUSION: MTH was very effective in combination with the newly-developed TX-2100. The sensitizing effect in combination with MTH should be examined when new 10B-carriers are designed.

Animals↗

PubMed2006

Effects of boron neutron capture therapy on human oral squamous cell carcinoma in a nude mouse model.

PURPOSE: The effect of boronophenylalanine (BPA)-mediated boron neutron capture therapy (BNCT) on human oral squamous cell carcinoma (SCC) xenografts in nude mice was examined. MATERIALS AND METHODS: Tumor-bearing mice were given BPA at a dose of 250 mg/kg body weight. The tumor (10)B concentration 2 h after an injection of BPA was higher than those 1 or 3 h after the injection. Neutron irradiation was performed beginning 1, 2 or 3 h after an injection of BPA and the effects on body weight of the animals, tumor growth, survival of tumor-bearing animals, and histology of tumor and normal tissue were examined. Fragmented nuclear DNA, 5-bromo-2'-deoxyuridine (BrdU), and von Willebrand Factor (vWF) were detected by immunohistochemical staining. RESULTS: Tumor volumes of untreated control animals increased continuously, whereas those of BNCT-treated animals were markedly decreased. Animals given neutron irradiation 2 h after the injection of BPA survived for a longer period as compared with those given neutron irradiation 1 or 3 h after the injection. BNCT reduced the incorporation of BrdU into tumor cells, and induced the enlargement and vacuolation of tumor cells. Disintegration of blood vessels and dense inflammatory cell infiltration were also observed in the stroma of the tumor, but not surrounding normal tissues. CONCLUSION: These results indicate that BPA-mediated BNCT can exert a curative effect on human oral SCC xenografts in nude mice, if an optimal 10B concentration in tumors is achieved and that the disintegration of blood vessels in tumor stroma may contribute to tumor remission by BNCT.

Animals↗

PubMed2006

Convenient structural analysis of glycosphingolipids using MALDI-QIT-TOF mass spectrometry with increased laser power and cooling gas flow.

Matrix-assisted laser desorption/ionization quadrupole ion trap time-of-flight mass spectrometry (MALDI-QIT-TOF MS) was applied to the structural characterization of neutral glycosphingolipids. Lithium adduct ions of glycosphingolipids were analyzed using MALDI-QIT-TOF MS under strong conditions of increased laser power and cooling gas flow. The relative intensities of fragment ions were increased under the strong conditions, and the resulting spectra revealed the presence of oligosaccharide ions fragmented from the glycosphingolipids. Consequently, the oligosaccharide sequences of the glycosphingolipids were readily obtained. To obtain more detailed structural information, MS/MS (MS2) and MS/MS/MS (MS3) analyses were performed with selection of the lactosylceramide and ceramide ions, respectively. The resulting data were sufficient to determine the structures of both the oligosaccharide and the ceramide moiety of each glycosphingolipid. The fragmentation patterns of MS2 and MS3 for Forssman glycolipid under the strong conditions were comparable to those of MS3 and MS4 obtained under standard conditions, respectively. Thus, MALDI-QIT-TOF MS with increased laser power and cooling gas flow is a convenient method for glycosphingolipid analysis.

Carbohydrate Sequence↗

PubMed2006

Intraperitoneal administration of hyperbarically oxygenated perfluorochemical enhances preservation of intestinal mucosa against ischemia/reperfusion injury.

Perfluorochemicals (PFCs) have a high solubility for oxygen. We have previously demonstrated the effect of peritoneal lavage with oxygenated PFC (O2-PFC) on ameliorating ischemia/reperfusion (I/R)-induced intestinal ischemic damage in an animal model. In this study, we applied hyperbarically O2-PFC (HBO-PFC) to investigate whether a larger amount of oxygen carried by PFC could enhance the protective effect of O2-PFC during intestinal malperfusion. Rats were subjected to ischemia by clamping the superior mesenteric artery (SMA) for 90 min. The SMA was then declamped. Rats were divided into four groups. In group A, only anesthesia and abdominal incision were performed. In group B, SMA was clamped without O2-PFC. In group C, during the SMA clamp, 1 atm O2-PFC was injected into the abdominal cavity. In group D, 5 atm O2-PFC (HBO-PFC) was prepared using a custom-made hyperbaric oxygen tank and administered to the abdominal cavity during the SMA clamp. Ileal tissue adenosine triphosphate (ATP) levels 90 min after SMA declamping were determined using luciferase assay. To assess intestinal mucosal barrier function at 90 min after release of the SMA clip, everted gut sacs were prepared to measure the mucosal-to-serosal passage of fluorescein-conjugated dextran (FD4, molecular weight = 4 kDa). Thirty minutes after i.p. administration, partial pressure of oxygen in HBO-PFC remained around 1000 mmHg, whereas partial pressure of oxygen in 1 atm O2-PFC decreased to around 400 mmHg. The intestinal tissue ATP was significantly preserved in group D. Moreover, the mucosal hyperpermeability of the gut sac after I/R was significantly ameliorated in group D. Hyperbarically oxygenated perfluorochemical might supply a larger amount of oxygen to ischemic tissue during SMA clamp, which protected the small intestine from I/R injury, possibly caused by the maintenance of tissue ATP levels during ischemia.

Adenosine Triphosphate↗

PubMed2006

Synergistic effects of radiation and beta-lapachone in DU-145 human prostate cancer cells in vitro.

It has been reported that beta-lapachone (beta-lap), a bioreductive anti-cancer drug, synergistically interacts with ionizing radiation and that the sensitivity of cells to beta-lap is closely related to the activity of NAD(P)H:quinone oxidoreductase 1 (NQO1). Here we report the results of our studies of mechanisms underlying the synergistic interaction of beta-lap and radiation in killing cancer cells using the DU-145 human prostate cancer cell line. The clonogenic cell death caused by the combination of radiation and beta-lap was synergistic when beta-lap was administered 0-10 h after irradiation but not when it was given before irradiation. The expression and activity of NQO1 increased significantly and remained elevated for longer than 12 h after 4 Gy irradiation, suggesting that the long-lasting elevation of NQO1 sensitized the cells to beta-lap. Studies with split-dose irradiation demonstrated that beta-lap given immediately after irradiation effectively inhibited sublethal radiation damage (SLD) repair. Taken together, these results lead us to conclude that the synergistic interaction between beta-lap and radiation in killing cells is the result of two distinct mechanisms: First, radiation sensitizes cells to beta-lap by up-regulating NQO1, and second, beta-lap sensitizes cells to radiation by inhibiting SLD repair. The combination of beta-lap and radiotherapy is potentially promising modality for the treatment of cancer in humans.

Cell Line, Tumor↗