Acute-phase response alters the disposition kinetics of cefepime following intravenous administration to rabbits

The effect of experimentally induced fever on the pharmacokinetics of cefepime administered intravenously at a dose of 75 mg/kg bw was studied in six healthy rabbits. The study was conducted in two consecutive phases, separated by a washout period of 2 weeks. Infection was induced by the intravenous inoculation of 5 x 10(8) cfu of Escherichia coli 24 h before the pharmacokinetic investigation was carried out. Serial blood samples for cefepime concentration determination were obtained for 48 h following drug administration. The concentrations of cefepime in the plasma were determined by a quantitative microbiological assay using an agar-gel diffusion method employing Bacillus subtilis ATCC 6633 as the test organism, with a level of detectability of approximately 0.10 microg/ml. Cefepime plasma concentrations versus time were evaluated by non-compartmental methods using WinNonLin. Cefepime was well tolerated and no serious adverse events were observed. Rectal temperature increased 1 degree C 24 h post injection in infected animals. Highly significant differences in the blood plasma concentrations of cefepime were observed between febrile and healthy animals at all the sampling times. This could explain the greater area under the plasma level-time curve of the drug in febrile compared with healthy animals. The results from pharmacokinetic calculations showed that both the distribution volume at steady state (V (dss)) and body clearance (CL(tot)) were affected in febrile as compared to healthy animals. The mean values of V (dss) and CL(tot) of cefepime in healthy rabbits were 1.168 L/kg and 0.303 L/kg/h, respectively. As compared with healthy animals, the mean estimates of V (dss) (0.917 L/kg) and CL(tot) (0.205 L/kg per h) of cefepime were significantly lower, whereas t (1/2lambda), MRT and AUMC were significantly higher in febrile rabbits. It is concluded that, although experimental infection had an effect on the disposition kinetics of cefepime in healthy and febrile rabbits, this was not sufficiently pronounced to require alteration of the dosage during disease.

Low loss high mesa optical waveguides based on InGaAsP/InP heterostructures

Low loss high mesa optical waveguides were fabricated on InGaAsP/InP heterostructures by utilizing inductively-coupled-plasma reactive ion etching (ICP-RIE) and electron beam lithography technique. The fabrication process was optimized by measuring sidewall roughness of deep-etched waveguides. Atomic force microscope loaded with carbon nanotude was used to obtain three-dimensional image of the etched sidewall of waveguides. The obtained statistical information such as rms roughness and correlation length was used to theoretically calculate scattering loss of waveguides. Several waveguides with different number of sharp bends and the length were fabricated and their propagation losses were measured by modified Fabry-Perot method. The measured propagation losses were compared with theoretically calculated losses.

Surface adsorption of DNA to tissue engineering scaffolds for efficient gene delivery

Gene delivery from tissue engineering scaffolds has potential to promote localized transgene expression that can induce the formation of functional tissues. Substrate-mediated delivery, an alternative delivery strategy to sustained release, is based on immobilization of DNA complexes to the polymer surface for subsequent delivery to cells cultured on the substrate. We investigate polyethylenimine (PEI)/DNA complex immobilization and subsequent cellular transfection on tissue engineering scaffolds fabricated from poly(lactide-co-glycolide) (PLG). The properties of the substrate and the complex affect both immobilization and cellular transfection. PLG promotes binding of PEI/DNA complexes, with percent bound independent of the N/P ratio or the DNA dosage. The levels of transgene expression are similar to or greater than control studies based on bolus DNA delivery, with orders of magnitude less DNA. Immobilization also homogeneously distributes the DNA throughout the scaffold, resulting in large numbers of transfected cells (>60%) at low surface quantities (<50 ng). Importantly, this approach can be employed to transfect cells throughout a three-dimensional scaffold. Tissue engineering scaffolds that are prefabricated into various shapes from a range of materials could potentially employ this strategy for numerous applications.

Intramuscular delivery of DNA releasing microspheres: microsphere properties and transgene expression

Plasmid-loaded microspheres can provide localized and sustained release into the target tissue, and thus have the potential to enhance the efficiency of naked DNA at promoting transgene expression. In this report, microsphere design parameters are investigated by correlating the extent and duration of transgene expression intramuscularly to the polymer molecular weight and the mass of DNA delivered. Plasmid DNA was incorporated into poly (lactide-co-glycolide) microspheres using a cryogenic double emulsion process, and microspheres were injected intramuscularly. Bolus injection of naked plasmid was used for control, which exhibited transfection of muscle cells with transgene expression that gradually decreased over time. Microspheres fabricated from low molecular weight polymer had expression levels that increased from day 1 to day 92, which subsequently decreased through day 174. Decreasing the microsphere mass delivered resulted in steady expression during the same time. However, microspheres fabricated with high molecular weight polymer had expression for only 14 days. Intramuscular injection resulted in a foreign body response to the microspheres, and these infiltrating cells adjacent were primarily transfected. This understanding of microsphere properties that determine transgene expression and the distribution of transfected cells may facilitate their application to fields such as tissue engineering or DNA vaccines.

Concurrent chemoradiotherapy in patients with nasopharyngeal cancer: prognostic significance of low expression of bax

A randomized trial has demonstrated that concurrent chemoradiotherapy (CRT) is superior to radiotherapy (RT) alone in locally advanced nasopharyngeal cancer (NPC). Our study comprise 35 patients with locally advanced NPC (stage I: 1, II: 12, III: 7, IV: 15) with 1 cycle of induction chemotherapy (5-fluorouracil 1,000 mg/m(2)/day and cisplatin 20 mg/m(2)/day, days 1- 4) followed by concurrent CRT starting on day 22. Concurrent CRT consisted of RT (70 Gy/35 fractions for 7 weeks) with cisplatin 20 mg/m(2)/day for 4 days on weeks 1, 4, 7 of RT. Complete response (CR) was achieved in 33 patients (94%). Four-year progression-free survival (PFS) and overall survival (OS) of all patients were 57% and 65%, respectively. In analysis of prognostic factors, low expression of bax was the most significant independent predictor of poor prognosis in both PFS (p=0.002) and OS (p=0.008). In conclusion, the outcome of patients treated with this combined therapeutical modality appears to be comparable with that of Intergroup 0099 trial with high CR rate. Low expression of bax was significantly associated with poor PFS and OS.

Plasmid delivery in vivo from porous tissue-engineering scaffolds: transgene expression and cellular transfection

Tissue engineering scaffolds capable of sustained plasmid release can promote gene transfer locally and stimulate new tissue formation. We have investigated the scaffold design parameters that influence the extent and duration of transgene expression and have characterized the distribution of transfected cells. Porous scaffolds with encapsulated plasmid were fabricated from poly(lactide-co-glycolide) with a gas foaming procedure, with wet granulation employed to mix the components homogeneously prior to foaming. Wet granulation enhanced plasmid incorporation relative to standard procedures and also enhanced in vivo transgene expression, possibly through the increased loading and maintenance of the scaffold pore structure. The plasmid loading regulated the quantity and duration of transgene expression, with expression for 105 days achieved at the highest dosage. Expression was localized to the implantation site, though the distribution of transfected cells varied with time. Transfected cells were initially observed at the scaffold periphery (day 3), then within the pores and adjacent to the polymer (day 17), and finally throughout the scaffold interior (day 126). Delivery of a plasmid encoding VEGF increased the blood vessel density relative to control. Correlating scaffold design with gene transfer efficiency and tissue formation will facilitate application of plasmid-releasing scaffolds to multiple tissues.

Effects of high concentrations of energy sources and metabolites on suspension culture of Chinese hamster ovary cells producing tissue plasminogen activator

A high-concentration medium was developed for the high-density cultivation of Chinese hamster ovary (CHO) cells to produce tissue plasminogen activator (tPA). First, the effects of the concentrations of several medium components on the growth and metabolism of CHO cells were studied particularly in relation to the serum concentration, in order to develop a suitable concentrated medium. High concentrations of serum, glucose, lactate, and glutamine and a low ammonia concentration increased the specific growth rate and decreased the specific tPA production rate. Among these components, the effect of the serum concentration was the most significant. There was an inverse correlation between the specific rates of cell growth and tPA production. Using a medium containing glutamine at twice the concentration of the original medium (F-12) allowed the medium volume to be reduced to seven-ninths that of the original, without any reduction in tPA productivity. When the F-12 medium was supplemented five-fold with amino acids and vitamins, the total amount of tPA produced, specific rate of tPA production, and yield of tPA per unit volume of medium employed were respectively enhanced 1.7, 1.5, and 3.6 times. As a consequence, the frequency of medium exchange could be reduced. The results strongly indicate that the supplementation of nutrient amino acids and vitamins to a medium with a low concentration of serum are the most critical factors for cost-effective tPA production in high-density cell cultivation.

Neurotrophin releasing single and multiple lumen nerve conduits

Tissue engineering strategies for nerve repair employ polymer conduits termed guidance channels and bridges to promote regeneration for peripheral nerve injury and spinal cord injury, respectively. An approach for fabrication of nerve conduits with single and multiple lumens capable of controlled release of neurotrophic factors was developed. These conduits were fabricated from a mixture of poly(lactide-co-glycolide) (PLG) microspheres and porogen (NaCl) that was loaded into a mold and processed by gas foaming. The porosity and mechanical properties of the constructs were regulated by the ratio of porogen to polymer microsphere. The neurotrophin, nerve growth factor (NGF), was incorporated into the conduit by either mixing the protein with microspheres or encapsulating the protein within microspheres prior to gas foaming. A sustained release was observed for at least 42 days, with the release rate controlled by method of incorporation and polymer molecular weight. Released NGF retained its bioactivity, as demonstrated by its ability to stimulate neurite outgrowth from primary dorsal root ganglion (DRG). In vivo results indicate that conduits retain their original architecture, and allow for cellular infiltration into the channels. Polymer conduits with controllable lumen diameters and protein release may enhance nerve regeneration by guiding and stimulating neurite outgrowth.

Enhancement of styrene removal by Pseudomonas sp. SR-5 in mixed culture with a benzoic acid-degrading bacterium in biofilter

The growth of a styrene-degrading bacterium, Pseudomonas sp. SR-5, was inhibited by benzoic acid (BA), one of the styrene degradation intermediates, in liquid culture. A benzoic acid-degrading microorganism, Raoultella sp. strain A, was isolated from a peat biofilter inoculated with a wastewater. The styrene removal efficiencies of the two laboratory-scale biofilters inoculated with only strain SR-5 and a mixed culture of strains SR-5 and A were compared using a mixed packing material of peat and ceramic (1:1) for 45 days. The biofilter with the mixed culture showed a higher removal efficiency than that with a single culture of SR-5. The maximum elimination capacities of the biofilters with the mixed culture and the single culture were 141 g m(-3)h(-1) and 106 g m(-3)h(-1), respectively. In the biofilter with the single culture, 136 g of benzoic acid (m3 of dry packing material)(-1) was accumulated at the end of the experiment. However, no accumulation of benzoic acid was observed in the biofilter with the mixed culture.

Gene delivery through cell culture substrate adsorbed DNA complexes

Efficient gene delivery is a fundamental goal of biotechnology and has numerous applications in both basic and applied science. Substrate-mediated delivery and reverse transfection enhance gene transfer by increasing the concentration of DNA in the cellular microenvironment through immobilizing a plasmid to a cell culture substrate prior to cell seeding. In this report, we examine gene delivery of plasmids that were complexed with cationic polymers (polyplexes) or lipids (lipoplexes) and subsequently immobilized to cell culture or biomaterial substrates by adsorption. Polyplexes and lipoplexes were adsorbed to either tissue culture polystyrene or serum-adsorbed tissue culture polystyrene. The quantity of DNA immobilized increased with time of exposure, and the deposition rate and final amount deposited depended upon the properties of the substrate and complex. For polyplexes, serum modification enhanced reporter gene expression up to 1500-fold relative to unmodified substrates and yielded equivalent or greater expression compared to bolus delivery. For lipoplexes, serum modification significantly increased the number of transfected cells relative to unmodified substrates yet provided similar levels of expression. Immobilized complexes transfect primary cells with improved cellular viability relative to bolus delivery. Finally, this substrate-mediated delivery approach was extended to a widely used biomaterial, poly(lactide-co-glycolide). Immobilization of DNA complexes to tissue culture polystyrene substrates can be a useful tool for enhancing gene delivery for in vitro studies. Additionally, adapting this system to biomaterials may facilitate application to fields such as tissue engineering.

Peripheral glutamate receptors contribute to mechanical hyperalgesia in a neuropathic pain model of the rat

We hypothesized that glutamate (Glu) released from the peripheral terminals of primary afferents contributes to the generation of mechanical hyperalgesia following peripheral nerve injury. Nerve injury was performed on rats with a lumbar 5 spinal nerve lesion (L5 SNL), which was preceded by L5 dorsal rhizotomy (L5 DR) to avoid the potential central effects induced by L5 SNL through the L5 dorsal root. Mechanical hyperalgesia, as evidenced by a reduction in paw withdrawal threshold (PWT), was short-lasting (<6 days) after L5 DR, but persistent (>42 days) after L5 SNL preceded by L5 DR. When an intraplantar injection into the affected hind paw was given immediately before L5 SNL, non-competitive N-methyl-D-aspartate (NMDA) receptor antagonist MK-801 (20 nmol), group-I metabotropic Glu (mGlu) receptor antagonist DL-amino-3-phosphonopropionic acid (DL-AP3; 70 nmol), and selective group-II mGlu receptor agonist 4-aminopyrrolidine-2,4-dicarboxylate (APDC; 20 nmol) delayed the onset of PWT reduction for 1-4 days. However, this onset was not affected by alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid/kainate receptor antagonist 2,3-dioxo-6-nitro-1,2,3,4,-tetrahydrobenzo[f]quinoxaline-7-sulfonamide (NBQX; 100 nmol). When the same injection was given after L5 SNL-induced mechanical hyperalgesia had been established, MK-801 reversed the PWT reduction for 30-75 min, whereas NBQX, DL-AP3, or APDC had no effect. These results suggest that the manipulation of the peripheral Glu receptors reduces neuropathic pain, by blocking NMDA and group-I mGlu receptors and by stimulating group-II mGlu receptor during the induction phase of neuropathic pain, but only by blocking the NMDA receptor during its maintenance phase.

Ion channels of Fasciola hepatica incorporated into planar lipid bilayers

Ion channels are important target sites of anthelmintics, but little is known about those in Fasciola hepatica. In this work, we applied a planar lipid bilayer technique to characterize the properties of single ion channels in F. hepatica. Under a 200/40 mM KCl gradient, a large conductance channel of 251 pS was observed in 18% of the membranes studied. The channel was selective to K(+) over Cl(-) with a permeability ratio of K(+) to Cl(-) (PK/PCl) of 4.9. Open state probability (Po) of the channel was less than 0.5 and dependent on voltage (-60 to approximately +40 mV) and Ca(2+) (approximately 100 microM). The other two types of single channels observed in 11 and 5% of membranes, respectively, were a K(+)-permeable channel of 80 pS (PK/PCl=4.6) and a Cl(-)-permeable channel of 64 pS (PK/PCl=0.058). Open state probability of both channels showed little voltage dependence. The results indicate that distinct single channels of 60 to approximately 251 pS are present in relative abundance and, in addition, that the planar lipid bilayer technique can be a useful tool for the study of single ion channels in F. hepatica.

Styrene degradation by Pseudomonas sp. SR-5 in biofilters with organic and inorganic packing materials

Pseudomonas sp. SR-5 was isolated as a styrene-degrading bacterium. In liquid culture containing 1% (v/v) styrene, more than 90% styrene was degraded in 53 h and the doubling time of SR-5 was 2 h. The removal of styrene gas was investigated in biofilters for 31 days using an organic packing material of peat and an inorganic packing material of ceramic inoculated with SR-5. The maximum-styrene-elimination capacities for peat and ceramic packing materials were 236 and 81 g m(-3) h(-1), respectively. The percentage of styrene converted to low molecular weight compounds including CO(2) in the peat and ceramic biofilters during a 10-day operation were estimated to be 90.4 and 36.7%, respectively. As the pressure drop in the peat bioflter at the end of experiment was significantly higher than that in ceramic biofilter, a biofilter using a mixture of peat and ceramic was tested. We determined that the maximum elimination capacity was 170 g m(-3) h(-1) and the production of low molecular weight compounds was 95% at a low pressure drop for this mixed packing material filter.

Controllable delivery of non-viral DNA from porous scaffolds

The inductive approach to tissue engineering combines three-dimensional porous scaffolds with drug delivery to direct the action of progenitor cells into a functional tissue. We present an approach to fabricate scaffolds capable of controlled, sustained delivery by the assembly and subsequent fusion of drug-loaded microspheres using a gas foaming/particulate leaching process. DNA-loaded microspheres were fabricated from the copolymers of lactide and glycolide (PLG) using a cryogenic double emulsion process. Microspheres were fabricated in four populations with mean diameters ranging from 12.3 microm to 92.5 microm. Scaffolds fabricated by fusion of these microspheres had an interconnected open pore structure, maintained DNA integrity, and exhibited sustained release for 21 days. Control over the release was obtained through manipulating the properties of the polymer, microspheres, and the foaming process. Decreasing the microsphere diameter or the molecular weight of the polymer used for microsphere fabrication led to increased rates of release from the porous scaffold. Additionally, increasing the pressure of CO(2) increased the DNA release rate. The ability to create porous polymer scaffolds capable of controlled release rates may provide a means to enhance and regulate gene transfer within a developing tissue, which will increase their utility in tissue engineering.

Motility restriction after resection of an extraocular muscle

Restriction of eye movement after surgery is an unusual but troublesome complication. A patient presented with a limitation of abduction after a 5 mm resection of medial rectus muscle and an 8 mm recession of lateral rectus muscle. Since the forced duction test was positive, restrictive factors were suggested to be implicated. A reparative operation was performed at the postoperative 9 month, and the forced duction test was negative after releasing the resected medial rectus muscle. The patient showed an improved abduction after recessing the resected muscle. Even after an uneventful surgery, resection of an extraocular muscle may cause restriction of ocular rotation caused by muscle scarring to the sclera or by an increased tightness of the muscle.

Idarubicin, cytarabine, and topotecan in patients with refractory or relapsed acute myelogenous leukemia and high-risk myelodysplastic syndrome

In an effort to develop more effective therapy for patients with refractory or relapsed acute myelogenous leukemia (AML) and high-risk myelodysplastic syndrome (MDS), we investigated the efficacy of a combination chemotherapy consisting of idarubicin, cytarabine, and topotecan. Twenty-seven patients were treated: four with primary refractory AML, nine with AML in first relapse, four with AML in second relapse, and 10 with MDS-RAEB/RAEBT. Patients received as salvage therapy a single course of idarubicin 12 mg/m(2) IV bolus on days 1-3, cytarabine 1 g/m(2) over two hours q 12 hr on days 1-5, and topotecan 1.25 mg/m(2) over 24 hr on days 1-5. Median age was 42 years (range 17-65 years). All patients were evaluable for response: 14 (51.9%) achieved complete remission, 10 with AML (59%) and four with MDS (40%), respectively. Thirteen AML patients (excluding four relapsed after autologous stem cell transplantation) were grouped into four categories to stratify the probability of achieving complete remission (CR): group 1, first CR duration > or = 2 years and receiving first salvage treatment (S1); group 2, first CR duration 1-2 years and receiving S1; group 3, first CR duration 0-1 years and receiving S1; and group 4, first CR duration 0-1 years and receiving S2, S3, or S4 after failing S1. The response rate of each group was as follows: group 1, one of two (50%); group 2, one of one (100%); group 3, four of four (100%); group 4, two of six (33.3%). The median remission duration and survival of patients with AML were six and 12 months, respectively. Median duration of survival in 10 MDS patients was 15 months, and all four MDS patients achieving a CR maintained continuous CR with a median follow-up of 11 months. Severe myelosuppression was observed in all patients, resulting in fever or documented infections in 89% of patients. Median time to recovery of neutrophils > or =0.5 x 10(9)/l was 22 days (11-34) and for platelets > 20 x 10(9)/l 35 days (11-58). Reversible grade 3-4 toxicities included diarrhea (two patients) and mucositis (seven patients). We conclude that combination chemotherapy with intermediate dose cytarabine, idarubicin, and topotecan has significant antileukemic activity and acceptable toxicity in salvage AML and high-risk MDS.

Protective effects of resveratrol on hydrogen peroxide-induced apoptosis in rat pheochromocytoma (PC12) cells

Oxidative stress has been considered as a major cause of cellular injuries in a variety of clinical abnormalities. One of the plausible ways to prevent the reactive oxygen species (ROS)-mediated cellular injury is dietary or pharmaceutical augmentation of endogenous antioxidant defense capacity. Resveratrol (3,5,4'-trihydroxy-trans-stilbene), one of the major antioxidative constituents found in the skin of grapes, has been considered to be responsible in part for the protective effects of red wine consumption against coronary heart disease ('French Pardox'). In this study, we have investigated the effects of resveratrol on hydrogen peroxide-induced oxidative stress and apoptotic death in cultured rat pheochromocytoma (PC12) cells. PC12 cells treated with hydrogen peroxide underwent apoptotic death as determined by characteristic morphological features, internucleosomal DNA fragmentation and positive in situ end-labeling by terminal transferase (TUNEL staining). Resveratrol pretreatment attenuated hydrogen peroxide-induced cytotoxicity, DNA fragmentation, and intracellular accumulation of ROS. Hydrogen peroxide transiently induced activation of NF-kappaB in PC12 cells, which was mitigated by resveratrol pretreatment. These results suggest that resveratrol has the potential to prevent oxidative stress-induced cell death.

AC133 antigen as a prognostic factor in acute leukemia

AC133 is a novel 5-transmembrane antigen present on a CD34((bright)) subset of human hematopoietic stem cells (HSCs) and it is also expressed on the subset of CD34 positive (CD34(+)) leukemias. But the clinical significance of AC133 expression on leukemic blasts is not yet known. We investigated the expression of AC133 antigen on blast cells of acute leukemia. Forty-one cases of acute leukemia were examined for expression of AC133, CD34, and other antigens using multicolor flow-cytometry. Samples were considered positive if at least 20% of the cells specifically stained with monoclonal antibodies (MoAbs) revealed a higher fluorescence intensity compared to cells of corresponding negative control samples (=20% cut-off level). 14/36 (38.9%) acute myelogenous leukemia (AML) samples and 6/20 (30%) acute lymphoblastic leukemia (ALL) samples were positive for AC133, the difference was not significant. All AC133 positive (AC133(+)) leukemias expressed CD34, whereas 13 of 33 CD34(+) leukemias were negative for AC133, and AC133(+)/CD34(-) leukemia was not found. Expression rates of CD31, CD62L, CD62E, CD105 and CD144 were significantly higher in AC133(+) leukemia compared to those of AC133(-) leukemia (P=0.045, P<0.001, P<0.001, P<0.001, P=0.003, respectively), but bcl-2, CXCR-1, CXCR4, VLA-4, CD106 expression rates were not significantly different between AC133(+) and AC133(-) leukemias. None of the clinical prognostic markers such as age, hemogram, lactate dehydrogenase, and chromosomal aberration were significantly different between AC133(+) and AC133(-) leukemias. CR rates of AC133(+) AML and AC133(-) AML were not significantly different, although there was a trend toward higher CR rates in AC133(-) AML (18/22[81.8%] AC133(-) AML versus 9/14[64.3%] AC133(+) AML), but the 1-year relapse rate of AC133(+) AML was significantly higher than that of AC133(-) AML (8/9 (88.9%) versus 7/19 (36.8%), P=0.016). Median disease-free survival (DFS) times of AC133(+) and AC133(-) AML were significantly different (11 and 18 months, respectively, P=0.006), although overall survival (OS) times were not significantly different (AC133(+) 15 months versus AC133(-) 20 months, respectively, P=0.06). Similar results regarding clinical outcomes were found when AC133(+)/CD34(+) and AC133(-)/CD34(+) were analyzed separately, but the difference did not attain statistical significance. In ALL, 9/11 (81.8%) AC133(-) and 2/4 (50%) AC133(+) cases achieved CR, but the difference was not significant. Four of 11 AC133(-) ALL (36.4%) and 2 of 3 AC133(+) ALL (66.7%) relapsed within 1 year. In survival analysis, median DFS time and OS time of the AC133(+) group were 7 and 18 months, respectively, and these were not significantly different from those of the AC133(-) group (median DFS 15, OS 22 months, respectively). Our results demonstrate that AC133 expression in AML blasts is associated with poor clinical outcomes in terms of higher early relapse and shorter disease-free survival, suggesting that the AC133 antigen might provide the prognostic stratification of acute leukemia. However, to verify the effect of AC133 expression on the therapeutic outcomes of adult acute leukemia, further study including more cases is needed.

Differential cell death induced by salsolinol with and without copper: possible role of reactive oxygen species

Salsolinol (SAL), a novel dopaminergic catechol tetrahydroisoquinoline neurotoxin, has been speculated to contribute to the etiology of Parkinson's disease and neuropathology of chronic alcoholism. Our previous studies have demonstrated that SAL induces strand scission in øX174 supercoiled DNA and oxidative base modification in calf thymus DNA in the presence of cupric ion. We now report that treatment of rat pheochromocytoma (PC12) cells with SAL causes reduced viability, which was exacerbated by Cu(2+). The copper chelator bathocuproinedisulfonic acid ameliorated cytotoxicity induced by SAL and Cu(2+). N-Acetyl-L-cysteine and reduced glutathione protected against SAL- plus Cu(2+)-mediated PC12 cell death. Cells exposed to SAL underwent apoptosis, as revealed by characteristic morphological and biochemical changes. SAL treatment resulted in increased levels of Bax with a concomitant decrease in expression of Bcl-x(L). Furthermore, SAL rapidly activated c-Jun N-terminal kinase, whereas the activity of extracellular signal-regulated protein kinase remained unchanged. Transfection with Bcl-x(L) or Bcl-2 led to protection against SAL-mediated PC12 cell death. Although SAL alone could cause apoptotic death in PC12 cells, cells treated with SAL together with Cu(2+) became necrotic. Cells exposed to both SAL and Cu(2+) exhibited higher levels of intracellular reactive oxygen species, malondialdehyde, and 8-oxo-7,8-dihydro-2'-deoxyguanosine than did those treated with SAL alone. These results suggest that copper accelerates redox cycling of SAL, leading to massive production of reactive oxygen species, which can divert the SAL-induced cell death to necrosis.

Evidence that the intracellular domain of FGF receptor 2IIIb affects contact of the ectodomain with two FGF7 ligands

Models of the oligomeric FGF signaling complex, including those derived from crystal structures, vary in stoichiometry and arrangement of the three subunits comprised of heparin/heparan sulfate chains, FGFR tyrosine kinase and activating FGF. Here, using covalent affinity crosslinking of radiolabeled FGF7 to binary complexes of FGFR2IIIb and heparin, we show that two molecules of FGF7 contact each FGFR2IIIb. This supports models that propose a dimeric complex of two units with stoichiometry 1 FGF:1 FGFR in which each FGF contacts both FGFR. The bivalent FGF7 contact was dependent on the full-length amino terminus of FGF7alpha and the intracellular domain of FGFR2IIIb extending through the juxtamembrane domain and the beta1 and beta2 strands of the kinase which is required for ATP binding. We propose that the differences in crosslinking report differences in relationships among subunits in the ectodomain of the complex that are affected by the amino terminus of FGF and the FGFR intracellular domain. From this, we suggest the corollary that conformational relationships among subunits in the ectodomain are transmitted to the intracellular and ATP binding domains during activation of the complex.

Mutations in fibroblast growth factor receptor 2 and fibroblast growth factor receptor 3 genes associated with human gastric and colorectal cancers

Autosomal dominant disorders of skeletal and cranial development have been linked to fibroblast growth factor receptor (FGFR) 2 and FGFR3. Here we report two identical mutations in FGFR2 that cause craniosynostosis syndromes, Crouzon, Apert, and Pfeiffer in gastric carcinoma. A missense mutation (Ser267Pro) in exon IIIa and a splice site mutation (940-2A-->G) in exon IIIc were detected in gastric cancer patients. Interestingly, these heterozygous somatic mutations are identical to the germinal activating mutations in FGFR2 reported previously in craniosynostosis syndromes. In addition, the two novel mutations of FGFR3 in colorectal carcinomas were identified. All identified mutations occurred at highly conserved sequences, not only in the FGFR family of molecules, but also throughout evolution and clustered in the immunoglobulin-like loop-III domain, highlighting the functional importance of this domain. Our results indicate that FGFR2 and FGFR3, in addition to their potential role in skeletal dysplasias, play an important role in tumorigenesis.

Transplantation of peripheral blood stem cells mobilized by intensified consolidation and granulocyte colony-stimulating factor in acute leukemia

The purpose of this study was to evaluate the feasibility and efficacy of autologous transplantation of peripheral blood stem cells (PBSC) mobilized with high-dose consolidation chemotherapy and granulocyte colony-stimulating factor in patients with acute myelogenous leukemia (AML). Twenty patients received myeloablative chemotherapy or chemo-radiotherapy including total body irradiation followed by the infusion of PBSC. PBSC were collected by large-volume leukaphereses. The mean number of mononuclear cells and CD34-positive cells infused were 7.2 x 10(8)/kg (range, 2.2-16.6), and 6.6 x 106/kg (range, 2.1-27.7), respectively. Engraftment failure was not seen in the enrolled patients. The median time to neutrophil (> or = 500/microL) and platelet recovery (> or = 50,000/microL) from the transplant was 12 days (range, 8-20) and 28 days (range, 10-600), respectively. The 2-year probability of disease-free survival (DFS) and relapse were 43% and 57% for patients with AML transplanted in first complete remission (CR1). The outcome of the patients transplanted in the advanced status was significantly worse than the patients transplanted in CR1 (P=0.04). Most relapses occurred within 1 year after transplantation. Fatal hepatic veno-occlusive disease was observed in one case. Other transplantation-related toxicities were mild. Our results demonstrated that autologous transplantation of high-dose consolidation chemotherapy-mobilized peripheral blood progenitor cells is feasible in the patients with AML in CR1. To further reduce the risk of leukemia relapse, much effort should be contributed to the field of ex vivo purging and post-transplant immunotherapy.

Bioflocculation production from lower-molecular fatty acids as a novel strategy for utilization of sludge digestion liquor

We propose the bioproduction of a bioflocculant from lower-molecular fatty acids as an innovative strategy for utilizing waste sludge digestion liquor. Fundamental studies on the production, characterization and application of a novel bioflocculant were performed. Citrobactersp. TKF04 was screened out of 1,564 natural isolates as a bacterial strain capable of a bioflocculant from acetic and propionic acids. TKF04 produced the bioflocculant during the logarithmic growth in the batch cultivation, and it could be recovered from the culture supernatant by ethanol precipitation. The fed-batch cultivation with feeding of acetic acid: ammonium 10;1 (mole) to maintain pH 8.5 led to the hyper-production of the bioflocculant. The bioflocculant was found to be effective for flocculating a kaolin suspension, when added at a final concentration of 1-10 mg/l, over a wide range of pHs (2-8) and temperatures (3-95 degrees C), while the addition of cations was not required. It could flocculate a variety of inorganic and organic suspended particles including kaolin, diatomite, bentonite, activated carbon, soil and activated sludge. These indicated that the bioflocculant possesses flocculating activity comparable or superior to that of synthetic flocculants. The bioflocculation was identified as a chitosan-like biopolymer.