Kinetic characteristics of bacterial azo-dye decolorization by Pseudomonas luteola

A Pseudomonas luteola strain expressing azoreductase activity was utilized to remove the color of an azo dye (reactive red 22) from contaminated solutions. The effects of substrate concentrations, medium compositions, and operation parameters (e.g., pH, temperature, dissolved oxygen, etc.) on decolorization of the azo dye by a P. luteola strain were systematically investigated to reveal the key factors that dominate the performance of azo-dye decolorization. The metabolites resulting from bacterial decolorization were analyzed by high-performance liquid chromatography (HPLC) and mass spectrometery (MS). The results show that the dissolved oxygen and glucose concentration retarded decolorization of reactive red 22 by P. luteola. The optimal azo-dye decolorization occurred at 37 degrees C, while more rapid decolorization took place over pH 7-9. Yeast extract and tryptone strongly enhanced the decolorization. The Michaelis-Menten model can satisfactorily describe the dependence of specific decolorization rate on the concentration of substrate (reactive red 22 or yeast extract). Decolorization of the azo dye by intact cells of P. luteola was essentially independent of the growth phase, whereas the azoreductase activity of the cell-free extract decreased in the order of late-stationary phase > early-stationary phase > mid-log phase. This suggests that mass transfer of the azo dye across the cell membrane may be the rate-limiting step. The HPLC and MS analyses suggest that both partial reduction and complete cleavage of the azo bond could contribute to decolorization of reactive red 22 by P. luteola.

Evaluation of percutaneous absorption and skin irritation of ketoprofen through rat skin: in vitro and in vivo study

The influences of different mechanisms of penetration enhancers (such as menthol, azone, ethanol and nonivarnide) regarding the percutaneous absorption and skin irritation of ketoprofen formulations through rat skin were investigated by in vitro and in vivo study. The skin irritation degree at the end of the experiment (10 h) was deterinined by pathologic biopsy and colorimetry methods. In vitro, the menthol showed the most potent enhancing effect. Furthermore, the enhancement effect of a combination of menthol and nonivamide was higher than that of their individual use alone. In vivo the formulation containing 0.05% nonivantide, 5% menthol and 20% ethanol showed a higher penetration rate and an acceptable degree of skin irritation compared to a commercial product (Formax plus gel containing 3% ketoprofen), indicating that it could be used in the clinical situation.

Altered expression of phospholipase D1 in spontaneously hypertensive rats

To clarify the involvement of phospholipase D (PLD) in the mechanism underlying genetically-induced hypertension, we investigated the activity and expression levels of PLD in tissues taken from spontaneously hypertensive rats (SHR), and their normotensive controls, Wistar-Kyoto rats (WKY). The ADP-ribosylation factor 3 (ARF3)-dependent PLD activity and protein levels of PLD1 from SHR increased significantly in the brain and liver, but not in the heart and kidney, compared to those of WKY. The activity and expression of PLD were the same between the homogenated whole kidneys of the two strains; however, there were topographical differences in the expression and activity of PLD between the kidneys of the two strains. The activity and expression level of PLD gradually increased from the cortex to the inner medulla of WKY. The enzyme activity, and amount of PLD in the inner stripe of the outer medulla and in the inner medulla, was significantly lower in SHR than in WKY. Taken together, these results suggest that the distinctly distributed patterns of PLD in the kidney may be associated with differential signal transduction pathways that are involved in hypertension in conjunction with an increase of PLD activity in the brain and liver.

Comparative studies on the GABA-transaminase immunoreactivity in rat and gerbil brains

Gamma-aminobutyric acid (GABA) is the most important inhibitory neurotransmitter in the central nervous system (CNS). Degradation of GABA in the CNS is catalyzed by the action of GABA transaminase (GABA-T). However, the neuroanatomical characteristics of GABA-T in the gerbil, which is a useful experimental animal in neuroscience, are still unknown. Therefore, we performed a comparative analysis of the distribution of GABA-T in rat and gerbil brains using immunohistochemistry. GABA-T immunoreactive neurons were observed in the regions which contained GABAergic neurons of both animals: corpus striatum; substantia nigra, pars reticulata; septal nucleus; and accumbens nucleus. GABA-T + neurons were restricted to layers III and V in the rat. Unlike the rat GABA-T + neurons were observed in layers II, III, and V of the gerbil cerebral cortex. These results suggest that the expression of GABA-T in the gerbil brain may be similar to that in the rat brain, except in the cerebral cortex.

Development of Th1-mediated CD8+ effector T cells by vaccination with epitope peptides encapsulated in pH-sensitive liposomes

There have been many studies for tumor therapy mediated by cytotoxic T lymphocytes (CTL) that recognize tumor-associated antigen. It is generally accepted that CTL responses are induced when antigen is delivered into the cytosol. The pH-sensitive liposomes as vehicles are well known for their capacity to deliver the antigen into the cytosol. In this work, immunization of mice with CTL epitope peptides from Hantaan nucleocapsid protein (M6) or human papilloma virus E7 encapsulated in pH-sensitive liposomes induced effective antigen-specific CTL responses. The CTL responses induced by M6 peptide encapsulated in pH-sensitive liposomes blocked the formation of tumor mass from Hantaan NP transfected B16 melanoma cells in C57BL/6 mice and delayed the growth of preinoculated melanoma cells. During the blockade of the tumor growth, the CTL response was maintained for at least approximately 6 weeks, and the mice secreted Th1 type cytokines such as IL-2 and IFN-gamma. These results suggested that the pH-sensitive liposomes might provide an effective peptide delivery system for CTL-mediated tumor therapy.

Nitrogen removal from sewage by continuous flow SBR system with intermittent aeration

A continuous-flow sequential batch reactor system with intermittent aeration known as the intermittent cycle extended aeration system was used to investigate the efficiencies of nitrogen removal for sewage. In the conventional intermittent cycle extend aeration system with continuous aeration process to treat the synthetic sewage wastewater under 3 cycles per day (cycle time = 8 hours), high COD removal efficiencies were achieved, but high levels of nitrate (22.3-23.6 mg l-1) and decreased pH values were also found in the effluent. In the intermittent aeration, the dissolved oxygen in the reactor was reduced from the range of 3.5-5.0 mg l-1 to 0.5-1.2 mg l-1, the nitrogen in the influent was partially oxidized to nitrite-nitrogen, although nitrate-nitrogen was also present in the effluent. In detailed cyclic study of the reactor with relatively low D.O. (0.3-1.0 mg l-1) and high MLSS (3200 mg l-1 at half full water level), the experimental results of intermittent aeration processes showed higher oxidation rates of ammonia to nitrite (1.44-3.55 mg N g-1 MLSS hr-1) than the conversion rates of nitrite to nitrate (0.00-1.22 mg N g-1 MLSS hr-1). It was thus, concluded that denitrification rates were not affected by the limited supplement of soluble organic carbon in the system. In addition, NOx(-)-N could be removed with a total nitrogen removal rate up to 94.9% when the MLSS was controlled in concentrations of 3200 mg l-1 at half full water level with low D.O. The process of intermittent aeration of ICEAS could provide an economic and effective means for nitrogen removal in treating sewage.

Biodegradation of phenanthrene in river sediment

The aerobic biodegradation potential of phenanthrene (a polycyclic aromatic hydrocarbon [PAH]) in river sediment was investigated in the laboratory. Biodegradation rate constants (k1) and half-lives (t1/2) for phenanthrene (5 microg/g) in sediment samples collected at five sites along the Keelung River in densely populated northern Taiwan ranged from 0.12 to 1.13 l/day and 0.61 to 5.78 day, respectively. Higher biodegradation rate constants were noted in the absence of sediment. Two of the sediment samples were capable of biodegrading phenanthrene at initial concentrations 5-100 microg/g; lower biodegradation rates occurred at higher concentrations. Optimal biodegradation conditions were determined as 30 degreesC and pH 7.0. Biodegradation was not significantly influenced by the addition of such carbon sources as acetate, pyruvate, and yeast extract, but was significantly influenced by the addition of ammonium, sulfate, and phosphate. Results show that anthracene, fluorene, and pyrene biodegradation was enhanced by the presence of phenanthrene, but that phenanthrene treatment did not induce benzo[a]pyrene biodegradation during a 12-day incubation period.

An autoregulatory feedback loop directs the localized expression of the Drosophila CPEB protein Orb in the developing oocyte

The RRM-type RNA binding protein Orb plays a central role in the establishment of polarity in the Drosophila egg and embryo. In addition to its role in the formation and initial differentiation of the egg chamber, orb is required later in oogenesis for the determination of the dorsoventral (DV) and anteroposterior (AP) axes. In DV axis formation, Orb protein is required to localize and translate gurken mRNA at the dorsoanterior part of the oocyte. In AP axis formation, Orb is required for the translation of oskar mRNA. In each case, Orb protein is already localized at the appropriate sites within the oocyte before the arrival of the mRNAs encoding axis determinants. We present evidence that an autoregulatory mechanism is responsible for directing the on site accumulation of Orb protein in the Drosophila oocyte. This orb autoregulatory activity ensures the accumulation of high levels of Orb protein at sites in the oocyte that contain localized orb message.

The unfolded protein response represses nitrogen-starvation induced developmental differentiation in yeast

Diploid budding yeast exhibits two developmental programs in response to nitrogen starvation, pseudohyphal growth, and sporulation. Here we show that both programs are repressed by activation of the unfolded protein response (UPR), a stress-signal transduction pathway responsible for induction of endoplasmic reticulum (ER)-resident chaperones when protein folding in the ER is impaired. Pseudohyphal growth was derepressed in ire1Delta/ire1Delta and hac1Delta/hac1Delta strains. Activation of the UPR or overexpression of the transcription factor Hac1(i)p, the product of an unconventional splicing reaction regulated by the UPR, was sufficient for repression of pseudohyphal growth and meiosis. HAC1 splicing occurred in a nitrogen-rich environment but ceased rapidly on nitrogen starvation. Further, addition of ammonium salts to nitrogen-starved cells was sufficient to rapidly reactivate HAC1 splicing. We propose that high translation rates in a nitrogen-rich environment are coupled to limited protein unfolding in the ER, thereby activating the UPR. An activated UPR then represses pseudohyphal growth and meiosis. Nitrogen starvation slows translation rates, allowing for more efficient folding of nascent polypeptide chains, down-regulation of the UPR, and subsequent derepression of pseudohyphal growth and meiosis. These findings significantly broaden the range of physiological functions of the UPR and define a role for the UPR in nitrogen sensing.

Frequency and characterization of platelet-specific antibodies in patients who received multiple platelet transfusions

BACKGROUND AND PURPOSE

Multiple platelet transfusions may induce alloimmunization. Platelet alloimmunization involves human leukocyte antigen (HLA) antibodies and platelet-specific antibodies, which recognize platelet glycoproteins. No data are available about the frequency and characteristics of platelet-specific antibodies in patients who have received multiple platelet transfusions in Taiwan.

METHODS

From June through December 1998, blood samples from 103 patients who had received multiple platelet transfusions were submitted to our laboratory for examination of platelet antibodies. The samples were first screened for HLA antibodies or platelet-specific antibodies using a solid phase method. Positive sera were further tested using an enzyme-linked immunosorbent assay (ELISA) to identify the specificities of the alloantibodies.

RESULTS

Forty of the 103 patients who had received multiple platelet transfusions were positive for platelet-reactive antibodies. Further study using ELISA showed that 22 patients had both HLA and platelet-specific antibodies, 12 patients had HLA antibodies alone, and five patients produced platelet-specific antibodies in the absence of HLA antibodies. Most platelet-specific antibodies were found among patients who had HLA antibodies: 81% of platelet-specific antibodies were found in HLA-immunized patients. The most frequently involved platelet glycoprotein antigens were Ia/IIa and IIb/IIIa.

CONCLUSIONS

HLA antibodies were the most frequently found platelet-reactive antibodies in Taiwanese patients who had received multiple transfusions, although platelet-specific antibodies were also common. The frequency of platelet-specific antibodies was not as low as previously reported.

Evaluation of pharmacokinetics and pharmacodynamics of captopril from transdermal hydrophilic gels in normotensive rabbits and spontaneously hypertensive rats

The purpose of this investigation was to assess the pharmacokinetics (plasma concentration) and pharmacodynamics (heart rate, blood pressure (BP), and plasma renin activity (PRA)) of captopril experimental gel in normotensive rabbits and spontaneously hypertensive rats (SHRs) by reference to a short duration intravenous administration of the drug. In normotensive rabbits, the blood concentration versus time course of captopril after transdermal administration could be described well by a two-compartment model, and the maximum plasma concentration (5. 68+/-2.05 microg ml(-1)) was achieved in about 7 h. The increase in plasma captopril concentration led to increases in PRA and reductions in BP. A simple E(max) model adequately described the relationship between the percentage change of mean blood pressure (MBP) and the blood concentration of the captopril. The maximum reduction in MBP (E(max)) was 36.23% and the concentration at half maximum effect (EC(50)) was 0.24 microg ml(-1). The captopril was continuously released from the gel formulation and protected the SHRs in lower BP throughout the period of transdermal therapy. These results indicated that the development of captopril transdermal drug delivery system was possible. Further research was warranted on a modified formulation of captopril, which was optimized for transdermal delivery of the drug.

Elevation of the gamma-aminobutyric acid transaminase expression in the gerbil CA1 area after ischemia-reperfusion damage

gamma-Aminobutyric acid-transaminase (GABA-T) plays an important role in the metabolism of GABA, particularly in the neurons or glial cells. The present study was undertaken to determine the alteration of GABA-T expression in the gerbil hippocampus after ischemia-reperfusion. In the sham, GABA-T(+) neurons were scattered in the hippocampus proper and dentate gyrus. The intensity of the GABA-T immunoreactivity had nearly disappeared in the interneurons at 12 h after ischemia. In contrast, 24 h post-ischemia the dramatic augmentation of GABA-T immunoreactivity in the pyramidal cells was observed in the CA1 area but not in the CA2 or CA3 areas. Forty-eight hours after ischemia-reperfusion, its immunoreactivity was preserved in the CA1 neurons. These results suggest that the over-expression of GABA-T in the CA1 area may be related to delayed neuronal death after ischemia-reperfusion insult.

Fed-batch bioreactor strategies for microbial decolorization of azo dye using a Pseudomonas luteola strain

A Pseudomonas luteola strain possessing azoreductase activity was utilized to decolorize a reactive azo dye (C. I. Reactive Red 22) with fed-batch processes consisting of an aerobic cell growth stage and an anaerobic fed-batch decolorization stage. The fed-batch decolorization was conducted with different agitation and aeration rates, initial culture volumes, dye loading strategies, and yeast extract to dye (Y/D) ratios, and the effect of those operation parameters on azo dye decolorization was evaluated. Dissolved oxygen strongly inhibited the azo reduction activity; thus aeration should be avoided during decolorization but slight agitation (around 50 rpm) was needed. With the periodical feeding strategy, the specific decolorization rate (v(dye)) and overall decolorization efficiency (eta(dye)) tended to increase with increasing feeding concentrations of dye, whereas substrate inhibition seems to arise when the feeding concentration exceeded 600 mg dye/L. In the continuous feeding mode, higher initial culture volume resulted in better eta(dye) due to higher biomass loading, but lower v(dye) due to lower dye concentration in the bioreactor. With a volumetric flow rate (F) of 25 mL/h, both v(dye) and eta(dye) increased almost linearly with the increase in the loading rate of dye (F(dye)) over the range of 50-200 mg/h, while further increase in F(dye) (400 mg/h) gave rise to a decline in v(dye) and eta(dye). As the F was doubled (50 mL/h), the v(dye) and eta(dye) increased with F(dye) only for F(dye) < 80 mg/h. The best v(dye) (113.7 mg dye g cell(-)(1) h(-)(1)) and eta(dye) (86.3 mg dye L(-)(1) h(-)(1)) were achieved at F(dye) = 200 mg/h and F = 25 mL/h. The yield coefficient representing the relation between dye decolorized and yeast extract consumed was estimated as 0.8 g/g. With F(dye) = 75 mg/h, the Y/D ratio should be higher than 0.5 to ensure sufficient supply of yeast extract for stable fed-batch operations. However, performance of the fed-batch decolorization process was not appreciably improved by raising the Y/D ratio from 0.5 to 1.875 but was more sensitive to the changes in the dye loading rate.

The short-term effect of pentoxifylline on rabbit choroidal blood flow

This study evaluates the effect of different doses ofpentoxifylline on rabbit choroidal blood flow (CBF). Sixteen albino rabbits of both sexes, weighing 2.0-3.0 kg, were randomly separated into four groups. The first group of rabbits received 2 ml normal saline injection through the ear vein. They served as the control group (group n). Three different doses of pentoxifylline, 1 mg/kg, 5 mg/kg, and 10 mg/kg, were injected intravenously to groups p1, p5 and p10, respectively. By means of a laser Doppler flowmeter, the blood cell flux (PF), velocity, and the concentration of moving blood cells (CMBC) were recorded simultaneously. The laser probe was advanced through the pars plana and positioned near the retinal surface. The mean arterial pressure was recorded at the same time. There was a significant increase in PF at 1, 5 and 10 min in group p10 rabbits compared with the control group (p=0.0005, 0.0416, and 0.0087, respectively). The velocity increased at 5 min in group p5 rabbits (p=0.0082) and at 1, 5 and 10 min in group p10 rabbits (p=0.0188, 0.0080, and 0.0207, respectively) as compared with the controls. The CMBC decreased after injection of pentoxifylline and reached statistical significance at 5 and 10 min in group p5 rabbits (p=0.0019 and 0.0046, respectively) and at 5 min in group p10 rabbits (p=0.0447). These results show that larger doses of pentoxifylline (10 mg/kg) increased the CBF of rabbits. This effect was achieved primarily by an increase in blood cell velocity.

Identification of a U2/U6 helix la mutant that influences 3' splice site selection during nuclear pre-mRNA splicing

Base substitutions in U2/U6 helix I, a conserved base-pairing interaction between the U6 and U2 snRNAs, have previously been found to specifically block the second catalytic step of nuclear pre-mRNA splicing. To further assess the role of U2/U6 helix I in the second catalytic step, we have screened mutations in U2/U6 helix I to identify those that influence 3' splice site selection using a derivative of the yeast actin pre-mRNA. In these derivatives, the spacing between the branch site adenosine and 3' splice site has been reduced from 43 to 12 nt and this results in enhanced splicing of mutants in the conserved 3' terminal intron residue. In this context, mutation of the conserved 3' intron terminal G to a C also results in the partial activation of a nearby cryptic 3' splice site with U as the 3' terminal intron nucleotide. Using this highly sensitive mutant substrate, we have identified a mutation in the U6 snRNA (U57A) that significantly increases the selection of the cryptic 3' splice site over the normal 3' splice site and augments its utilization relative to that observed with the wild-type U2 or U6 snRNAs. In a previous study, we found that the same U6 mutation suppressed the effects of an A-to-G branch site mutation in an allele-specific fashion. The ability of U6-U57 mutants to influence the fidelity of both branch site and 3' splice site recognition suggests that this nucleotide may participate in the formation of the active site(s) of the spliceosome.

Direct interaction of SOS1 Ras exchange protein with the SH3 domain of phospholipase C-gamma1

A recent report that microinjection of the SH3 domain of PLC-gamma1 could induce DNA synthesis raised the functional importance of the SH3 domain of PLC-gamma1 in mitogenic signaling. In this report, we provide evidence that SOS1, a p21Ras-specific guanine nucleotide exchange factor, directly binds to the SH3 domain of PLC-gamma1, and that the SH3 domain of PLC-gamma1 is involved in SOS1-mediated p21Ras activation. SOS1 was coprecipitated with the GST-fused SH3 domain of PLC-gamma1 in vitro. The interaction between SOS1 and the PLC-gamma1 SH3 domain is mediated by direct physical interaction. The carboxyl-terminal proline-rich domain of SOS1 is involved in the interaction with the PLC-gamma1 SH3 domain. Moreover, PLC-gamma1 could be co-immunoprecipitated with SOS1 antibody in cell lysates. From transient expression studies, we could demonstrate that the SH3 domain of PLC-gamma1 is necessary for the association with SOS1 in vivo. Intriguingly, overexpression of the SH3 domain of PLC-gamma1, lipase-inactive PLC-gamma1, or wild-type PLC-gamma1 elevated p21Ras activity and ERK activity when compared with vector transfected cells. The PLC-gamma1 mutant lacking the SH3 domain could not activate p21Ras. p21Ras activities in cell lines overexpressing either PLC-gamma1 or the SH2-SH2-SH3 domain of PLC-gamma1 were elevated about 2-fold compared to vector transfected cells. This study is the first to demonstrate that the PLC-gamma1 SH3 domain enhances p21Ras activity, and that the SH3 domain of PLC-gamma1 may be involved in the SOS1-mediated signaling pathway.

Transplant of cultured autologous pure melanocytes after laser-abrasion for the treatment of segmental vitiligo

Segmental vitiligo is a special type of vitiligo with unilateral distribution of lesions and has a stable course. Clinically, many patients with segmental vitiligo have unsatisfactory responses to topical corticosteroid or UV phototherapy. We have developed a technique for the isolation of melanocytes from a small specimen of normally pigmented skin obtained via a suction blister. The melanocytes can be proliferated in culture and then replanted onto laser-abrased vitiliginous areas. We used this procedure to treat 25 patients with segmental vitiligo that were refractory to medical therapy. The repigmented portion of the total treated area amounted to 95-100% in 21 patients and 65 to 94% in 4 patients. The response rate to treatment was 100% in this study. No scarring or other side-effects developed. The results of this study demonstrate that this method is a valuable tool for the treatment of patients with segmental vitiligo.

Linear free energy relationships implicate three modes of binding for fluoroaromatic inhibitors to a mutant of carbonic anhydrase II

[figure: see text] Linear free energy relationships between binding affinity and hydrophobicity for a library of fluoroaromatic inhibitors of F131V carbonic anhydrase II (CA) implicate three modes of interaction. X-ray crystal structures suggest that F131 interacts with fluoroaromatic inhibitors, while P202, on the opposite side of the active site cleft, serves as the site of the hydrophobic contact in the case of the F131V mutant. 2-Fluorinated compounds bind more tightly, perhaps due to the field effect of the nearby fluorine on the acidity of the amide proton.

History of the Korean GLPs and the activities and perspectives of the Korean Society of GLP

The Korean Society of Good Laboratory Practice (KSGLP) was established Dec. 10, 1998. The objectives of the KSGLP are to enhance the quality of domestic studies and the level of GLP compliance, in safety testing, and to promote information exchange among its members. The activities of KSGLP include: offering workshops and symposiums, linking with related governmental organizations, collecting GLP related information and providing the information to the related organizations, building international networks to collect information and to establish relationship, developing training materials and publishing periodicals, and other business necessary to achieve the objectives of the KSGLP. The KSGLP achieved its goals within a short period of time by offering workshops and symposia, and by providing important GLP related information in newspapers or via the KSGLP's internet homepage (www.ksglp.or.kr). The main role of the KSGLP will be to disseminate GLP technology nationwide. The KSGLP would like to help many labs that are preparing their facilities for GLP compliance. Further, the KSGLP is hoping to share GLP experiences with other members.

The SH2-SH2-SH3 domain of phospholipase C-gamma1 directly binds to translational elongation factor-1alpha

Phospholipase C-gamma1 (PLC-gamma1) is a lipase that hydrolyzes PIP2 to generate two second messengers, IP3 and DAG. By using the yeast two-hybrid system, we identified the translational elongation factor-1alpha (EF-1alpha) as a binding protein of PLC-gamma1 from the human B-lymphocyte library. Direct interaction between EF-1alpha and PLC-gamma1 was confirmed by the in vitro binding experiment using purified PLC-gamma1. Furthermore, from the in vitro binding experiment, we could demonstrate that the carboxyl terminal region of EF-1alpha is involved in the interaction with PLC-gamma1, and that both SH2 and SH3 domains of PLC-gamma1 are required for the interaction with EF-1alpha. In vivo interaction between EF-1alpha and PLC-gamma1 was confirmed by the immunoprecipitation experiment using anti-EF-1alpha antibody. The interaction between EF-1alpha and PLC-gamma1 was enhanced by EGF-treatment. Taken together, we suggest that EF-1alpha might play a role in PLC-gamma1-mediated signal transduction.

The Drosophila CPEB homolog, orb, is required for oskar protein expression in oocytes

The establishment of polarity axes in the Drosophila egg and embryo depends upon the localization and on-site expression of maternal mRNAs. The critical step in the targeting of posterior determinants is the localization of oskar (osk) mRNA to the pole and its on-site translation. Osk protein then recruits other posterior group gene products involved in the formation of pole plasm and in the localization and regulation of the posterior determinant, nanos. Here we have investigated the role of the Drosophila CPEB homolog, the orb gene, in the osk mRNA localization pathway. We demonstrate that the expression of Osk protein is dependent upon the orb gene. In strong orb mutants, Osk protein expression is undetectable, while in the hypomorphic mutant, orb(mel), little or no on-site expression of Osk protein at the posterior pole is observed. The defects in Osk protein accumulation in orb mutant ovaries are correlated with a reduction in the length of the osk poly(A) tails. We show that osk mRNA is in immunoprecipitable complexes with Orb protein in ovaries and that the osk 3' UTR can be UV cross-linked to Orb protein in ovarian extracts. These data suggest that Orb is required to activate the translation of osk mRNA and at that this may be accomplished by a mechanism similar to that used by the Xenopus CPEB protein to control translation of "masked" mRNAs.

Transformation of rat fibroblasts by phospholipase C-gamma1 overexpression is accompanied by tyrosine dephosphorylation of paxillin

We previously have shown that the overexpression of phospholipase C-gamma1 (PLC-gamma1) in rat 3Y1 fibroblasts results in malignant transformation (Chang, J.-S., Noh, D.Y., Park, I.A., Kim, M;.J., Song, H., Ryu, S.H. and Suh, P.-G. (1997) Cancer Res. 57, 5465-5468). The transformed cells, which initially are in an elongated and flat form after seeding in plastic dishes, become rounded during continued culture. We found that tyrosine dephosphorylation of paxillin accompanies this morphological change of the transformed cells and that PLC-gamma1 co-immunoprecipitates together with paxillin and vice versa, but not after the cells have become round. Transformed cells growing on fibronectin-pre-coated dishes regain their flat morphology and this is accompanied by paxillin tyrosine phosphorylation. Furthermore, immunoprecipitation analysis showed that paxillin forms a heteromeric complex with PLC-gamma1 in cells grown on fibronectin. These results suggest that a complex formation between paxillin and PLC-gamma1 may play a role in cell-substrate adhesion.

The anesthetic management of a preterm infant weighing 500 grams undergoing ligation of patent ductus arteriosus--a case report

PDA (patent ductus arteriosus) is a common congenital heart disease. Usually surgical intervention through left thoracotomy or recently through video assisted thoracoscopy will be recommended if the preceding or intent medical treatment fails or is contraindicated. However, once surgical intervention is decided, various complications are still a real fear in the mind of the surgeon and the anesthesiologist, particularly if the infant is premature or very sick. Here we report an anesthetic management in a female preterm infant weighing 500 grams, who underwent PDA ligation. She was born at gestation age of 28 weeks at our hospital, and since her birth she was noted to have infant respiratory distress syndrome associated with renal dysfunction. She was admitted to the neonatal intensive care unit (NICU) straightaway. After thorough examination, a severe PDA was disclosed. The possibility of pulmonary hemorrhage and heart failure could be predicted in view of the large left to right shunt. Worst of all was that her poor renal function contradicted a medical treatment. So we decided to carry out the ligation procedure at once although she was premature and only 5 days old. The NICU was chosen as the operation theater for transferring concerns. General anesthesia was induced and maintained by atropine 0.01 mg, pancuronium 0.1 mg, fentanyl 2 micrograms, and ketamine 0.15 mg intravenously. Supplemental oxygen was given throughout the operation. The PDA was ligated through left thoracotomy and blood loss was minimal. The peri-operative course was uneventful. The patient recovered well following surgery and anesthesia.

Immunogenicity of synthetic HIV-1 V3 loop peptides by MPL adjuvanted pH-sensitive liposomes

A successful HIV-1 vaccine should be capable of generating humoral and cellular immune responses at the same time. The only response shown to be effective in this regard is virus-neutralization antibodies and virus-specific cytotoxic T-lymphocytes (CTL) directed against the viral antigens. In the present study, it is shown that V3 peptides encapsulated pH-sensitive liposomes elicit the virus neutralization antibodies and virus specific CTL response at the same time in Balb/c mice. None of the immunization protocols elicited an antibody response and CTL response when R15K and T26K was used as immunogen without liposomes. In contrast, antibodies and CTL response were detectable in the mice which were immunized with peptide encapsulated pH-sensitive liposomes. Antibody production was confirmed by virus neutralizing assay. CD4+ T-cells are involved in target cell lysis to some degree but CTL activity is mainly due to the CD8 + T-cells. The consistency of the antibody and CTL response was related to the V3 loop peptides size. The T26K (26mer) peptide induced a stronger antibody and CTL response than R15K (15mer) in vivo. Based on the results of this study, T26K was used as a potentially effective HIV-1 vaccine component and T26K encapsulated pH-sensitive liposomes composed of phosphatidylethanolamine-beta-oleoyl-gamma-palmitoyl (POPE)/cholesterol hemisuccinate (CHOH)/monophosphoryl lipid A (MPL) (7:3:0.1, mole ratio) may be used as a potentially immunomodulating adjuvant system for the development of HIV and other viral vaccines.