Attosecond angle-resolved photoelectron spectroscopy

We report experiments on the characterization of a train of attosecond pulses obtained by high-harmonic generation, using mixed-color (XUV+IR) atomic two-photon ionization and electron detection on a velocity map imaging detector. We demonstrate that the relative phase of the harmonics is encoded both in the photoelectron yield and the angular distribution as a function of XUV-IR time delay, thus making the technique suitable for the detection of single attosecond pulses. The timing of the attosecond pulse with respect to the field oscillation of the driving laser critically depends on the target gas used to generate the harmonics.

Construction and characterization of a recombinant ovine lentivirus carrying the optimized green fluorescent protein gene at the dUTPase locus

AdUTPase gene ( du) deleted ovine lentivirus (OvLV(Deltadu)) mutant, derived from Visna/maedi virus (VMV) molecular clone KV1772, was constructed. Subsequently, a copy of the optimized green fluorescent protein ( egfp) coding region was fused into the viral pol open reading frame (ORF) at the deleted du locus to generate viral mutant, OvLV(Deltadu-egfp). OvLV(Deltadu) reverse transcriptase (RT) activity and titer of infectious virus in goat synovial membrane (GSM) cell cultures were not affected compared to that of KV1772 and OvLV-85/34 strain (p < 0.05). By contrast, OvLV(Deltadu-egfp) RT activity and virus titer were lower than for KV1772 and OvLV(Deltadu) (p < 0.05). OvLV-85/34 RT in sheep monocyte-derived macrophages (SMDM) was higher than that of KV1772, OvLV(Deltadu) and OvLV(Deltadu-egfp) (p < 0.05). The ability to prevent dUTP mis-incorporation into newly synthesized DNA was disrupted in OvLV(Deltadu) and OvLV(Deltadu-egfp) (p < 0.05). Immunoprecipitation demonstrated that GFP is expressed by OvLV(Deltadu-egfp) at a low level. OvLV(Deltadu-egfp) retained egfp after 10 passages in cell culture.OvLV(Deltadu-egfp) was re-isolated in GSM cells from peripheral blood mononuclear (PBMN) cells of three of four OvLV(Deltadu-egfp)-inoculated lambs, but by contrast to the in vitro experiments OvLV(Deltadu-egfp) lost the insert. Priming with OvLV(Deltadu-egfp) did not prevent infection with pathogenic OvLV, but cell-associated viremia in a mock-infected contact control lamb was higher than in OvLV(Deltadu-egfp)-primed lambs. OvLV serum antibody titers increased steadily in OvLV(Deltadu-egfp)-inoculated lambs, but in a lamb from which OvLV(Deltadu-egfp) was not reisolated the antibody titer surpassed the negative/positive cut-off value only after challenge with OvLV-85/34. Because OvLV(Deltadu-egfp) is attenuated for pathogenicity in vitro, replicates in vivo and stimulates an antibody response, subsequent experiments need to address the likelihood of using OvLV(Deltadu-egfp) as an attenuated, live-virus vaccine to protect sheep against OvLV-induced disease when challenged with pathogenic OvLV.

[Anti-hemolytic and anti-membranous lipid peroxidation effects of daphnetin]

AIM

To investigate the anti-hemolytic and anti-membranous lipid peroxidation effects of daphnetin.

METHODS

The inhibition rates of daphnetin on AQD-induced hemolysis and erythrocytic membranous lipid peroxidation were determined by routine in vitro assay for detecting hemolytic toxicity and by HPLC for detecting membranous lipid peroxidation products.

RESULTS

Daphnetin at a range of 10-80 mumol/L inhibited dose-dependently AQD-induced hemolysis and lipid peroxidation by 33.0%-69.2% and 11.9%-58.2%, respectively.

CONCLUSION

Daphnetin has anti-hemolytic and anti-erythrocytic membranous lipid peroxidation effects.

[Studies on dynamic changes of SOD and MDA in cultured cells from Schistosoma japonicum schistosomula]

AIM

To observe the dynamic changes of superoxide dismutase(SOD) and maldondialdehyde(MDA) in cultured cells from Schistosoma japonicum schistosomula and to explore the degeneration process of cultured cells.

METHODS

Pyrogallol method and thiobarbituric acid method were used to determinate the levels of SOD and MDA, respectively, in the cells cultured for 0-54 days.

RESULTS

SOD in the cells reached a peak level on d12 of the early stage of culture and then decreased. The MDA levels in the cultures cells ascended gradually, and had two peaks on d18 and d48, during the period of culture.

CONCLUSION

The cultured cells from S. japonicum schistosomula degenerated progressively.

Complications of radiofrequency coagulation of liver tumours

BACKGROUND

Radiofrequency coagulation (RFC) is being promoted as a novel technique with a low morbidity rate in the treatment of liver tumours. The purpose of this study was to assess critically the complication rates of RFC in centres with both large and limited initial experience, and to establish causes and possible means of prevention and treatment.

METHODS

This is an exhaustive review of the world literature (articles and abstracts) up to 31 December 2001; 82 independent reports of RFC of liver tumours were analysed.

RESULTS

In total, 3670 patients were treated with percutaneous, laparoscopic or open RFC. The mortality rate was 0.5 per cent. Complications occurred in 8.9 per cent: abdominal bleeding in 1.6 per cent, abdominal infection in 1.1 per cent, biliary tract damage in 1.0 per cent, liver failure in 0.8 per cent, pulmonary complications in 0.8 per cent, dispersive pad skin burn in 0.6 per cent, hepatic vascular damage in 0.6 per cent, visceral damage in 0.5 per cent, cardiac complications in 0.4 per cent, myoglobinaemia or myoglobinuria in 0.2 per cent, renal failure in 0.1 per cent, tumour seeding in 0.2 per cent, coagulopathy in 0.2 per cent, and hormonal complications in 0.1 per cent. The complication rate was 7.2, 9.5, 9.9 and 31.8 per cent after a percutaneous, laparoscopic, simple open and combined open approach respectively. The mortality rate was 0.5, 0, 0 and 4.5 per cent respectively.

CONCLUSION

The morbidity and mortality of RFC, while low, is higher than previously assumed. With adequate knowledge, many complications are preventable.

New approach for preparation of 2,3,7-trisubstituted 3,4-dihydroisoquinolinone libraries on solid phase

In an attempt to prepare 7-substituted 3,4-dihydroisoquinolinone family of compounds, we observed an unexpected decarboxylation. The reaction of 4-nitrohomophthalic anhydride with a Schiff base formed on solid support leads to the formation of core structure. LC-MS and 1H NMR analysis confirmed the structure of unexpected intermediate. A library of 38,400 compounds was produced using this new synthetic approach.

An ex vivo study on radiofrequency tissue ablation: increased lesion size by using an "expandable-wet" electrode

The present comparative study was conducted to validate a newly developed "expandable-wet" electrode for an increased lesion size of radiofrequency ablation (RFA) on excised beef liver. The expandable-wet electrode, which allows interstitial hypertonic saline infusion through retractable curved needles, was compared with "expanded-dry" and "unexpanded-wet" electrodes for RFA lesion size and other parameters. A total of 120 lesions were created under 50 W (groups A-C) and 90 W (groups A'-C') power control mode for 10 min at each ablation site with the following groups: group A and A' of expanded-dry electrode (needles deployed but saline uninfused); group B and B' of unexpanded-wet electrode (saline infused but needle undeployed); and group C and C' of expanded-wet electrode (needles deployed and saline infused). Together with lower impedance and higher power output, the lesion size in group C (5.3+/-0.4 cm) and C' (6.0+/-1.0 cm) were significantly larger (P<0.01) than that in group A (3.3+/-0.3 cm) and A' (2.0+/-0.2 cm), and group B (3.8+/-1.0 cm) and B' (2.6+/-0.4 cm). The RFA lesion size can be significantly enlarged when the expandable electrode is complemented with interstitial hypertonic saline infusion. This design may improve the efficacy of RF tumor ablation.

Radiofrequency ablation for eradication of renal tumor in a rabbit model by using a cooled-tip electrode technique

BACKGROUND

Radiofrequency ablation (RFA) has emerged as a potential alternative for surgery in clinical oncology. This animal experiment was conducted to evaluate the feasibility of RFA in the treatment of renal tumor.

METHODS

Eighteen rabbits with renal implantation of VX2 tumors were divided into two groups. Group A (n = 12) was treated with RFA by using a cooled-tip RF system at 30 W for 80 to 180 seconds. Group B (n = 6) received a sham operation. The therapeutic efficacy was evaluated by survival rate, magnetic resonance imaging (MRI), and histology.

RESULTS

All animals in group B died within 3 months after tumor implantation. Total tumor eradication was achieved in 10 of 12 rabbits (83.3%) in group A, of which 5 rabbits survived longer than 6 months (absolute eradication) and another 5 rabbits were found free of viable tumor when killed (relative eradication). Two rabbits experienced local tumor relapse, lung metastasis, or both. Six-month survival rate of RFA-treated rabbits was significantly higher (P < .01) than that of control rabbits. The typical MRI appearances of the acute RFA lesion consisted of five characteristic concentric zones, which corresponded to central needle track (zone A), tumor coagulation (zone B), renal tissue coagulation (zone C), peripheral hemorrhage (zone D), and inflammatory layer (zone E) on histology.

CONCLUSIONS

RFA may become a promising therapy for the treatment of renal tumor. MRI is a useful modality for assessment of renal tumor ablation.

Radiofrequency ablation for eradication of pulmonary tumor in rabbits

BACKGROUND

Radiofrequency ablation (RFA) has emerged as an alternative for surgery in clinical oncology. This animal experiment was conducted to evaluate the feasibility of RFA in the treatment of pulmonary tumor.

METHODS

Eighteen rabbits with pulmonary implantation of VX2 tumors were divided into two groups. Group A (n = 12) was treated with RFA by using a cooled-tip electrode technique. Group B (n = 6) received sham operation. The therapeutic efficacy was evaluated by survival rate, magnetic resonance imaging (MRI), postmortem microangiography, and histology.

RESULTS

All animals in group B died within 3 months after tumor implantation. Tumor eradication was achieved in 9 of 12 rabbits (75.0%) in group A, of which 4 rabbits survived longer than 3 months free of disease and another 5 rabbits were found free of viable tumor when sacrificed. One rabbit was subjected to incomplete tumor ablation and two rabbits suffered from local tumor relapse and/or lung metastasis. The 3-month survival rate of RFA-treated rabbits was significantly higher (P < 0.01) than that of control rabbits. The typical MRI appearances of the acute RFA lesion consisted of five characteristic concentric zones, which corresponded to central needle track (zone A), tumor coagulation (zone B), pulmonary parenchyma coagulation (zone C), peripheral hemorrhage (zone D), and inflammatory layer (zone E) on histology.

CONCLUSIONS

Eradication of pulmonary tumor could be achieved with current RFA technique in rabbits. MRI is a useful modality for assessment of lung tumor ablation.

Evidence that NADP+ is the physiological cofactor of ADP-L-glycero-D-mannoheptose 6-epimerase

ADP-L-glycero-D-mannoheptose 6-epimerase is required for lipopolysaccharide inner core biosynthesis in several genera of Gram-negative bacteria. The enzyme contains both fingerprint sequences Gly-X-Gly-X-X-Gly and Gly-X-X-Gly-X-X-Gly near its N terminus, which is indicative of an ADP binding fold. Previous studies of this ADP-l-glycero-D-mannoheptose 6-epimerase (ADP-hep 6-epimerase) were consistent with an NAD(+) cofactor. However, the crystal structure of this ADP-hep 6-epimerase showed bound NADP (Deacon, A. M., Ni, Y. S., Coleman, W. G., Jr., and Ealick, S. E. (2000) Structure 5, 453-462). In present studies, apo-ADP-hep 6-epimerase was reconstituted with NAD(+), NADP(+), and FAD. In this report we provide data that shows NAD(+) and NADP(+) both restored enzymatic activity, but FAD could not. Furthermore, ADP-hep 6-epimerase exhibited a preference for binding of NADP(+) over NAD(+). The K(d) value for NADP(+) was 26 microm whereas that for NAD(+) was 45 microm. Ultraviolet circular dichroism spectra showed that apo-ADP-hep 6-epimerase reconstituted with NADP(+) had more secondary structure than apo-ADP-hep 6-epimerase reconstituted with NAD(+). Perchloric acid extracts of the purified enzyme were assayed with NAD(+)-specific alcohol dehydrogenase and NADP(+)-specific isocitric dehydrogenase. A sample of the same perchloric acid extract was analyzed in chromatographic studies, which demonstrated that ADP-hep 6-epimerase binds NADP(+) in vivo. A structural comparison of ADP-hep 6-epimerase with UDP-galactose 4-epimerase, which utilizes an NAD(+) cofactor, has identified the regions of ADP-hep 6-epimerase, which defines its specificity for NADP(+).

Akt/protein kinase B is constitutively active in non-small cell lung cancer cells and promotes cellular survival and resistance to chemotherapy and radiation

To evaluate the role of Akt/PKB in non-small cell lung cancer (NSCLC) survival, we analyzed NSCLC cell lines that differed in tumor histology as well as p53, Rb, and K-ras status. Constitutive Akt/protein kinase B (PKB) activity was demonstrated in 16 of 17 cell lines by maintenance of S473 phosphorylation with serum deprivation. Additional analysis of five of 2these NSCLC lines revealed that phosphorylation of S473 and T308 correlated with in vitro kinase activity. Akt/PKB activation was phosphatidylinositol 3-kinase-dependent and promoted survival because the phosphatidylinositol 3 inhibitors LY294002 and wortmannin inhibited Akt/PKB phosphorylation, Akt/PKB activity, and increased apoptosis only in cells with active Akt/PKB. To test whether Akt/PKB activity promoted therapeutic resistance, LY294002 was added with individual chemotherapeutic agents or irradiation. LY294002 greatly potentiated chemotherapy-induced apoptosis in cells with high Akt/PKB levels, but did not significantly increase chemotherapy-induced apoptosis in cells with low Akt/PKB levels. Combined with radiation in cells with active Akt/PKB, LY294002 additively increased apoptosis and inhibited clonogenic growth. These results were extended with transiently transfected Akt/PKB mutants. Transfecting dominant negative Akt/PKB decreased Akt/PKB activity and increased basal apoptosis as well as chemotherapy- and irradiation-induced apoptosis only in cells with high Akt/PKB activity. Conversely, transfecting constitutively active Akt/PKB into cells with low Akt/PKB activity increased Akt/PKB activity and attenuated chemotherapy- and radiation-induced apoptosis. We therefore identify Akt/PKB as a constitutively active kinase that promotes survival of NSCLC cells and demonstrate that modulation of Akt/PKB activity by pharmacological or genetic approaches alters the cellular responsiveness to therapeutic modalities typically used to treat patients with NSCLC.

Intracoronary delivery of Gd-DTPA and Gadophrin-2 for determination of myocardial viability with MR imaging

The aim of this study was to compare intracoronary (i.c.) administration of Gadophrin-2, a necrosis-avid contrast agent (NACA), and nonspecific agent Gd-DTPA for determination of myocardial viability (MV) in acute myocardial infarction (AMI) with MRI. Reperfused AMI was induced in 12 dogs by transcatheter balloon occlusion of coronary artery. In 6 dogs each, Gd-DTPA at 0.1 mmol/kg or Gadophrin-2 at 0.005 mmol/kg was administered into coronary artery by fast bolus (n = 3) or slow infusion (n = 3). Serial ECG-triggered cardiac MRI of T1-weighted segmented turbo fast low-angle shot (FLASH) sequence was conducted and compared with triphenyltetrazolium chloride (TTC) histochemical staining. The contrast ratio and infarct size were quantified and analysed statistically. No cardiovascular side effects were found with local delivery of both agents. After i.c. administration, Gadophrin-2 induced a strong (CR > or = 1.78) and persistent (> or = 10 h) contrast enhancement of infarcted region. The infarct size defined with Gadophrin-2 was almost identical to that with TTC staining throughout the postcontrast period. With a dose 20 times higher, Gd-DTPA also strongly enhanced infarct-to-normal contrast; however, the enhancement diminished with time, i.e. from early strong to later faint enhancement and eventual loss of contrast. The delineated infarct size was also unstable, i.e. from early overestimation to later underestimation and eventual disappearance of the enhanced infarct. In combination with PTCA procedure, i.c. administration of MRI contrast agents may prove useful for post-procedure verification of diagnosis. The NACA-enhanced MRI may serve as an in vivo surrogate of postmortem histochemical staining for determination of MV. Although applicable in clinical setting, cardiac MRI with nonspecific Gd-DTPA is less reliable and should be performed within less than 1 h after contrast.

[Micro -- ecological investigation of burn wound infection]

OBJECTIVE

To analyze the epidemic tendency of the bacteria causing burn wound infection, and to explore the influencing factors.

METHODS

Bacterial ecology on burn wound was investigated in 210 cases of burn patients admitted to our hospital from January 1999 to December 2000, and the results were compared to those done in the 1970s, 1980s and 1990s.

RESULTS

Since 1999, G(+)cocci increased obviously (52.17%) when compared with those of the past three decades (P < 0.01), while G(minus sign) bacilli decreased significantly (46.48%, P < 0.01). The ratio of Pseudomonas aeruginosa in recent two years was evidently lower than those in the early 1970s and 1990s (P < 0.01) while the ratio of staphylococcus aureus was much higher than those in the middle of 1980s and 1990s (P < 0.01), in which methacillin -- resistant Staphylococcus aureus (MRSA) accounted for 85% or so, which increased significantly than those in the middle of 1980s and the beginning of 1990s (P < 0.01) with an increasing tendency.

CONCLUSION

The increasing tendency of Staphylococcus aureus in our unit for the recent two years might closely be related to the preferential application of Imipenem in burn infection control. Furthermore, the ratio of MRSA in Staphylococcus aureus could not be lowered by vancomycin.

[Preferential flow and its effect on solute migration in soil]

The characteristics of soil preferential flow and the preferential migrate in soil for non-absorptive bromide and nitrate ions were studied. With undisturbed and packed soil columns, the results showed that soil preferential flow was characterized with preferential breakthrough, non-symmetric breakthrough curve, lateral infiltration, tailing and so on. The preferential breakthrough for Br- was 24 hours after it was applied, and the leachate volume was only 0.04 times as-much as the pore volumes. The preferential flow for Br- accounted for 26% of total flux in the undisturbed soil columns. But the accumulative leachate mass for Br- resulted from the preferential flow were 86.7% of total accumulative leachate mass, showing that the soil preferential flow accounted for relative small ratio of the flux, but caused relative much more solute transference. NO3- was moved down rapidly by preferential flow at only one time as large as pore volumes, and got 11% of the applied amount, respectively. As a result of the preferential flow, the lateral infiltration flow enabled Br- and NO3- rapidly distribute and diffuse into the deeper soil.

MRI contrast enhancement of necrosis by MP-2269 and gadophrin-2 in a rat model of liver infarction

RATIONALE AND OBJECTIVES

The mechanisms of action leading to specific localization of necrosis-avid contrast agents (NACAs) such as gadophrin-2 are not well defined. It has been suggested recently that agents with a high degree of serum albumin binding may also serve as NACAs by virtue of nonspecific hydrophobic interactions. The present MRI-histomorphology correlation study was conducted to verify the likelihood of the proposed albumin-binding mechanism by comparing an albumin-binding blood pool agent, MP-2269, with gadophrin-2 in a rat model of reperfused liver infarction.

METHODS

Reperfused infarction in the right liver lobe was surgically induced in six rats. Serial T1-weighted MRI was performed before and after intravenous injection of MP-2269 at 0.05 mmol/kg and repeated in the same rats 24 hours later after intravenous injection of gadophrin-2 at the same dosage (0.05 mmol/kg). The MR images were matched with corresponding histomorphological findings. The signal intensity and contrast ratio of infarcted and normal hepatic lobes were quantified and compared between the two agents during the postcontrast course.

RESULTS

Before contrast, the infarcted lobe was indiscernible from normal liver on T1-weighted MRI. Shortly after injection of both MP-2269 and gadophrin-2, a negative contrast occurred between infarcted and normal liver because of a strong liver signal intensity enhancement and an inferior uptake in the necrotic liver. On delayed phase (>60 minutes), a necrosis-specific contrast enhancement (contrast ratio 1.6) developed with gadophrin-2 but not with MP-2269. The MR images matched well with corresponding histomorphological findings.

CONCLUSIONS

Although both MP-2269 and gadophrin-2 feature an albumin-binding capacity, only gadophrin-2 displayed a persistent necrosis-specific contrast enhancement in the rat model of reperfused liver infarction. Therefore, the role of albumin binding in the mechanisms of NACAs should be reevaluated.

[Correction for the spectral interferences of rare-earth matrix to the determination of calcium by spectral fitting matrix projection-Kalman filter method]

The spectral interferences of trace elements from high purity rare earth will seriously affect the analytical accuracy in the ICP-AES analysis. In this work, spectral fitting matrix projection-Kalman filter method was developed and applied to correction of spectral interferences produced by rare earth matrix peaks with simple shapes in determination of calcium, and it was applied to correct spectral interferences caused by terbium oxide and dysprosium oxide respectively, and satisfactory results were obtained.

Some nutritional and functional properties of defatted wheat germ protein

Defatted wheat germ protein (DWGP) was isolated by alkaline extraction at pH 9.5 and subsequent isoelectric precipitation at pH 4.0, and its nutritional and functional properties were studied. The results showed that the amino acid content of defatted wheat germ was as high as 26.793 g/100 g, and the contents of eight essential amino acids were all relatively high. The isoelectric point of DWGP was 4.0. When pH >6.0, the DWGP had high solubility with a nitrogen solubility index of 70%. The emulsifying activity and emulsifying stability of DWGP were similar to those of bovine serum albumin and a little higher than those of casein. DWGP had good foaming capacity, but its foaming stability (FS) was not very good. However, the FS of DWGP can be improved through physical, chemical, or enzymatic methods. Moreover, DWGP had excellent water retention (WR); especially at pH 8.0 and a temperature of 70 degrees C, the WR of DWGP was the highest at 229.4%. DWGP offers is a potential source of functional protein isolate for possible food applications.

A novel "cooled-wet" electrode for radiofrequency ablation

In the light of growing demands for improved applicability of radiofrequency ablation (RFA), recently we have developed a novel "cooled-wet" electrode by taking the advantages of both internally cooled and saline-enhanced electrodes. The efficacy of the electrode was evaluated in both ex vivo and in vivo liver RFA under both low and high power output levels. The ablation volume created with the "cooled-wet" electrode appeared to be much larger than that reported up to now with the use of other monopolar electrodes. The mechanisms on how this device optimizes the RF energy delivery are also discussed.

Mechanisms of apoptosis in rat cerebellar granule cells induced by hydroxyl radicals and the effects of EGb761 and its constituents

In this study investigation is made on whether oxidative stress produced by treatment with hydroxyl radicals can induce apoptosis in rat cerebellar granule cells. The protective effects of Ginkgo biloba extract (EGb761) and its active constituents against apoptosis are also examined. The results show that hydroxyl radicals generated by the Fenton reaction induced apoptosis in cerebellar granule cells, which was associated with the decrease in the Bcl-2 mRNA level and the increase in the protein levels of the transcription factors Fos and Jun. Moreover, hydroxyl radicals induced time-dependent lipid peroxidation in cells and caused the changes in the sulfhydryl group binding sites on the membrane proteins. Hydroxyl radicals may induce apoptosis via different signaling pathways. EGb761 attenuated these changes and its different constituents showed different effects. The total flavonoid component of EGb761 and a mixture of flavonoids and terpenes protected cerebellar granule cells from oxidative damage and apoptosis induced by hydroxyl radicals. Total terpenes of EGb761 did not protect against apoptosis. Flavonoids and terpenes did not show a synergistic effect in this regard.

A comparative study on validation of a novel cooled-wet electrode for radiofrequency liver ablation

RATIONALE AND OBJECTIVES

A cooled-wet electrode has been developed for radiofrequency ablation (RFA) that allows simultaneous internal-cooling perfusion ("cooled") and interstitial hypertonic saline infusion ("wet"). The present comparative study was conducted to validate this new device for the increased coagulation volume in RFA.

METHODS

Under low-power (50 W, groups A through F) and high-power (90 W, groups A' through F') control modes, 240 RFA lesions were created on excised beef liver to compare the cooled-wet electrode with other monopolar electrodes. The experimental regimens were as follows: groups A and A', conventional RF electrode; groups B and B', cooled electrode; groups C and C', wet electrode; groups D and D', cooled-wet electrode; groups E and E', cooled-wet electrode but suspended wet function; and groups F and F', cooled-wet electrode but suspended cooled function. The ablation efficacy was evaluated by comparing the lesion sizes as well as parameters of impedance, power output, current, and tip temperature.

RESULTS

With lower impedance and tip temperature but higher power output, the lesion size in groups D (4.90 +/- 0.60 cm) and D' (6.6 +./- 0.99 cm) was significantly larger than that in other groups.

CONCLUSIONS

The use of the cooled-wet electrode could efficiently increase the lesion size for liver ablation.

Regulation of protein kinase D by multisite phosphorylation. Identification of phosphorylation sites by mass spectrometry and characterization by site-directed mutagenesis

Activation of the serine/threonine kinase, protein kinase D (PKD/PKC mu) via a phorbol ester/PKC-dependent pathway involves phosphorylation events. The present study identifies five in vivo phosphorylation sites by mass spectrometry, and the role of four of them was investigated by site-directed mutagenesis. Four sites are autophosphorylation sites, the first of which (Ser(916)) is located in the C terminus; its phosphorylation modifies the conformation of the kinase and influences duration of kinase activation but is not required for phorbol ester-mediated activation of PKD. The second autophosphorylation site (Ser(203)) lies in that region of the regulatory domain, which in PKC mu interacts with 14-3-3tau. The last two autophosphorylation sites (Ser(744) and Ser(748)) are located in the activation loop but are only phosphorylated in the isolated PKD-catalytic domain and not in the full-length PKD; they may affect enzyme catalysis but are not involved in the activation of wild-type PKD by phorbol ester. We also present evidence for proteolytic activation of PKD. The fifth site (Ser(255)) is transphosphorylated downstream of a PKC-dependent pathway after in vivo stimulation with phorbol ester. In vivo phorbol ester stimulation of an S255E mutant no longer requires PKC-mediated events. In conclusion, our results show that PKD is a multisite phosphorylated enzyme and suggest that its phosphorylation may be an intricate process that regulates its biological functions in very distinct ways.

Specificity and prevalence of natural bovine anti-alpha galactosyl (Galalpha1-6Glc or Galalpha1-6Gal) antibodies

Immunity against the carbohydrate components of microorganisms mediated by antibodies is an important part of host defenses. Humans and closely related primates, but not other mammals, possess natural anti-Galalpha1-3Gal antibodies which also, although less avidly, react with melibiose (Galalpha1-6Glc). Using an enzyme-linked immunosorbent assay (ELISA) with melibiose-bovine serum albumin as an antigen, we analyzed bovine anti-alpha galactosyl antibodies with respect to specificity and distribution in individual animals. Inhibition assays showed that melibiose was the strongest inhibitor, followed equally by stachyose (Galalpha1-6Galalpha1-6Glcbeta1-2Fru) and raffinose (Galalpha1-6Glcbeta1-2Fru) and then by Galbeta1-6Gal, Gal, and Galalpha1-2Gal. Others, including Galalpha1-3Gal and Galalpha1-4Gal, only exhibited minor inhibition. Thus, these bovine anti-alpha galactosyl antibodies appeared to preferentially react with Galalpha1-6Glc or Galalpha1-6Gal. The distinction of this specificity from that (Galalpha1-3Gal) of human antibodies was further demonstrated by the poor reaction of bovine serum to the Galalpha1-3Gal antigen in comparison to human serum. All 27 healthy bovine serum samples of the three age groups (newborn, calf, and adult) tested contained such antibodies with titers increasing with age. The antibodies purified by affinity chromatography using a melibiose-agarose column were mainly of the immunoglobulin G (IgG) isotype with a concentration of >23 microg/ml in most samples. IgG1 was found to be the primary antimelibiose IgG isotype in all age groups by isotype-specific ELISA, but a significant increase in IgG2, an isotype more related to innate immunity, was observed in calves and adults, compared to newborns. The purified antibodies reacted with the type II bovine strain of Streptococcus agalactiae, a common pathogen of bovine mastitis. Thus, these anti-Galalpha1-6Glc or Galalpha1-6Gal antibodies in cattle might be involved in defense against microbes bearing this or the related epitopes.