ATP synthases in the year 2000: evolving views about the structures of these remarkable enzyme complexes

This introductory article briefly summarizes how our views about the structural features of ATP synthases (F0F1) have evolved over the past 30 years and also reviews some of our current views in the year 2000 about the structures of these remarkably unique enzyme complexes. Suffice it to say that as we approach the end of the first year of this new millinium, we can be conservatively confident that we have a reasonably good grasp of the overall "low-resolution" structural features of ATP synthases. Electron microscopy techniques, combined with the tools of biochemistry, molecular biology, and immunology, have played the leading role here by identifying the headpiece, basepiece, central stalk, side stalk, cap, and in the mitochondrial enzyme, the collar around the central stalk. We can be reasonably confident also that we have a fairly good grasp of much of the "high-resolution" structural features of both the F1 moiety comprised of fives subunit types (alpha, beta, gamma, delta, and epsilon) and parts of the F0 moiety comprised of either three (E. coli) or at least ten (mitochondria) subunit types. This information acquired in several different laboratories, either by X-ray crystallography or NMR spectroscopy, includes details about the active site and subunit relationships. Moreover, it is consistent with recently reported data that the F1 moiety may be an ATP driven motor, which, during ATP synthesis, is driven in reverse by the electrochemical proton gradient generated by the electron transport chain. The real structural challenges of the future are to acquire at high resolution "complete" ATP synthase complexes representative of different stages of the catalytic cycle during ATP synthesis and representative also of key regulatory states.

Correlation of automated visual field parameters and peripapillary nerve fiber layer thickness as measured by scanning laser polarimetry

PURPOSE

To correlate Humphrey visual field mean sensitivity and peripapillary nerve fiber layer thickness as measured by scanning laser polarimetry.

METHODS

The authors studied 54 eyes of 34 patients who visited a university-based glaucoma clinic and had undergone scanning laser polarimetry and Humphrey perimetry within 6 months. The study population included normal patients and those with glaucoma, ocular hypertension, and glaucoma suspect. The authors correlated visual field sensitivity with peripapillary nerve fiber thickness, and visual field mean deviation with the average deviation from the normal nerve fiber layer thickness. They also correlated the visual field mean deviation with all available GDx Nerve Fiber Analyzer parameters.

RESULTS

The visual field mean sensitivity and deviation showed a bilinear correlation to peripapillary nerve fiber layer thickness. The visual field mean sensitivity changed little when the nerve fiber layer thickness was greater than 70 microm. The nerve fiber layer thickness below this level was associated with a rapid decrease in the visual field sensitivity. Similarly, the visual field mean deviation was close to 0 dB when the nerve fiber layer was within -10 microm of the normal value; below this thickness, the mean deviation became substantially more negative. There was a large individual variability around the bilinear fit. Of the scanning laser polarimetry parameters, a calculated index, referred to as the number, had the highest correlation with the Humphrey mean deviation.

CONCLUSION

The bilinear correlation and its variability between the scanning laser polarimetry and visual field parameters make it difficult to predict the result of one from the other. In general, the correlation between the two is better when there is a significant visual field defect than when the visual field is close to normal.

Binding of beta-carbolines and related agents at serotonin (5-HT(2) and 5-HT(1A)), dopamine (D(2)) and benzodiazepine receptors

A large series of beta-carbolines was examined for their ability to bind at [3H]agonist-labeled 5-HT(2A) serotonin receptors. Selected beta-carbolines were also examined at 5-HT(2C) serotonin receptors, 5-HT(1A) serotonin receptors, dopamine D(2) receptors, and benzodiazepine receptors. Indolealkylamines and phenylisopropylamines were also evaluated in some of these binding assays. The beta-carbolines were found to bind with modest affinity at 5-HT(2A) receptors, and affinity was highly dependent upon the presence of ring substituents and ring saturation. The beta-carbolines displayed little to no affinity for 5-HT(1A) serotonin receptors, dopamine D(2) receptors and, with the exception of beta-CCM, for benzodiazepine receptors. Examples of beta-carbolines, indolealkylamines (i.e. N,N-dimethyltryptamine analogs), and phenylisopropylamines have been previously shown to produce common stimulus effects in animals trained to discriminate the phenylisopropylamine hallucinogen DOM (i.e. 1-(2, 5-dimethoxy-4-methylphenyl)-2-aminopropane) from vehicle. Although the only common receptor population that might account for this action is 5-HT(2A), on the basis of a lack of enhanced affinity for agonist-labeled 5-HT(2A) receptors, as well as on their lack of agonist action in the PI hydrolysis assay, it is difficult to conclude that the beta-carbolines behave in a manner consistent with that of other classical hallucinogens.

alpha -galactosylceramide-activated Valpha 14 natural killer T cells mediate protection against murine malaria

Natural killer T (NKT) cells are a unique population of lymphocytes that coexpress a semiinvariant T cell and natural killer cell receptors, which are particularly abundant in the liver. To investigate the possible effect of these cells on the development of the liver stages of malaria parasites, a glycolipid, alpha-galactosylceramide (alpha-GalCer), known to selectively activate Valpha14 NKT cells in the context of CD1d molecules, was administered to sporozoite-inoculated mice. The administration of alpha-GalCer resulted in rapid, strong antimalaria activity, inhibiting the development of the intrahepatocytic stages of the rodent malaria parasites Plasmodium yoelii and Plasmodium berghei. The antimalaria activity mediated by alpha-GalCer is stage-specific, since the course of blood-stage-induced infection was not inhibited by administration of this glycolipid. Furthermore, it was determined that IFN-gamma is essential for the antimalaria activity mediated by the glycolipid. Taken together, our results provide the clear evidence that NKT cells can mediate protection against an intracellular microbial infection.

Radical cyclization of beta-aminoacrylates: synthesis of (-)-indolizidine 223AB

[reaction: see text] (-)-Indolizidine 223AB was synthesized via radical cyclization of the beta-aminoacrylate derivative of a trans-2,5-disubstituted pyrrolidine. The trans-2,5-disubstituted pyrrolidine substrate was prepared by radical cyclization of a Ses-protected beta-aminoacrylate.

Specificity and efficiency of Cre-mediated recombination in Emx1-Cre knock-in mice

Emx1 is a mouse homologue of the Drosophila homeobox gene empty spiracles and its expression is restricted to the neurons in the developing and adult cerebral cortex and hippocampus. We reported previously the creation of a line of transgenic mice in which the cre gene was placed directly downstream of the putative Emx1 promoter using ES cell technology. We showed that Cre protein was present in the cerebral cortex of the transgenic mice and was able to mediate loxP-specific recombination in vitro. In the present study, the specificity and efficiency of the cre-mediated recombination were determined using three independent lines of reporter mice and a combination of histochemical staining, neuronal culture, and Southern detection of the genomic DNA. Our results showed that the recombination was highly efficient in all three lines of reporter mice tested and confirmed that the deletion was restricted to the neurons in the cerebral cortex and hippocampus. Furthermore, we have determined that the recombination efficiency in the cerebral cortex was 91%. Our results suggest that Emx1 is not expressed in every neuron in the developing and adult cerebral cortex. This line of cre mice should contribute to the studies of cortical development and plasticity.

Effects of Huangdan capsule on plasma cGMP and ANP in rats with chronic renal failure

The model of chronic renal failure (CRF) was made in 5/6 nephrectomized rats and Huangdan capsule was used to treat these rats. The levels of cyclic guanosine monophosphate (cGMP) and atrial natriuretic peptide (ANP) in plasma were examined. The results showed that Huangdan capsule could postpone the increase in the levels of cGMP and ANP, suggesting that by regulating the water and sodium metabolism, Huangdan capsule could ameliorate the glomerular filtration rate, and that Huangdan capsule could lower the levels of cGMP and ANP in plasma via body regulation.

[Expression of multidrug resistance gene and its reversion by cyclosporine in non-small cell lung cancer]

BACKGROUND

To investigate relation between the multidrug resistance gene (MDR1) expression and chemotherapeutic response for non-small cell lung cancer (NSCLC) and to evaluate the effect of cyclosporine (CsA) on reversion of MDR1.

METHODS

Cancer tissue specimens and peripheral blood samples were collected from 46 patients with NSCLC. MDR1 was amplified in total RNA extracted from cancer cell specimens and peripheral blood lymphocyte (PBL) by RT-PCR assay. According to the result of detection , some MDR1-positive patients were treated with CsA and anticancer drugs (reverse group) , other MDR1-positive patients (positive control group) and MDR1-negative patients (negative control group) were treated with anticancer drugs alone.

RESULTS

The MDR1 positive rate of cancer cells was 65. 2 %(30/ 46) , and of PBL was 58. 7 %(27/ 46) ; twenty-four cases were MDR1-positive both in cancer cells and PBL. The positive rate of patients with recurrence was 81. 3 %(26/ 32) ; of untreated patients was 28. 6 %(4/ 14) ; of patients with multi-cycle chemotherapy was 85. 7 %(24/ 28) ; of patients with non-chemotherapy was 33. 3 %(6/ 18) . The differences were significant ( P < 0. 01) . The response rate was 46. 7 %(7/ 15) in reverse group and 20 %(3/ 15) in positive control group and 37. 5 %(6/ 16) in negative control group. There were no significant differences in the toxicities and immunity changes except for hematological toxicity and impaired liver function between reverse group and other groups.

CONCLUSIONS

RT-PCR examination of MDR1 expression is useful for predicting response to chemotherapy and prognosis in NSCLC patients. MDR1-positive is associated with poor prognosis. The reverse effect of CsA for expression of MDR1 requires further clinical study.

Localization of C-terminal domains required for the maximal activity or for determination of substrate preference of maize branching enzymes

Previous analysis of a chimeric enzyme mBEII-IBspHI, in which the C-terminal 229 amino acids of maize endosperm branching enzyme isoform II (mBEII) are replaced by the corresponding 284 amino acids of isoform I (mBEI), suggested that the carboxyl terminus of maize branching enzymes may be involved in catalytic efficiency and substrate preference. In the present study, additional hybrids of mBEI and mBEII were generated and expressed in Escherichia coli BL21 (DE3) to dissect the structure/function relationships of the C-terminal regions of maize branching enzymes. A truncated form of purified mBEII-IBspHI, which lacks the C-terminal 58 amino acids, retained similar levels of V(max) in branching activity, K(m) for reduced amylose AS 320, and substrate preference for amylose than amylopectin when compared to mBEII-IBspHI. This indicates that the C-terminal extension derived from mBEI is not required for either catalysis or substrate preference. However, deletion of an additional 87 amino acids from the carboxyl terminus resulted in complete loss of activity. Replacement of the deleted C-terminal additional 87 amino acids with the corresponding 79 amino acids from mBEII restored 25% of the mBEII-IBspHI branching activity without altering substrate preference. It thus appears that a C-terminal region encompassing Leu649-Asp735 of mBEII-IBspHI is required for maximum catalytic efficiency. Another C-terminal region, residues Gln510-Asp648, of mBEII-IBspHI (Gln476-Asp614 of mBEI) may be involved in substrate-preference determination.

A nanoplotter with both parallel and serial writing capabilities

The development of an eight-pen nanoplotter capable of doing parallel dip-pen nanolithography (DPN) is reported. Because line width and patterning speed in DPN are independent of contact force, only one of the tips in the parallel writing mode (the "imaging" tip) has a feedback system to monitor tip position and to write the pattern; all other tips reproduce what occurs at the imaging tip in a passive fashion. Proof-of-concept experiments that demonstrate eight-pen parallel writing, ink and rinsing wells, and "molecular corralling" via a nanoplotter-generated structure are reported.

Treadmill exercise training blunts suppression of splenic natural killer cell cytolysis after footshock

This study extended to treadmill exercise training our prior report (Dishman RK, Warren JM, Youngstedt SD, Yoo H, Bunnell BN, Mougey EH, Meyerhoff JL, Jaso-Friedmann L, and Evans DL. J Appl Physiol 78: 1547-1554, 1995) that activity wheel running abolished the suppression of footshock-induced natural killer (NK) cell cytolysis. Twenty-four male Fischer 344 rats were assigned to one of three groups (n = 8, all groups): 1) a home-cage control group, 2) a sedentary treatment group, or 3) a treadmill-running group (0 degrees incline, 25 m/min, 35 min/day, 6 days/wk). After 6 wk, the treadmill and sedentary groups received 2 days of footshock. Splenic NK cytotoxicity was determined by standard 4-h (51)Cr release assay. Percentages of lymphocytes were determined by flow cytometry. Plasma levels of ACTH, corticosterone, and prolactin concentration were measured by radioimmunoassay. After footshock, percentage of lysis relative to home-cage controls was 40% and 80% for sedentary and treadmill-trained animals, respectively (P < 0.05). Our results indicate that the protective effect of chronic exercise on innate cellular immunity in the Fischer 344 male rat is not restricted to activity wheel running, nor is it explained by elevations in basal NK activity, increased percentages of splenic NK and cytotoxic T cells, or increased plasma levels of ACTH, corticosterone, and prolactin.

[Retrospective analysis of 266 cases of pregnancy complicated by heart disease]

OBJECTIVE

To investigate the influence of cardiac function of pregnant women on outcome of their pregnancies.

METHODS

Clinical data of 266 cases of pregnant women with heart diseases from January, 1993 to March, 1999 were analyzed retrospectively.

RESULTS

(1) The highest incidence of cardiac disease with grade I to II of heart function was due to myocarditis, sequelae of myocarditis and abnormal cardiac rhythm (179 cases, 67.29%). The incidence of congenital heart disease is on the second (41 cases, 15.41%) which is higher than that of rheumatic heart disease (28 cases, 10.91%). (2) Grade III and IV cardiac function was mainly related to congenital and rheumatic heart diseases during pregnancy. The rate of grade I/II heart function in pregnant women after heart operations was 95.45%. (3) The incidence of premature delivery, low weight of newborns and perinatal mortality of mother were higher in women with grade III and IV heart function than in those with grade I and II heart function.

CONCLUSIONS

The incidence of myocarditis and sequelae of myocarditis is increasing. Pregnancies complicated with congenital and rheumatic heart diseases are still major causes of perinatal morbidity and mortality of mother and baby. Heart operation can obviously improve the heart function. More effective managements should be adopted.

Relative contribution of NK and NKT cells to the anti-metastatic activities of IL-12

Conventional T cells, NK cells and NKT cells have been implicated in the anti-tumor activities induced by IL-12. Here we show that IL-12-induced immune responses are partially impaired in T and NKT cell-deficient RAG-2(-/-) mice, and in NKT cell-deficient CD1(-/-) mice. In response to a small dose (<1000 U) of IL-12, RAG-2(-/-) and CD1(-/-) mice demonstrated reduced cytotoxicity, serum IFN-gamma elevation and anti-metastatic activities; in contrast, in response to a high dose (>2000 U) of IL-12, the IL-12-induced immune responses of RAG-2(-/-) and CD1(-/-) mice were indistinguishable from wild-type mice. The defective responses to low-dose IL-12 of RAG-2(-/-) mice were corrected by adoptive transfer of NKT cells but not NK cells. These findings indicate that both NK and NKT cells contribute to the anti-metastatic responses induced by IL-12, and that NKT cells are mostly responsible for the low-dose activities of this cytokine.

Relative contributions of distinct MHC class I-dependent cell populations in protection to tuberculosis infection in mice

A necessary role for cytotoxic T lymphocytes in protection against Mycobacterium tuberculosis (MTB) has been suggested by studies of the beta2-microglobulin-deficient mouse, which is unable to present antigens through MHC class I and class I-like molecules and invariably succumbs early after infection. To identify the relative contributions of distinct putative MHC class I-dependent cell populations in protection against tuberculosis, we compared a variety of gene-disrupted mouse strains for susceptibility to MTB infection. Among the strains tested, the most susceptible mice, as measured by survival time and bacterial loads, were the beta2-microglobulin(-/-), followed by transporter associated with antigen processing deficient (TAP1(-/-)), CD8alpha(-/-), perforin(-/-), and CD1d(-/-) mice. These findings indicated that (i) CD8(+) T cells contribute to protection against MTB, and their protective activity is only partially dependent on perforin; (ii) beta2-microglobulin-dependent T cell populations distinct from CD8(+) T cells also contribute to anti-MTB immunity; and (iii) protective immune mechanisms are predominantly TAP-dependent, although TAP-independent mechanisms also contribute to protection. Because CD1d-deficient animals were fully resistant to MTB, other TAP-independent mechanisms must contribute to protection. We suggest here that both classical and nonclassical MHC class I-restricted T cells, distinct from CD1d-restricted cells, may be involved in protective immune responses against tuberculosis.

Cerebral palsy and multiple births in China

BACKGROUND

A population-based study on prevalence of cerebral palsy in multiple births has not been carried out in China. The purpose of this paper was to determine the prevalence of cerebral palsy in multiple births and to explore the influence of multiple pregnancy on cerebral palsy after controlling for birthweight.

METHODS

A cross-sectional study of cerebral palsy was carried out among 388,192 children aged <7 years in seven cities of Jiangsu province in China. Information about birthweight and plurality was obtained from routine health care records. Pediatricians at city level diagnosed all cases. All the doctors involved had taken part in a training programme held by Beijing Medical University. Stratified analysis by birthweight and its standard normal deviate was employed to compare the prevalence of cerebral palsy in multiples and singletons.

RESULTS

The prevalence of cerebral palsy for children aged <7 years in multiples was 9.7 per 1000 children (95% confidence interval [CI]: 6.5-14.0), which was 6.5 times that in singletons (95% CI: 4.4-9.3). The overall neonatal mortality rate was 60.9 per 1000 liveborn multiples, being highest (944.4 per 1000) in the 500-999 g birthweight groups. Most liveborn multiples weighing <1500 g at birth probably died from diseases related to very low birthweight prior to this study. The prevalence of cerebral palsy in multiple births was likely to be higher than that reported in developed countries for children weighing 1500-2499 g even though our data were from a cross-sectional study. When stratified by birthweight, the prevalence of cerebral palsy in multiples weighing <2500 g had tended to be lower than that of singletons in the same birthweight group. In contrast, in normal birthweight categories multiple births had a higher prevalence of cerebral palsy than singletons. When stratified by birthweight normal deviate, the prevalence of cerebral palsy in multiple births was uniformly higher than that in singletons in all birthweight strata and the prevalence of cerebral palsy among multiples appeared to be augmented as birthweight increased.

CONCLUSION

The prevalence of cerebral palsy in multiples, 9.7 per 1000 children, is 6.5 times that in singletons. Survival of low birthweight infants is lower in China than in developed countries and survival quality of Chinese children weighing 1500-2499 g needs to be further improved. In terms of birthweight multiples and singletons may be heterogeneous. It might be difficult to directly use actual birthweight specific prevalence to compare the prevalence of cerebral palsy in multiples and singletons. Birthweight normal deviate specific prevalence of cerebral palsy suggests that multiple pregnancy is an independent risk factor for cerebral palsy in all birthweight groups. Multiples are in adverse circumstances very early in gestation and as the foetus matures the risk of cerebral palsy increases.

Physicochemical aspects of the movement of the rieske iron sulfur protein during quinol oxidation by the bc(1) complex from mitochondria and photosynthetic bacteria

Crystallographic structures for the mitochondrial ubihydroquinone:cytochrome c oxidoreductase (bc(1) complex) from different sources, and with different inhibitors in cocrystals, have revealed that the extrinsic domain of the iron sulfur subunit is not fixed [Zhang, Z., Huang, L., Shulmeister, V. M., Chi, Y.-I., Kim, K. K., Hung, L.-W., Crofts, A. R., Berry, E. A., and Kim, S.-H. (1998) Nature (London), 392, 677-684], but moves between reaction domains on cytochrome c(1) and cytochrome b subunits. We have suggested that the movement is necessary for quinol oxidation at the Q(o) site of the complex. In this paper, we show that the electron-transfer reactions of the high-potential chain of the complex, including oxidation of the iron sulfur protein by cytochrome c(1) and the reactions by which oxidizing equivalents become available at the Q(o) site, are rapid compared to the rate-determining step. Activation energies of partial reactions that contribute to movement of the iron sulfur protein have been measured and shown to be lower than the high activation barrier associated with quinol oxidation. We conclude that the movement is not the source of the activation barrier. We estimate the occupancies of different positions for the iron sulfur protein from the crystallographic electron densities and discuss the parameters determining the binding of the iron sulfur protein in different configurations. The low activation barrier is consistent with a movement between these locations through a constrained diffusion. Apart from ligation in enzyme-substrate or inhibitor complexes, the binding forces in the native structure are likely to be < = RT, suggesting that the mobile head can explore the reaction interfaces through stochastic processes within the time scale indicated by kinetic measurements.

Is ethanol an important antioxidant in alcoholic beverages associated with risk reduction of cataract and atherosclerosis?

It has been reported in the epidemiological literature that cataract, stroke, and atherosclerosis risk is reduced by 50% in people consuming one alcoholic drink per day. Peroxide has been implicated as a causative agent in cataractogenesis, and LDL oxidation appears to play a role in atherosclerosis. The antioxidant activity of alcohol was measured by: (i) use of a luminescent assay developed in our laboratory, confirmed as appropriate; (ii) electron spin resonance (ESR) spin-trapping; and (iii) copper-catalysed oxidation of LDL and VLDL from hamsters fed 6% ethanol in their drinking water. Ethanol reduced the luminescent counts/min from peroxide and superoxide. It significantly reduced the spin-trapped signal of hydroxyl radical, but not the superoxide signal. Other alcohols also showed large reductions in counts from hydrogen peroxide. Plasma from hamsters fed 6% ethanol had lower lipid peroxides and the oxidizability of LDL and VLDL was significantly reduced compared to controls. These data provide a possible explanation for the effect of beverages containing ethanol in the reduction of cataract and atherosclerosis risk observed in human population studies.

The energy landscape for ubihydroquinone oxidation at the Q(o) site of the bc(1) complex in Rhodobacter sphaeroides

Activation energies for partial reactions involved in oxidation of quinol by the bc(1) complex were independent of pH in the range 5. 5-8.9. Formation of enzyme-substrate complex required two substrates, ubihydroquinone binding from the lipid phase and the extrinsic domain of the iron-sulfur protein. The activation energy for ubihydroquinone oxidation was independent of the concentration of either substrate, showing that the activated step was in a reaction after formation of the enzyme-substrate complex. At all pH values, the partial reaction with the limiting rate and the highest activation energy was oxidation of bound ubihydroquinone. The pH dependence of the rate of ubihydroquinone oxidation reflected the pK on the oxidized iron-sulfur protein and requirement for the deprotonated form in formation of the enzyme-substrate complex. We discuss different mechanisms to explain the properties of the bifurcated reaction, and we preclude models in which the high activation barrier is in the second electron transfer or is caused by deprotonation of QH(2). Separation to products after the first electron transfer and movement of semiquinone formed in the Q(o) site would allow rapid electron transfer to heme b(L). This would also insulate the semiquinone from oxidation by the iron-sulfur protein, explaining the efficiency of bifurcation.

Differential expression of nitric oxide synthase in human stomach cancer

The level of expression and cellular localization of isoenzymes of nitric oxide synthase (NOS) was detected in human stomach tumor tissues. Tumor tissues showed 70% higher activity of NOS than that of normal tissues (P < 0.01). Poorly differentiated adenocarcinoma tend to have higher activity (P < 0.05) than well differentiated and moderately differentiated tumor tissues. Aminoguanidine (AG), 2-amino-5,6-dihydro-6-methyl-4H-1,3-thiazine (AMT), NG-monomethyl-L-arginine (L-NMMA), and Nomega-nitro-L-arginine (L-NNA) inhibited NOS activity in tumor tissues by 18, 14, 11 and 13%, respectively. The TNF-alpha mRNA expression was correlated with the inducible NOS (iNOS) level, which was high in adenocarcinomas and low in normal tissues. Tumor tissues showed higher expression of iNOS in gland epithelial cells but the level of eNOS was significantly decreased with an exception of concentrated localization in the proliferating capillary endothelium. These results revealed that isoforms of NOS might contribute differentially to growth and progression of human stomach tumor.

Hydrogen peroxide activates p70(S6k) signaling pathway

We investigated a possible role of reactive oxygen species (ROS) in p70(S6k) activation, which plays an important role in the progression of cells from G(0)/G(1) to S phase of the cell cycle by translational up-regulation of a family of mRNA transcripts that encode for components of the protein synthetic machinery. Treatment of mouse epidermal cell JB6 with H(2)O(2) generated extracellularly by glucose/glucose oxidase led to the activation of p70(S6k) and p90(Rsk) and to phosphorylation of p42(MAPK)/p44(MAPK). The activation of p70(S6k) and p90(Rsk) was dose-dependent and transient, maximal activities being in extracts treated for 15 and 30 min, respectively. Further characterization of ROS-induced activation of p70(S6k) using specific inhibitors for p70(S6k) signaling pathway, rapamycin, and wortmannin revealed that ROS acted upstream of the rapamycin-sensitive component FRAP/RAFT and wortmannin-sensitive component phosphatidylinositol 3-kinase, because both inhibitors caused the inhibition of ROS-induced p70(S6k) activity. In addition, Ca(2+) chelation also inhibited ROS-induced activation of p70(S6k), indicating that Ca(2+) is a mediator of p70(S6k) activation by ROS. However, down-regulation of 12-O-tetradecanoylphorbol-13-acetate (TPA)-responsive protein kinase C (PKC) by chronic pretreatment with TPA or a specific PKC inhibitor Ro-31-8220 did not block the activation of p70(S6k) by ROS, indicating that the activation of TPA-responsive PKC was not required for stimulation of p70(S6k) activity by H(2)O(2) in JB6 cells. Exposure of JB6 cells to platelet-derived growth factor or epidermal growth factor led to a rapid increase in H(2)O(2), phosphorylation, and activation of p70(S6k), which were antagonized by the pretreatment of catalase. Taken together, the results suggest that ROS act as a messenger in growth factor-induced p70(S6k) signaling pathway.

Generating correlation matrices with model error for simulation studies in factor analysis: a combination of the Tucker-Koopman-Linn model and Wijsman's algorithm

Most simulation studies in factor analysis follow a process of constructing population correlation matrices from the common-factor model and generating sample correlation matrices from the population matrices. In the common-factor model, the population correlation matrix is perfectly fit by the model's containing common and unique factors. However, since no mathematical model accounts exactly for the real-world phenomena that it is intended to represent, the Tucker-Koopman-Linn model (1969) is more realistic for generating correlation matrices than the conventional common-factor model because the former incorporates model error. In this paper, a procedure for generating population and sample correlation matrices with model error by combining the Tucker-Koopman-Linn model and Wijsman's algorithm (1959) is presented. The SAS/IML program for generating correlation matrices is described, and an example is also provided.

Neoadjuvant chemotherapy and radiation therapy compared with radiation therapy alone in advanced nasopharyngeal carcinoma

PURPOSE

To analyze the impact of neoadjuvant chemotherapy on the treatment of locoregionally advanced nasopharyngeal carcinoma and to assess the outcomes of patients receiving such treatment.

METHODS AND MATERIALS

We analyzed 137 previously untreated and histologically confirmed advanced stage nasopharyngeal carcinoma patients treated with either radiation therapy only or combined radiation therapy and chemotherapy at the Seoul National University Hospital between 1984 and 1996. The stage distribution was as follows: AJCC Stage III-21, Stage IV-61 in the radiation therapy group (RT group); AJCC Stage III-1, Stage IV-54 in neoadjuvant chemotherapy and radiation therapy group (CT/RT group). The median follow-up for surviving patients was 48 months.

RESULTS

The 5-year overall survival (OS) rates were 71% for the CT/RT group and 59% for the RT group (p = 0.04). The 5-year actuarial disease-free survival (DFS) rates were 63% for the CT/RT group and 52% for the RT group (p = 0.04). Distant metastasis (DM) incidence was significantly lower in the CT/RT group. The 5-year freedom from distant metastasis rates were 84% for the CT/RT group and 66% for the RT group (p = 0.01). The incidence of locoregional failures was also lower in the CT/RT group, although this difference did not reach statistical significance (69% vs. 56%, p = 0.09)

CONCLUSION

While not providing conclusive evidence, historical evidence from this institution suggests that neoadjuvant chemotherapy significantly improves both overall and the disease-free survival of patients with advanced stage nasopharyngeal carcinoma.

Multiple ink nanolithography: toward a multiple-Pen nano-plotter

The formation of intricate nanostructures will require the ability to maintain surface registry during several patterning steps. A scanning probe method, dip-pen nanolithography (DPN), can be used to pattern monolayers of different organic molecules down to a 5-nanometer separation. An "overwriting" capability of DPN allows one nanostructure to be generated and the areas surrounding that nanostructure to be filled in with a second type of "ink."

Chemical mechanism of ATP synthase. Magnesium plays a pivotal role in formation of the transition state where ATP is synthesized from ADP and inorganic phosphate

The chemical mechanism by which ATP synthases catalyze the synthesis of ATP remains unknown despite the recent elucidation of the three-dimensional structures of two forms of the F(1) catalytic sector (subunit stoichiometry, alpha(3)beta(3)gammadeltaepsilon). Lacking is critical information about the chemical events taking place at the catalytic site of each beta-subunit in the transition state. In an earlier report (Ko, Y. H., Bianchet, M. A., Amzel, L.M., and Pedersen, P. L. (1997) J. Biol. Chem. 272, 18875-18881), we provided evidence for transition state formation in the presence of Mg(2+), ADP, and orthovanadate (V(i)), a photoreactive phosphate analog with a trigonal bipyramidal geometry resembling that of the gamma-P of ATP in the transition state of enzymes like myosin. In the presence of ultraviolet light and O(2,) the MgADP.V(i)-F(1) complex was cleaved within the P-loop (GGAGVGKT) of a single beta-subunit at alanine 158, implicating this residue as within contact distance of the gamma-P of ATP in the transition state. Here, we report that ADP, although facilitating transition state formation, is not essential. In the presence of Mg(2+) and V(i) alone the catalytic activity of the resultant MgV(i)-F(1) complex is inhibited to nearly the same extent as that observed for the MgADP. V(i)-F(1) complex. Inhibition is not observed with ADP, Mg(2+), or V(i) alone. Significantly, in the presence of ultraviolet light and O(2,) the MgV(i)-F(1) complex is cleaved also within the P-loop of a single beta-subunit at alanine 158 as confirmed by Western blot analyses with two different antibodies, by N-terminal sequence analyses, and by quantification of the amount of unreacted beta-subunits. These novel findings indicate that Mg(2+) plays a pivotal role in transition state formation during ATP synthesis catalyzed by ATP synthases, a role that involves both its preferential coordination with P(i) and the repositioning of the P-loop to bring the nonpolar alanine 158 into the catalytic pocket. A reaction scheme for ATP synthases depicting a role for Mg(2+) in transition state formation is proposed here for the first time.

Analysis of methyl tert.-butyl ether and its degradation products by direct aqueous injection onto gas chromatography with mass spectrometry or flame ionization detection systems

A method was developed to analyze methyl tert.-butyl ether (MTBE) and its degradation products by gas chromatography with mass spectrometry (GC-MS) or flame ionization detection (FID) with direct aqueous injection. The column had dimensions of 30 m x 0.25 mm with film thickness 0.25 microm and a stationary phase of FFAP (nitroterephthalic acid-modified polyethylene glycol). The optimized GC conditions for non-acid components were as follows: carrier gas flow-rate,l mL/min; oven temperature, 35 degrees C for 5.5 min, ramped to 90 degrees C at 25 degrees C/min, then ramped to 200 degrees C at 40 degrees C/min and held at 200 degrees C for 8 min. The conditions for the acid components were: carrier gas flow-rate, 1 mL/min; oven temperature, 110 degrees C for 2 min, ramped to 150 degrees C at 10 degrees C/min, then ramped to 200 degrees C at 40 degrees C/min. The injection port contained a silanized-glass reverse-cup liner filled with Carbofrit. The minimum concentrations for the linear range for the selective ion monitoring mode were 30 to 100 microg/L, depending on the analytes. The minimum detection limit was 1 mg/L for MTBE and tert.-butanol when using FID. More components could be analyzed with the FFAP-type column than with the cyanopropylphenyl-dimethyl polysiloxane-type column.

Cutting edge: activation of NK T cells by CD1d and alpha-galactosylceramide directs conventional T cells to the acquisition of a Th2 phenotype

NK T cells recognize glycolipid Ags such as alpha-galactosylceramide (alpha-GalCer) presented by the MHC class I-like molecule CD1d. In this paper we have studied the in vivo effects of alpha-GalCer on the generation of adaptive immune responses. Treatment of mice with alpha-GalCer resulted in rapid activation of NK T cells and production of the cytokines IL-4 and IFN-gamma. However, after this initial stimulation, NK T cells became polarized for the production of IL-4. Further, as soon as 6 days after alpha-GalCer injection, a marked increase in serum IgE levels was observed. Administration of alpha-GalCer at the time of priming of mice with protein Ag resulted in the generation of Ag-specific Th2 cells and a profound increase in the production of IgE. Collectively, these findings indicate that alpha-GalCer may be useful for modulating immune responses toward a Th2 phenotype during prophylaxis and therapy.

Pathways for proton release during ubihydroquinone oxidation by the bc(1) complex

Quinol oxidation by the bc(1) complex of Rhodobacter sphaeroides occurs from an enzyme-substrate complex formed between quinol bound at the Q(o) site and the iron-sulfur protein (ISP) docked at an interface on cytochrome b. From the structure of the stigmatellin-containing mitochondrial complex, we suggest that hydrogen bonds to the two quinol hydroxyl groups, from Glu-272 of cytochrome b and His-161 of the ISP, help to stabilize the enzyme-substrate complex and aid proton release. Reduction of the oxidized ISP involves H transfer from quinol. Release of the proton occurs when the acceptor chain reoxidizes the reduced ISP, after domain movement to an interface on cytochrome c(1). Effects of mutations to the ISP that change the redox potential and/or the pK on the oxidized form support this mechanism. Structures for the complex in the presence of inhibitors show two different orientations of Glu-272. In stigmatellin-containing crystals, the side chain points into the site, to hydrogen bond with a ring hydroxyl, while His-161 hydrogen bonds to the carbonyl group. In the native structure, or crystals containing myxothiazol or beta-methoxyacrylate-type inhibitors, the Glu-272 side chain is rotated to point out of the site, to the surface of an external aqueous channel. Effects of mutation at this residue suggest that this group is involved in ligation of stigmatellin and quinol, but not quinone, and that the carboxylate function is essential for rapid turnover. H(+) transfer from semiquinone to the carboxylate side chain and rotation to the position found in the myxothiazol structure provide a pathway for release of the second proton.

Identification of a cytoplasmic targeting/retention signal in a retroviral Gag polyprotein

Retroviral capsid assembly can occur by either of two distinct morphogenic processes: in type C viruses, the capsid assembles and buds at the plasma membrane, while in type B and D viruses, the capsid assembles within the cytoplasm and is then transported to the plasma membrane for budding. We have previously reported that a single-amino-acid substitution of a tryptophan for an arginine in the matrix protein (MA) of Mason-Pfizer monkey virus (MPMV) converts its capsid assembly from that of a type D retrovirus to that of the type C viruses (S. S. Rhee and E. Hunter, Cell 63:77-86, 1990). Here we identify a region of 18 amino acids within the MA of MPMV that is responsible for type D-specific morphogenesis. Insertion of these 18 amino acids into the MA of type C Moloney murine leukemia virus causes it to assemble an immature capsid in the cytoplasm. Furthermore, fusion of the MPMV MA to the green fluorescent protein resulted in altered intracellular targeting and a punctate accumulation of the fusion protein in the cytoplasm. These 18 amino acids, which are necessary and sufficient to target retroviral Gag polyproteins to defined sites in the cytoplasm, appear to define a novel mammalian cytoplasmic targeting/retention signal.

[A case-control study on cerebral palsy in children]

OBJECTIVE

To identify the risk factors for cerebral palsy (CP) in children.

METHODS

A population-based 1:2 matched case-control study was conducted during May to June 1997 in southern Jiangsu Province of China.

RESULTS

Risk factors for CP in children could be summarized into four categories, i.e.; (1) fetal growth retardation, preterm delivery and low birth weight; (2) asphyxia at birth, intracranial hemorrhage, ischemic and hypoxic encephalopathy and hyperbilirubinemic encephalopathy; (3) delivery with vaccum suction and traumatic brain injury; and (4) other prenatal factors.

CONCLUSION

The first and second categories of risk factors correlated strongly and reproducibly with CP in children. It is emphasized that antenatal care be enforced to prevent occurrence of risk factors, such as low birth weight, etc., and the newborns with asphyxia be vigorously rescued and put under close supervision. For risk factors in the third category, the key measures should be obstetric practice and health education for the parents. But, little about the knowledge of the risk factors in the fourth category has been understood, which could be associated with those in the first two categories.

IL-7 up-regulates IL-4 production by splenic NK1.1+ and NK1.1- MHC class I-like/CD1-dependent CD4+ T cells

NK T cells are an unusual subset of T lymphocytes. They express NK1. 1 Ag, are CD1 restricted, and highly skewed toward Vbeta8 for their TCR usage. They express the unique potential to produce large amounts of IL-4 and IFN-gamma immediately upon TCR cross-linking. We previously showed in the thymus that the NK T subset requires IL-7 for its functional maturation. In this study, we analyzed whether IL-7 was capable of regulating the production of IL-4 and IFN-gamma by the discrete NK T subset of CD4+ cells in the periphery. Two hours after injection of IL-7 into mice, or after a 4-h exposure to IL-7 in vitro, IL-4 production by CD4+ cells in response to anti-TCR-alphabeta is markedly increased. In contrast, IFN-gamma production remains essentially unchanged. In beta2-microglobulin- and CD1-deficient mice, which lack NK T cells, IL-7 treatment does not reestablish normal levels of IL-4 by CD4+ T cells. Moreover, we observe that in wild-type mice, the memory phenotype (CD62L-CD44+) CD4+ T cells responsible for IL-4 production are not only NK1.1+ cells, but also NK1.1- cells. This NK1.1-IL-4-producing subset shares three important characteristics with NK T cells: 1) Vbeta8 skewing; 2) CD1 restriction as demonstrated by their absence in CD1-deficient mice and relative overexpression in MHC II null mice; 3) sensitivity to IL-7 in terms of IL-4 production. In conclusion, the present study provides evidence that CD4+MHC class I-like-dependent T cell populations include not only NK1.1+ cells, but also NK1.1- cells, and that these two subsets are biased toward IL-4 production by IL-7.

[Application of modified ultrafiltration to cardiac surgery in adults]

Modified Ultrafiltration (MUF) was developed for blood concentration and reduction of postoperative edema in cardiac surgery in children. Its beneficial effects on postoperative hemodynamics have been reported. We applied MUF to cardiac surgery in adults and evaluated its usefulness. Between August, 1995 and April, 1997, MUF was performed in 41 adult patients. MUF was carried out immediately after the cessation of cardiopulmonary bypass. The mean fluid volume removed was 1,135.9 +/- 274.1 ml. The patient's haematocrit significantly increased from 23.2 +/- 2.6% to 26.9 +/- 3.2% (p < 0.0001). The dose of inotropes administered was maintained constant during MUF, and no changes were observed in CVP and the heart rate. However, the systolic blood pressure increased from 99.5 +/- 14.7 to 113.2 +/- 16.2 mmHg (p < 0.0001) and cardiac index from 4.2 +/- 0.9 to 4.9 +/- 1.3 l/min/m2 (p = 0.0006). It was suggested that MUF was an useful technique of haemoconcentration and appeared to have beneficial effects on postoperative hemodynamics in adult cardiac surgery.

The alpha-subunit of human choriogonadotropin interacts with the exodomain of the luteinizing hormone/choriogonadotropin receptor

The LH/CG receptor, a G protein-coupled receptor, consists of two parts, the N-terminal extracellular segment (exodomain) and the membrane-associated C-terminal segment (endodomain). hCG initially binds the exodomain of the receptor and then, the hormone/exodomain complex is thought to make the secondary contact with the endodomain of the receptor and generate a hormone signal. However, little direct evidence is available about which hormone subunits (alpha or beta) interact with which domains of the receptor. To determine whether the alpha-subunit contacts the exodomain of its receptor, hCG containing [125I]alpha and truncated exodomain lacking the endodomain were prepared. They were chemically cross-linked, and the resulting cross-linked complexes were solubilized and electrophoresed. The results indicate that the alpha-subunit of hCG was directly and specifically cross-linked to the exodomain. To verify the cross-linked exodomain by the independent method, the Flag epitope was inserted between the signal sequence and the mature exodomain. hCG containing [125I]alpha was cross-linked to the Flag exodomain, and the resulting cross-linked hCG/Flag exodomain complexes were immunoprecipitated with anti-Flag antibody. The results show that the material cross-linked to hCG containing [125I]alpha is indeed the exodomain. In conclusion, our results show the direct interaction of the alpha-subunit with the exodomain and, therefore, its crucial role in the hormone-receptor interaction in addition to its involvement in signal generation.

Lipid antigen presentation in the immune system: lessons learned from CD1d knockout mice

CD1 molecules represent a distinct lineage of antigen-presenting molecules that are evolutionarily related to the classical major histocompatibility complex (MHC) class I and class II molecules. Unlike the classical MHC products that bind peptides, CD1 molecules have evolved to bind lipids and glycolipids. Murine and human CD1d molecules can present glycolipid antigens such as alpha-galactosylceramide (alpha-GalCer) to CD1d-restricted natural killer (NK) T cells. Using CD1d knockout mice we demonstrated that CD1d expression is required for the development of NK T cells. These animals were also deficient in the rapid production of interleukin-4 and interferon-gamma in response to stimulation by anti-CD3 antibodies. Despite these defects, CD1d knockout animals were able to generate strong T-helper type 1 (TH1) and TH2 responses. Spleen cells from these animals neither proliferated nor produced cytokines in response to stimulation by alpha-GalCer. Repeated injection of alpha-GalCer into wild-type but not CD1d mutant mice was able to clear metastatic tumors. We further showed that alpha-GalCer can inhibit disease in diabetes-prone non-obese diabetic mice. Collectively, these findings with CD1d knockout animals indicate a critical role for CD1d-dependent T cells in various disease conditions, and suggest that alpha-GalCer may be useful for therapeutic intervention in these diseases.

Noncompetitive, Ca(2+)-independent inhibition of pyruvate dehydrogenase phosphatase by fluphenazine

The effects of two different classes of calmodulin antagonists on the catalytic activities of purified pyruvate dehydrogenase (PDH) phosphatase and PDH complex (PDC) were studied. In general, PDH phosphatase was more strongly inhibited than PDC by the calmodulin antagonists with the following potency order: fluphenazine > chlorpromazine > thioridazine > triflupromazine. Promazine and two sulfonamides (W-5 and W-7) did not suppress PDH phosphatase activity at 1 mM concentrations, while about 20% of PDC activity was inhibited by these antagonists. Fluphenazine-mediated inhibition of PDH phosphatase was observed with the purified PDC as well as intact mitochondria. Although Ca2+ stimulates PDH phosphatase activity, the addition of exogenous Ca2+ did not overcome the inhibition by calmodulin antagonists. These results suggest that the suppression of PDH phosphatase activity is dependent upon the structure of the individual calmodulin antagonist and appears to be Ca(2+)-independent. Kinetic analysis showed a noncompetitive inhibition of PDH phosphatase by fluphenazine, indicating that it binds to different site(s) from the catalytic site of the enzyme.

New Polyolefin Elastomers Containing “Reactive” p-Methylstyrene Units: Preparation by Metallocene Catalysts

This paper summarizes the experimental results of three new polyolefin elastomers, i.e., poly(1-octene-co- p-methylstyrene (O-p-MS), poly(ethylene-ter-propylene-ter-p-methylstyrene) (EP-p-MS) and poly(ethylene-ter-1-octene-ter-p-methylstyrene) (EO-p-MS), containing “reactive” p-MS units. Both Ziegler-Natta and metallocene catalysts were used in studying co- and ter-polymerization reactions. In the copolymerization of 1-octene and p-MS, Ziegler-Natta catalyst TiCl3/AlEt3 exhibits higher catalyst reactivity to produce high molecular weight O-p-MS copolymers, containing up to 20 mol % p-MS. However, the copolymers show very broad composition and molecular weight distributions. On the other hand, two EP-p-MS and EO-p-MS terpolymers with narrow molecular weight and composition distributions were prepared by [C5Me4(SiMe2NtBu)]TiCl2 metallocene catalyst with constrained ligand geometry. The sharp glass transition temperature (Tg) with flat baseline in each differential scanning calorimetry (DSC) curve indicates homogeneous terpolymer microstructures. The Tg of EP-p-MS is very sensitive to the terpolymer composition (ethylene/propylene ratio and p-MS content). In the compositions with ideal ethylene/propylene ratio ∼ 55/45, the Tα is almost proportional to the content of p-MS. Only with the concentration of p-MS &lt; 2 mol %, does the EP-p-MS show alow Tg&lt;−45°C. On the other hand, the EO-p-MS system exhibits a low Tg&lt;−50°C in a wide range of copolymer compositions, even ones with relatively high p-MS contents (&lt; 7 mol %).

Peptide dependency of alloreactive CD4+ T cell responses

Alloreactivity, the capacity of a large number of T lymphocytes to react with foreign MHC molecules, represents the cellular basis for the rejection of tissue grafts. Although it was originally assumed that the TCR of alloreactive T cells focus their recognition on the polymorphic residues that differ between the MHC molecules of responder and stimulator cells, studies in the MHC class I system have clearly demonstrated that MHC-bound peptides can influence this interaction. It remains unclear, however, whether peptides play an equally important role for the recognition of MHC class II molecules by alloreactive CD4+ T cells. Another issue that remains unresolved is the overall frequency of peptide-dependent versus peptide-independent alloreactive T cells. We have addressed these questions with antigen-presenting cells (APC) from H2-M mutant mice that predominantly express a single MHC class II-peptide complex, H2-Ab bound by a peptide (CLIP) derived from the class II-associated invariant chain. APC from these mice were used as targets and stimulators for alloreactive CD4+ T cells. Results demonstrated that the vast majority of CD4+ alloreactive T cells recognize MHC class II molecules in a peptide-dependent fashion.

[Study of autoimmunity in progeny of pregnant women with systemic lupus erythematosus]

OBJECTIVE

To study the effect of systemic lupus erythematosus (SLE) on physical, mental development and plasma antibody level of SLE in their progenies.

METHODS

Routine physical examinations of 49 children from 48 SLE mothers were conducted. Compared immuno-fluorescence anti-nuclear antibody (IFANA), anticardiolipin (ACL), extractable nuclear antigen (ENA) and anti-ds-DNA plasma levels of SLE mothers and their progenies with that levels during pregnancy and in umbilical blood.

RESULTS

The physical development (height and weight) in 47 out of 49 children were within normal range while the remaining 2 were in the lower limit. The autoimmune antibodies were all negative in the umbilical blood with autoimmune negative mothers, while the anti-ribonucleoprotein (anti-RNP), anti-Smith surface antigen (anti-SSA), anti-specific soluble ribonucleic acid (anti-SSB) and ACL could be transferred to fetus through placenta. During follow up study, compared the autoimmune positive rates in progenies with that of mothers, the positive rates of IFANA and anti-ds-DNA decreased significantly (P < 0.01), while no changes in ACL. Compared the autoimmune positive rates in progenies with that of their own umbilical levels, the positive rates of IFANA, anti-RNP, anti-SSA decreased significantly (P < 0.01), while no difference existed in ACL. Boys showed faster disappearance of autoimmune positive rates than that of girls.

CONCLUSIONS

SLE did not show significant effects on the physical development of their progenies. Most autoimmune antibodies existed in umbilical blood were transferred through placenta during pregnancy and would disappear within 9 years after birth. Autoimmune antibodies decreased quicker in boys, and it indicated that girls should be follow-up more carefully. Autoimmune antibodies in the umbilical blood is an easy method for the screening of SLE progeny.

[Detection of IgM-antibody to hepatitis G virus and its clinical significance]

OBJECTIVE

To provide a rapid and early serodiagnostic technique for the patients with hepatitis G virus(HGV).

METHODS

A capture ELISA was developed to detect anti-HGV IgM in sera using synthetic peptides of HGV NS3 NS5 gene regions conjugated with horseradish peroxidase.

RESULTS

This assay was not disturbed by competition of specific IgG or interfered by RF and did not cross-react with HAV, HBV, HCV, HEV, CMV and EBV. Among 46 sera of non-A-E hepatitis, 14 were positive for anti-HGVIgM, the positive rate was 30.43%, 6 was positive for HGV RNA the positive rate was 42.86%. 12 paired sera from acute stage of HGV patients were all positive by capture-ELISA.

CONCLUSION

This method is sensitive, specific, rapid and stable for detecting anti-HGV IgM, and is useful in the early diagnosis of HGV infection.

Natural killer cells determine development of allergen-induced eosinophilic airway inflammation in mice

The earliest contact between antigen and the innate immune system is thought to direct the subsequent antigen-specific T cell response. We hypothesized that cells of the innate immune system, such as natural killer (NK) cells, NK1.1(+) T cells (NKT cells), and gamma/delta T cells, may regulate the development of allergic airway disease. We demonstrate here that depletion of NK1.1(+) cells (NK cells and NKT cells) before immunization inhibits pulmonary eosinophil and CD3(+) T cell infiltration as well as increased levels of interleukin (IL)-4, IL-5, and IL-12 in bronchoalveolar lavage fluid in a murine model of allergic asthma. Moreover, systemic allergen-specific immunoglobulin (Ig)E and IgG2a levels and the number of IL-4 and interferon gamma-producing splenic cells were diminished in mice depleted of NK1.1(+) cells before the priming regime. Depletion of NK1.1(+) cells during the challenge period only did not influence pulmonary eosinophilic inflammation. CD1d1 mutant mice, deficient in NKT cells but with normal NK cells, developed lung tissue eosinophilia and allergen-specific IgE levels not different from those observed in wild-type mice. Mice deficient in gamma/delta T cells showed a mild attenuation of lung tissue eosinophilia in this model. Taken together, these findings suggest a critical role of NK cells, but not of NKT cells, for the development of allergen-induced airway inflammation, and that this effect of NK cells is exerted during the immunization. If translatable to humans, these data suggest that NK cells may be critically important for deciding whether allergic eosinophilic airway disease will develop. These observations are also compatible with a pathogenic role for the increased NK cell activity observed in human asthma.

"Dip-Pen" nanolithography

A direct-write "dip-pen" nanolithography (DPN) has been developed to deliver collections of molecules in a positive printing mode. An atomic force microscope (AFM) tip is used to write alkanethiols with 30-nanometer linewidth resolution on a gold thin film in a manner analogous to that of a dip pen. Molecules are delivered from the AFM tip to a solid substrate of interest via capillary transport, making DPN a potentially useful tool for creating and functionalizing nanoscale devices.

[Study on the combination of isotachophoresis and high performance liquid chromatography for the separation of complex samples]

A method on the combination of isotachophoresis (ITP) and high performance liquid chromatography (HPLC) for the separation and analysis of the complex samples containing proteins and metals is proposed. The instrumental system consisted of a self-made Model OCEP-1 isotachophoresis analyser, main parts of Waters high performance liquid chromatograph and a self-made Model IHI-1 interface. The interface is simple and convenient to use. The injection volume of the interface was determined accurately with a neutralization titration method. In ITP experiment the leading electrolyte was 2.5 mmol/L HCl containing 30 mmol/L of 18-crown-6; the terminating electrolyte was 5 mmol/L Tris+Cl-(pH 6.0); ITP current, 40 microA; detection of metal ions, potential gradient detector. In HPLC experiment the column was a mu-Bondapak C18, reversed-phase column, 4 mm x 200 mm, 10 microns, 12.5 nm; the mobile phase A, V(isopropanol with 5% volume fraction):V(butanol) = 2:1 containing 2.2 mmol/L HCl (pH 2.63); the mobile phase B, V(isopropanol with 50% volume fraction):V(butanol) = 2:1; low pressure gradient elution, mobile phase B changed from 0 to 70% in 17.5 minutes; flow rate, 1.0 mL/min; detection wavelength 225 nm; temperature, 25 degrees C. The experimental results showed that proteins were interfered in the determination of the metals with ITP method. It also showed that HPLC with the use of C18 column can separate the proteins but not the metal ions. By using this new combination system, a complex sample of the proteins and metal ions was injected to the HPLC, the proteins Lys, BSA and OVA were well separated in HPLC, while NH4+, K+, Na+, and Ca2+ were less retained and eluted first. Then the latter was introduced into the system of the ITP with the aid of the interface for separation. Satisfactory results were obtained.

[Antigenicity of nine synthetic peptides of human immunodeficiency virus]

To establish a ELISA method to detect the infection of human immunodeficiency virus (HIV), we synthesized nine peptides ranging in length between 10-27 amino acid (aa) of HIV located in the regions of gp41, p24 of HIV-1 and gp36 of HIV-2, according to the published amino acid sequence and the position of antigenic determinants of viruses, by a solid-phase method. We detected 10 positive sera of HIV-1 and 4 positive sera of HIV-2 by a indirect ELISA using these synthetic peptides as the coating antigen. The results indicated that all of 10 serum specimens of HIV-1 were positive using SP1, 5, 6, and 7 derived from gp41, and SP7 was the best in antigenicity. The 4 serum specimens of HIV-2 were positive using SP8 and SP9 in the region of gp36 and their antigenicity to HIV-2 were similar, but the antigenicity of SP8 to HIV-1 was higher than that of SP9. All sera of HIV-1 and HIV-2 were positive using SP7 and SP8 as the mixed coating antigen. A comparison of our reagent with UBI reagent in detection of 60 positive and 96 negative control sera for HIV showed that the coincident rate for positive ness was 98.33% (59/60), for negative ness was 100%, and the general coincident rate was 99.36% (155/156). It is concluded that SP7 and SP8 as the mixed coating antigen are applicable in the diagnosis of HIV infection.

[Specific IgG and specific IgG subclass in allergic rhinitis]

Using enzyme-linked immunosorbent assay, we detected the levels of total IgE, caddis fly specific IgE and caddis fly specific IgG subclass in 60 patients with caddis fly allergic rhinitis. The results showed that the levels of SIgE (30.60 +/- 0.78) of patients were significantly higher than that of the controls (P < 0.001). Same results were received in the levels of specific IgG2 and IgG4. The differences of specific IgE and specific IgG4 between the groups before treatment and after treatment were also significant (Specific IgE before treatment: 30.60 +/- 0.78, after treatment: 1.58 +/- 0.44, P < 0.001; specific IgG4 before treatment: 383.31 +/- 96.48, after treatment: 233.68 +/- 80.94, P < 0.001). We conclude that specific IgG subclass has obviously etiologic specificity and sensitivity.

[Study on the experimental infection of hepatitis G virus in rhesus monkey]

In order to study the experimental infection of HGV in rhesus monkey, the monkeys were infected using the plasma from a donor with HGV RNA positive. The second generation monkeys were infected with the sera of the first generation monkeys infected after 6 weeks, and also the third generation monkeys were infected with the sera of the second generation monkeys. HGV RNA were detected by RT-nPCR. The results showed that in sera of infected monkeys HGV RNA were positive after 1 week of inoculation, and were consecutively positive for up to 28 weeks at longest. The level of ALT raised a little in monkey No. 1 and higher than 100 U/L in No. 5. The liver biopsy showed viral hepatitis--like histological changes. Comparing the sequence of HGV 5'LTR from sera of the infected monkeys and the blood donor, the homogeneity, to strain HGU44402 was 98.33% and 95.83% to strain HGU36380 was 92.50% and 89.17%, respectively. The results suggested that the rhesus monkey is sensitive to HGV and is suitable for establishment of an animal model.

Heavy metals in antarctic ice from Law Dome: initial results

Pb, Cd, Cu, and Zn have been measured using ultraclean procedures in eight sections taken from two well-dated ice cores from Law Dome, an independent small size ice cap with high accumulation rate situated in the coastal area of East Antarctica. Seven sections were dated from the 1830s to 1940s and one was dated from three millennia ago. The data show that there are strong seasonal variations in the concentrations of Pb and Cd, with values approximately tow-to fourfold higher in winter than in spring-summer. Evaluation of the contributions from the different sources suggests that contribution from sea salt spray is relatively important, especially for Cd. Contribution from marine biogenic emissions could also be very significant. The importance of marine contributions is consistent with strong intrusions of marine air masses at this coastal site, especially during wintertime.