Human alphaA- and alphaB-crystallins bind to Bax and Bcl-X(S) to sequester their translocation during staurosporine-induced apoptosis

AlphaA- and alphaB-crystallins are distinct antiapoptotic regulators. Regarding the antiapoptotic mechanisms, we have recently demonstrated that alphaB-crystallin interacts with the procaspase-3 and partially processed procaspase-3 to repress caspase-3 activation. Here, we demonstrate that human alphaA- and alphaB-crystallins prevent staurosporine-induced apoptosis through interactions with members of the Bcl-2 family. Using GST pulldown assays and coimmunoprecipitations, we demonstrated that alpha-crystallins bind to Bax and Bcl-X(S) both in vitro and in vivo. Human alphaA- and alphaB-crystallins display similar affinity to both proapoptotic regulators, and so are true with their antiapoptotic ability tested in human lens epithelial cells, human retina pigment epithelial cells (ARPE-19) and rat embryonic myocardium cells (H9c2) under treatment of staurosporine, etoposide or sorbitol. Two prominent mutants, R116C in alphaA-crystallin and R120G, in alphaB-crystallin display much weaker affinity to Bax and Bcl-X(S). Through the interaction, alpha-crystallins prevent the translocation of Bax and Bcl-X(S) from cytosol into mitochondria during staurosporine-induced apoptosis. As a result, alpha-crystallins preserve the integrity of mitochondria, restrict release of cytochrome c, repress activation of caspase-3 and block degradation of PARP. Thus, our results demonstrate a novel antiapoptotic mechanism for alpha-crystallins.

Symmetric-to-asymmetric transition in triblock copolymer-homopolymer blends

In blends of a symmetric poly(styrene-ethylene/butylene-styrene) tri-block-copolymer with a polystyrene homopolymer, small-angle x-ray scattering and cryotransmission electron microscopy measurements reveal a microstructure consisting of a disordered arrangement of poly(ethylene/butylene) membranes suspended in polystyrene. For triblock volume fractions less than 0.22, the membranes form an asymmetric sponge or L4 phase, consisting predominantly of equilibrium vesicles. For volume fractions greater than 0.22, they form a symmetric sponge-phase (L3 phase), separated from the L4 phase by a first-order transition.

Downhill skiing injury fatalities among children

OBJECTIVE

Young skiers are at increased risk for injury, however, epidemiological data on skiing related fatal injuries among child skiers are scarce. This study aimed to provide information needed to develop injury control and prevention programs.

DESIGN AND SETTING

Study subjects came from Colorado, USA and were identified using a death certificate based surveillance system. Fatal injuries were limited to events that occurred at established commercial ski resorts in Colorado, and subjects were classified as child skiers (0-17 years) or adult skiers (> or =18 years).

MAIN OUTCOME MEASURE

Type and external cause, time, and week day of injury, gender and residency of the decedents.

RESULTS

During the study period from 1980-2001, 149 fatal injuries associated with downhill skiing were identified; 21 (14.1%) occurred among child skiers aged < or =17 years. The age of the youngest decedent was 7 years. In females the proportion of fatal injuries among child skiers was nearly three times that of adults. Traumatic brain injuries were the leading cause of death (67% of all deaths) among children, while multiple internal injuries and traumatic brain injuries accounted for almost equal proportions of fatal injuries among adults. Collision was the leading external mechanism of fatal injuries, accounting for more than two thirds of fatal injuries in both child and adult skiers.

CONCLUSIONS

Traumatic brain injury was the leading cause and collision was the leading external injury mechanism of fatal injuries associated with downhill skiing among child skiers. This underscores the importance of brain injury prevention strategies, including the use of ski helmets and prevention of collisions on ski slopes.

Total enzymatic synthesis of cholecystokinin CCK-5

This paper describes the enzymatic synthesis of the C-terminal fragment H-Gly-Trp-Met-Asp-Phe-NH2 of cholecystokinin. Immobilized enzymes were used for the formation of all peptide bonds except thermolysin. Beginning the synthesis with phenylacetyl (PhAc) glycine carboxamidomethyl ester (OCam) and H-Trp-OMe by using immobilized papain as biocatalyst in buffered ethyl acetate, the dipeptide methyl ester was then coupled directly with Met-OEt.HCl by alpha-chymotrypsin/Celite 545 in a solvent free system. For the 3+2 coupling PhAc-Gly-Trp-Met-OEt had to be converted into its OCam ester. The other fragment H-Asp(OMe)-Phe-NH2 resulted from the coupling of Cbo-Asp(OMe)-OH with H-Phe-NH2.HCl and thermolysin as catalyst, followed by catalytic hydrogenation. Finally PhAc-Gly-Trp-Met-Asp-Phe-NH2 was obtained in a smooth reaction from PhAc-Gly-Trp-Met-OCam and H-Asp(OMe)-Phe-NH2 with alpha-chymotrypsin/Celite 545 in acetonitrile, followed by basic hydrolysis of the beta-methyl ester. The PhAc-group is removed with penicillin G amidase and CCK-5 is obtained in an overall isolated yield of 19.6%.

Precision measurement of the neutron spin asymmetryA(n)(1) and spin-flavor decomposition in the valence quark region

We have measured the neutron spin asymmetry A(n)(1) with high precision at three kinematics in the deep inelastic region at x=0.33, 0.47, and 0.60, and Q(2)=2.7, 3.5, and 4.8 (GeV/c)(2), respectively. Our results unambiguously show, for the first time, that A(n)(1) crosses zero around x=0.47 and becomes significantly positive at x=0.60. Combined with the world proton data, polarized quark distributions were extracted. Our results, in general, agree with relativistic constituent quark models and with perturbative quantum chromodynamics (PQCD) analyses based on the earlier data. However they deviate from PQCD predictions based on hadron helicity conservation.

Cross-section measurement of charged-pion photoproduction from hydrogen and deuterium

We have measured the differential cross section for the gamman-->pi(-)p and gammap-->pi(+)n reactions at theta(c.m.)=90 degrees in the photon energy range from 1.1 to 5.5 GeV at Jefferson Lab (JLab). The data at E(gamma) greater, similar 3.3 GeV exhibit a global scaling behavior for both pi(-) and pi(+) photoproduction, consistent with the constituent counting rule and the existing pi(+) photoproduction data. Possible oscillations around the scaling value are suggested by these new data. The data show enhancement in the scaled cross section at a center-of-mass energy near 2.2 GeV. The cross section ratio of exclusive pi(-) to pi(+) photoproduction at high energy is consistent with the prediction based on one-hard-gluon-exchange diagrams.

Role of active site binding interactions in 4-chlorobenzoyl-coenzyme A dehalogenase catalysis

4-Chlorobenzoyl-coenzyme A (4-CBA-CoA) dehalogenase catalyzes the hydrolytic dehalogenation of 4-CBA-CoA to 4-hydroxybenzoyl-CoA (4-HBA-CoA) via a multistep mechanism involving initial attack of Asp145 on C(4) of the substrate benzoyl ring to form a Meisenheimer intermediate (EMc), followed by expulsion of the chloride ion to form an arylated enzyme intermediate (EAr) and then ester hydrolysis in the EAr to form product. This study examines the role of binding interactions in dehalogenase catalysis. The enzyme and substrate groups positioned for favorable binding interaction were identified from the X-ray crystal structure of the enzyme-4-HBA-3'-dephospho-CoA complex. These groups were individually modified (via site-directed mutagenesis or chemical synthesis) for the purpose of disrupting the binding interaction. The changes in the Gibbs free energy of the enzyme-substrate complex (DeltaDeltaG(ES)) and enzyme-transition state complex (DeltaDeltaG) brought about by the modification were measured. Cases where DeltaDeltaG exceeds DeltaDeltaG(ES) are indicative of binding interactions used for catalysis. On the basis of this analysis, we show that the H-bond interactions between the Gly114 and Phe64 backbone amide NHs and the substrate benzoyl C=O group contribute an additional 3.1 kcal/mol of stabilization at the rate-limiting transition state. The binding interactions between the enzyme and the substrate CoA nucleotide moiety also intensify in the rate-limiting transition state, reducing the energy barrier to catalysis by an additional 3.3 kcal/mol. Together, these binding interactions contribute approximately 10(6) to the k(cat)/K(m).

Antilambda production in Au+Au collisions at 11.7A GeV/c

We present results for antilambda and antiproton production in Au+Au collisions at 11.7 A GeV/c including spectra and extracted invariant yields for both species in central and peripheral collisions in the rapidity range 1.0<y<1.4. The antilambda yield increases from dN(Lambda;)/dy = 1.2(+0.7+0.2)(-0.6-0.2)x10(-3) in peripheral collisions to 19(+4+3)(-5-2)x10(-3) in central collisions. The direct antiproton yield is deduced from the measured total antiproton spectra to extract the ratio of antilambda-to-direct-antiproton production. The Lambda/p ratio near midrapidity increases from 0.26(+0.19+0.5)(-0.15-0.4) in peripheral collisions to 3.6(+4.7+2.7)(-1.8-1.1) in central collisions, a value larger than current theoretical estimates.

Human bcl-2 gene attenuates the ability of rabbit lens epithelial cells against H2O2-induced apoptosis through down-regulation of the alpha B-crystallin gene

It is well established that the proto-oncogene, bcl-2, can prevent apoptosis induced by a variety of factors. Regarding the mechanism by which BCL-2 prevents cell death, one theory suggests that it acts by protecting cells from oxidative stress. In the lens system, oxidative stress-induced apoptosis is implicated in cataractogenesis. To explore the possibility of anti-apoptotic gene therapy development for cataract prevention and also to further test the anti-oxidative stress theory of BCL-2 action, we have introduced the human bcl-2 gene into an immortalized rabbit lens epithelial cell line, N/N1003A. The stable expression clones of both vector- and bcl-2-transfected cells have been established. Treatment of the two cell lines with H(2)O(2) revealed that bcl-2-transfected cells were less capable of detoxifying H(2)O(2) than the control cells. Moreover, bcl-2-transfected cells are more susceptible to H(2)O(2)-induced apoptosis. To explore why bcl-2-transfected cells have reduced resistance to H(2)O(2)-induced apoptosis, we examined the expression patterns of several relevant genes and found that expression of the alphaB-crystallin gene was distinctly down-regulated in bcl-2-transfected cells compared with that in vector-transfected cells. This down-regulation was specific because a substantial inhibition of BCL-2 expression through antisense bcl-2 RNA significantly restored the level of alphaB-crystallin and, moreover, enhanced the ability of the bcl-2-transfected cells against H(2)O(2)-induced apoptosis. Introduction of a mouse alphaB-crystallin gene into bcl-2-transfected cells also counteracted the BCL-2 effects. Down-regulation of alphaB-crystallin gene was largely derived from changed lens epithelial cell-derived growth factor activity. Besides, alphaB-crystallin prevents apoptosis through interaction with procaspase-3 and partially processed procaspase-3 to prevent caspase-3 activation. Together, our results reveal that BCL-2 can regulate gene expression in rabbit lens epithelial cells. Through down-regulation of the alphaB-crystallin gene, BCL-2 attenuates the ability of rabbit lens epithelial cells against H(2)O(2)-induced apoptosis.

Analysis of expression patterns of protein phosphatase-1 and phosphatase-2A in rat and bovine lenses

PURPOSE

The reversible phosphorylation and dephosphorylation at the serine and threonine residues on proteins play distinct roles in regulating multiple cellular activities. Whereas the protein serine-threonine kinases have been well studied in the lens system, very little is known about the expression and function of the serine-threonine phosphatases. The present article reports the expression patterns of protein phosphatase (PP)-1 and -2A in adult rat and bovine lenses.

METHODS

Total RNAs and proteins were extracted from the epithelial and fiber cells of rat and bovine lenses. RT-PCR and Northern blot analysis were used to detect the mRNA expression levels in the epithelial cells and different fractions of fiber cells of these two types of lenses. Western blot was used to examine the protein expression levels in these different samples. An enzymatic assay was used to detect the activity distribution of PP-1 and -2A in these samples.

RESULTS

The mRNAs for the PP-1 catalytic subunit (PP-1cs) and PP-2A catalytic subunit (PP-2Acs) were expressed in both epithelial and fiber cells of rat and bovine lenses. A detailed examination of the expression patterns of the two mRNAs in different fractions of fiber cells revealed that the cortical fiber cells (F1) contain the highest level of PP-1cs and -2Acs mRNAs (similar to those in the epithelial cells) among different fractions of fiber cells. The levels of the two mRNAs were sequentially decreased in the next layers of fiber cells (F2 and F3) and became barely detectable in the inner layers of fiber cells (F4 and N). In contrast to the mRNA expression patterns, the PP-1cs protein was mainly found in the epithelial cells. Among different layers of fiber cells, only cortical (F1) fiber cells contained detectable level of PP-1cs protein (bovine lenses contained a relatively higher level of PP-1cs than rat lenses in this region). In the remaining fiber cells, the PP-1cs protein was hardly detectable in rat lenses and slightly detectable in bovine lenses. The PP-2Acs protein was detectable only in the lens epithelial cells. Enzymatic assays revealed that the distribution patterns of PP-1 and -2A activities were similar to those of PP-1cs and -2Acs proteins. Furthermore, PP-1 activity was approximately four to five times higher than PP-2A activity in the lens epithelial cells.

CONCLUSIONS

This study demonstrates that active PP-1 and -2A are mainly distributed in the lens epithelial cells, with PP-1 as a major phosphatase. The mRNAs and proteins for PP-1cs and -2Acs are differentially expressed in the epithelial and fiber cells of rat and bovine lenses.

[Study on factor IX gene mutation in 74 hemophilia B patients]

OBJECTIVE

To investigate the distribution of the FIX gene mutations in hemophilia B(HB) and compare the mutation patterns between the Chinese HB and Caucasian HB.

METHOD

Genomic DNA was extracted from the blood samples of HB patients. Nine DNA segments of the FIX gene were amplified. Gene mutations of the amplified DNA segments were detected by direct sequencing.

RESULT

Fifty eight independent mutations were detected and identified in 69 HB patients. Among them twenty nine mutations were novel and not reported before. A similar pattern of germline mutation was found in both Chinese HB and Caucasian HB patients.

CONCLUSION

No difference was observed in mutation patterns between Chinese and Caucasian HB.

Identification, Substrate Specificity, and Inhibition of theStreptococcus pneumoniae β-Ketoacyl-Acyl Carrier Protein Synthase III (FabH)

In the bacterial type II fatty acid synthase system, beta-ketoacyl-acyl carrier protein (ACP) synthase III (FabH) catalyzes the condensation of acetyl-CoA with malonyl-ACP. We have identified, expressed, and characterized the Streptococcus pneumoniae homologue of Escherichia coli FabH. S. pneumoniae FabH is approximately 41, 39, and 38% identical in amino acid sequence to Bacillus subtilis, E. coli, and Hemophilus influenzae FabH, respectively. The His-Asn-Cys catalytic triad present in other FabH molecules is conserved in S. pneumoniae FabH. The apparent K(m) values for acetyl-CoA and malonyl-ACP were determined to be 40.3 and 18.6 microm, respectively. Purified S. pneumoniae FabH preferentially utilized straight short-chain CoA primers. Similar to E. coli FabH, S. pneumoniae FabH was weakly inhibited by thiolactomycin. In contrast, inhibition of S. pneumoniae FabH by the newly developed compound SB418011 was very potent, with an IC(50) value of 0.016 microm. SB418011 also inhibited E. coli and H. influenzae FabH with IC(50) values of 1.2 and 0.59 microm, respectively. The availability of purified and characterized S. pneumoniae FabH will greatly aid in structural studies of this class of essential bacterial enzymes and facilitate the identification of small molecule inhibitors of type II fatty acid synthase with the potential to be novel and potent antibacterial agents active against pathogenic bacteria.

Caspase-3 is actively involved in okadaic acid-induced lens epithelial cell apoptosis

Phosphorylation and dephosphorylation are important cellular events regulating major metabolic activities such as signal transduction, gene expression, cell cycle progression, and apoptosis. It is well documented that okadaic acid, a potent inhibitor of protein phosphatase-1 (PP-1) and -2A (PP-2A), can induce apoptosis in a variety of cell lines. Our recent studies have revealed that in the immortal rabbit lens epithelial cell line, N/N1003A, inhibition of PP-1, but not PP-2A, leads to rapid apoptosis of the lens epithelial cells. This induction of cell death is associated with up-regulated expression of a set of genes, including the tumor-suppressor gene, p53, and the proapoptotic gene, bax. In the present study, we demonstrate that inhibition of PP-1 by okadaic acid in the primary cultures of rat lens epithelial cells also leads to apoptotic death. Moreover, we show that the cysteine protease, caspase-3, is important in the execution of okadaic acid-induced apoptosis. Treatment of the primary cultures of rat lens epithelial cells with 100 nM okadaic acid up-regulates expression of caspase-3 at the mRNA, protein, and enzyme activity levels. Inhibition of the caspase-3 activity with a chemically synthesized inhibitor prevents okadaic acid-induced apoptosis in rat lens epithelial cells. Similar results are also observed in the immortal cell line N/N1003A. Furthermore, stable expression of the mouse gene encoding lens alphaB crystallin inhibits okadaic acid-induced apoptosis, and this inhibition is associated with repression of the okadaic acid-induced up-regulation of caspase-3 activity. Taken together, these results demonstrate that caspase-3 is actively involved in okadaic acid-induced lens epithelial cell apoptosis.

[An inquiry into the relationship among pathology, clinic and laboratory indexes of the severe viral hepatitis]

OBJECTIVE

This study was to analyze the relationship among pathology, clinic and laboratory indexes in 62 cases of the acute severe hepatitis (ASH) and 72 cases of the subacute severe hepatitis(SSH) to offer a correct diagnosis and recognition of the disease.

METHODS

A total of 134 severe hepatitis cases with confirmed pathology treated in a course of 24 years were analyzed by programs of EXCEL 2000.

RESULTS

When compared ASH with SSH, the onset of the age were 40 +/- 13 years old and 44 +/- 15 years old, P < 0.05, the rates of hepatitis coma were 100% and 66.7% respectively. The liver weight of all the cases decreased. The tests of TBiL, PTA, Cho, NH3 and WBC between ASH and SSH had significant differences.

CONCLUSION

Hepatic encephalopathy is a necessary criterion for ASH. The TBiL, PTA and Cho changes are closely related with severe viral hepatitis, they not only are the essential laboratory indexes but also the indispensable factors for disease development and prognosis of severe viral hepatitis.

pH-induced conformational transitions of a molten-globule-like state of the inhibitory prodomain of furin: implications for zymogen activation

The endoprotease furin, which belongs to the family of mammalian proprotein convertase (PC), is synthesized as a zymogen with an N-terminal, 81-residue inhibitory prodomain. It has been shown that the proenzyme form of furin undergoes a multistep 'autocatalytic' removal of the prodomain at the C-terminal side of the two consensus sites, R(78)-T-K-R(81) approximately and R(44)-G-V-T-K-R(49) approximately. The furin-mediated cleavage at R(44)-G-V-T-K-R(49) approximately, in particular, is significantly accelerated in an 'acidic' environment. Here, we show that under neutral pH conditions, the inhibitory prodomain of furin is partially folded and undergoes conformational exchanges as indicated by extensive broadening of the NMR spectra. Presence of many ring-current shifted methyl resonances suggests that the partially folded state of the prodomain may still possess a 'semirigid' protein core with specific packing interactions among amino acid side chains. Measurements of the hydrodynamic radii and compaction factors indicate that this partially folded state is significantly more compact than a random chain. The conformational stability of the prodomain appears to be pH sensitive, in that the prodomain undergoes an unfolding transition towards acidic conditions. Our NMR analyses establish that the acid-induced unfolding is mainly experienced by the residues from the C-terminal half of the prodomain (residues R(44)-R(81)) that contains the two furin cleavage sites. A 38-residue peptide fragment derived from the entire pH-sensitive C-terminal region (residues R(44)-R(81)) does not exhibit any exchange-induced line broadening and adopts flexible conformations. We propose that at neutral pH, the cleavage site R(44)-G-V-T-K-R(49) approximately is buried within the protein core that is formed in part by residues from the N-terminal region, and that the cleavage site becomes exposed under acidic conditions, leading to a facile cleavage by the furin enzyme.

Baryon rapidity loss in relativistic Au + Au collisions

An excitation function of proton rapidity distributions for different centralities is reported from AGS Experiment E917 for Au+Au collisions at 6, 8, and 10.8 GeV/nucleon. The rapidity distributions from peripheral collisions have a valley at midrapidity which smoothly change to distributions that display a broad peak at midrapidity for central collisions. The mean rapidity loss increases with increasing beam energy, whereas the fraction of protons consistent with isotropic emission from a stationary source at midrapidity decreases with increasing beam energy. The data suggest that the stopping is substantially less than complete at these energies.

hTERT can function with rabbit telomerase RNA: regulation of gene expression and attenuation of apoptosis

Telomerase is a specialized DNA polymerase that adds telomeric sequences onto chromosome ends. The functional telomerase complex contains a telomerase reverse transcriptase (TERT) and also a telomerase RNA (TR). Although it is well established that the human telomerase reverse transcriptase (hTERT) can function well in different human cell lines, it has not been shown whether it is compatible with telomerase template RNA from other species. Here we report that the expressed hTERT is functionally compatible with rabbit telomerase template RNA (rTR) as demonstrated by TRAP assay. The direct interaction between hTERT and rTR is further confirmed by immunoprecipitation-linked RT-PCR in which rTR is detected from the complex immunoprecipitated by an anti-hTERT antibody. The hTERT expressed in rabbit lens epithelial cells demonstrates two major functions: modulation of expression of other genes and attenuation of apoptosis. Thus, telomerase has a variety of functions besides telomere synthesis, and the template RNA is functionally conserved between human and rabbit.

An A245T mutation conveys on cytochrome P450eryF the ability to oxidize alternative substrates

Cytochrome P450(eryF) (CYP107A1), which hydroxylates deoxyerythronolide B in erythromycin biosynthesis, lacks the otherwise highly conserved threonine that is thought to promote O-O bond scission. The role of this threonine is satisfied in P450(eryF) by a substrate hydroxyl group, making deoxyerythronolide B the only acceptable substrate. As shown here, replacement of Ala(245) by a threonine enables the oxidation of alternative substrates using either H(2)O(2) or O(2)/spinach ferredoxin/ferredoxin reductase as the source of oxidizing equivalents. Testosterone is oxidized to 1-, 11alpha-, 12-, and 16alpha-hydroxytestosterone. A kinetic solvent isotope effect of 2.2 indicates that the A245T mutation facilitates dioxygen bond cleavage. This gain-of-function evidence confirms the role of the conserved threonine in P450 catalysis. Furthermore, a Hill coefficient of 1.3 and dependence of the product distribution on the testosterone concentration suggest that two testosterone molecules bind in the active site, in accord with a published structure of the P450(eryF)-androstenedione complex. P450(eryF) is thus a structurally defined model for the catalytic turnover of multiply bound substrates proposed to occur with CYP3A4. In view of its large active site and defined structure, catalytically active P450(eryF) mutants are also attractive templates for the engineering of novel P450 activities.

Agricultural work-related injuries among farmers in Hubei, People's Republic of China

OBJECTIVES

This population-based study evaluated patterns of and risk factors for, agricultural injuries among farmers in the People's Republic of China.

METHODS

A multistage sample of 1500 Chinese farmers was selected from 14 villages. Face-to-face interviews with 1358 farmers were conducted between July 1997 and September 1997 (response rate = 91%). Agricultural work-related injuries that occurred in the previous 24 months and the associated factors were evaluated.

RESULTS

A total of 33% of the farmers reported at least 1 work-related injury in the 24 months before the survey. Major external causes of the injuries were hand tools (50%), falls (26%), and heavy falling objects (10%). The statistically significant risk factors for injury were low family income, 1 to 6 school years of education, self-reported pesticide exposure, tension in relationships with neighbors, and stress in life. The most notable result was the relation between self-reported pesticide exposure and injury, with farmers with greater pesticide exposure at significantly greater risk for injury.

CONCLUSIONS

The results of this study indicated that injuries occurring among Chinese farmers may have unique patterns and potential risk factors.

[Determination of nickel based on the fluorescence quenching of phenanthroline]

A new selective and sensitive spectrofluorimetric method for the determination of trace amounts of nickel in industrial waste water has been developed. This method is based on the quenching of fluorescence of phenanthroline due to the formation of complex Ni (II)-Phen. The exitation and emission wavelengths were found to be 272 and 366 nm, respectively. There was a linear relationship in the range of 10.0-120 ng.mL-1 for Ni. This method is simple and rapid, and has been applied to the determination of nickel in industrial waste water.

The active-site residue Cys-29 is responsible for the neutral-pH inactivation and the refolding barrier of human cathepsin B

Human cathepsin B, the most abundant lysosomal cysteine protease, has been implicated in a variety of important physiological and pathological processes. It has been known for a long time that like other lysosomal cysteine proteases, cathepsin B becomes inactivated and undergoes irreversible denaturation at neutral or alkaline pH. However, the mechanism of this denaturation process remains mostly unknown up to this day. In the present work, nuclear magnetic resonance spectroscopy was used to characterize the molecular origin of the neutral-pH inactivation and the refolding barrier of human cathepsin B. Two forms of human cathepsin B, the native form with Cys-29 at the active site and a mutant with Cys-29 replaced by Ala, were shown to have well-folded structures at the active and slightly acidic condition of pH 5. Surprisingly, while the native cathepsin B irreversibly unfolds at pH 7.5, the C29A mutant was found to maintain a stable three-dimensional structure at neutral pH conditions. In addition, replacement of Cys-29 by Ala renders the process of the urea denaturation of human cathepsin B completely reversible, in contrast to the opposite behavior of the wild-type cathepsin B. These results are very surprising in that replacement of one single residue, the active-site Cys-29, can eliminate the neutral-pH denaturation and the refolding barrier. We speculate that this finding may have important implications in understanding the process of pH-triggered inactivation commonly observed for most lysosomal cysteine proteases.

[A new strategy of gene therapy for hyperphenylalaninemia rats]

OBJECTIVE

To construct a recombinant vector which expresses active phenylalanine-amonia-lyase (PAL) in Lactococcus lactis (L. L.), and to convert phe into cinnamic acid in small intestine by the engineering L. L. to decrease the phe level in the peripheral blood, and to cure hyperphenylalaninemia rats.

METHODS

PAL cDNA from Petroselinum crispum was subcloned into expression vector pMG36e and transformed L. L. The pMG36ePAL/L.L. was screened and characterized by using PCR and HPLC, and prepared as enteric-coated microcapsules and oral liquid type preparation that were given orally to hyperphenylalaninemia-rats.

RESULTS

Engineering L. L. expressing PAL activity was obtained. The phe levels plasma of in the rats receiving preparations made from the engineering L. L. were significantly reduced compared with non-treated hyperphenylalaninemia rats. And the effects of different preparations were different from each other.

CONCLUSION

The engineering L. L. expressing PAL activity can reduce the blood phe level of the hyperphenylalaninemia rats. This may be a potential way for PKU gene therapeutics.

Human glutathione-S-transferase: cloning and expression in Lactococcus lactis

The glutathione-S-transferase A1 cDNA was amplified from the total RNAs of human liver by RT-PCR, and inserted into plasmid pMG36e. The hGSTA1 was expressed in Lactococcus lactis MG1363 and verified by SDS-PAGE and Western blot, purified by affinity chromatography and showed enzymatic activity.

[Expression and activity analysis of the human glutathione-S-transferase in Lactococcus lactis]

The glutathione-S-transferase A1 cDNA was amplified from human liver total RNAs by RT-PCR and was cloned into a Escherichia coli expression vector pET23b, then the recombinant plasmid pET23bhgst was introduced into E. coli BL21 (DE3) and induced by IPTG, the high-level expression of hGSTA1 appeared in the E. coli cells. The cDNA encoding hGSTA1 was subcloned into pMG36e, a lactococcal expression vector, and introduced into Lactococcus lactis MG1363 by electroporation. In the positive transformants, the hGSTA1 was expressed as a fusion protein which was verified by SDS-PAGE and Western blot. The hGSTA1 from both E. coli and L. lactis was purified by affinity chromatography on glutathione-agarose and all showed enzymatic activity. The potential application of the recombinant Lactococcus lactis in functional food was also discussed.

A geographic information assessment of birth weight and crop production patterns around mother's residence

A landscape approach using remote sensing (RS) and geographic information system (GIS) technologies was developed to identify the proximity of maternal residence to agricultural areas, and the association between crop production patterns around mothers residences and low birth weight was evaluated. Satellite data obtained for Weld County, Colorado, in 1991 and 1993 were digitally processed to generate crop location maps for this study. GIS procedures were then used to determine crop types within 300- and 500-m circular zones around mothers' homes for 125 births that occurred from 1991 to 1993 in the study area. The relationships between different crop patterns around the mothers' residences and the birth weight of babies were investigated while controlling for potential confounding variables. The results indicated that low birth weight was associated with total crop production area within a 300-m buffer zone around mothers' residences (P=0.058). When each of the study crops was considered separately, low birth weight was associated with sugar beet production (P=0.05) and corn production (P=0.1) within both the 300- and the 500-m buffer zones. This RS/GIS approach provides clues to the potential relationships between birth weight and crop production near the residence.

[Cloning and expression of human Cu/Zn superoxide dismutase gene in Lactococcus lactis]

The cDNA encoding human Cu/Zn SOD was amplified by RT-PCR using the total RNA of human liver as the template, and was cloned into an E. coli expression vector pET23b. After the DNA sequence was determined, the recombinant plasmid pET23bsod was introduced into E. coli BL21(DE3)/pLysS. SDS-PAGE analysis revealed that the recombinant E. coli expressed the predicted 19 kDa human Cu/Zn SOD, and its amount was over 50% of total proteins. The Cu/Zn SOD cDNA was then subcloned into a lactococcal expression vector pMG36e, and resulting pMG36esod was introduced into L. lactis MG1363 by electroporation. The human Cu/Zn-SOD was expressed up to 5% of the soluble proteins, and the enzymatic activity was also observed by SOD activity dying.

[Detection of P wave through wavelet transform and neural network]

The ECG signal is decomposed throught wavelet transform, and then P of the ECG signal wave is detected by neural network. This method has been used as a supplement with satisfactory result. It is of importance to HRV analysis.

Cigarette smoking among medical college students in Wuhan, People's Republic of China

BACKGROUND

This study examined cigarette smoking among a sample of medical college students in Wuhan, People's Republic of China. Specific cultural factors associated with cigarette smoking in China were discussed and issues which need to be studied in the future are presented.

METHODS

A self-administrated questionnaire was administered to a sample of 1,611 medical students in 1995. Smoking status was based on self-reported use of cigarettes within the preceding 180 days. Information about demographic characteristics, home residence, annual family income, and smoking status of family members was also obtained.

RESULTS

A total of 1,540 (1,201 males and 339 females) completed and returned the questionnaires (response rate 95.6%). None of the 339 female students surveyed reported cigarette smoking. A total of 37.7% (95% confidence interval (CI) = 35.0-40.5%) of the male medical students were current smokers, and 5. 3% (95% CI = 4.0-6.6%) were former smokers. The mean age of beginning to smoke was 16.5 years (95% CI = 8.7-24.3 years). The major reasons for first smoking were stress (42.8%, 95% CI = 38.2-47. 4%), curiosity (34.4%, 95% CI = 29.6-38.4%), and loneliness (33.7%, 95% CI = 28.7-37.4%). Multivariate analyses suggested that age, college year, and having a family member who smoked were significantly associated with cigarette smoking.

CONCLUSIONS

The results indicated a need to provide comprehensive tobacco use prevention programs among medical students.

Interchange of catalytic activity within the 2-enoyl-coenzyme A hydratase/isomerase superfamily based on a common active site template

The structures and chemical pathways associated with the members of the 2-enoyl-CoA hydratase/isomerase enzyme superfamily are compared to show that a common active site design provides the members of this family with a CoA binding site, an expandable acyl binding pocket, an oxyanion hole for binding/polarizing the thioester C=O, and multiple active site stations for the positioning of acidic and basic amino acid side chains for use in proton shuttling. It is hypothesized that this active site template can be tailored to catalyze a wide range of chemical transformations through strategic positioning of acid/base residues among the active site stations. To test this hypothesis, the active site of one member of the 2-enoyl-CoA hydratase/isomerase family, 4-chlorobenzoyl-CoA dehalogenase, was altered by site-directed mutagenesis to include the two glutamate residues functioning in acid/base catalysis in a second family member, crotonase. Catalysis of the syn hydration of crotonyl-CoA, absent in the wild-type 4-chlorobenzoyl-CoA dehalogenase, was shown to occur with the structurally modified 4-chlorobenzoyl-CoA dehalogenase at kcat = 0.06 s-1 and Km = 50 microM.

[Expression in Lactococcus lactis of catalytically active phenylalanine ammonia-lyase from parsley]

The phenylalanine ammonia-lyase (PAL) cDNA of parsley (Petroselinum crispum) was subcloned into constitutive expression vector pMG36e downstream of the P32 promoter. The resulting plasmid pMG36ePAL was introduced into Lactococcus lactis subsp. lactis MG1363 by electroporation. The recombinant strain showed its PAL activity conversing the L-phenylalanine in the culture medium into trans-cinnamic acid. A new secretory vector pXHS was constructed by recombination of pMG36e with a Lactococcal usp45 secretion leader coding sequence and a translational coupling sequence. Then the pXHSPAL was constructed and used for expression of PAL in L. lactis, the PAL activity was also detectable. The L. lactis dnaJ promoter sequence was cloned and used to construct a heat inducible vector pXHJ. PAL cDNA was cloned into pXHJ and the L. lactis IL1403 was transformed with the recombinant plasmid pXHJPAL. After a heat shock from 30 degrees C to 37 degrees C, the PAL activity of the pXHJPAL strain could increase approximately onefold. The prospect of using these engineering L. lactis strains for PKU therapy was also discussed.

Conformation of a Cdc42/Rac interactive binding peptide in complex with Cdc42 and analysis of the binding interface

Most of the putative effectors for the Rho-family small GTPases Cdc42 and Rac share a common sequence motif referred to as the Cdc42/Rac interactive binding (CRIB) motif. This sequence, with a consensus of I-S-x-P-(x)2-4-F-x-H-x-x-H-V-G [Burbelo, P. D., et al. (1995) J. Biol. Chem. 270, 29071-29074], has been shown to be essential for the functional interactions between these effector proteins and Cdc42. We have characterized the interactions of a 22-residue CRIB peptide derived from human PAK2 [PAK2(71-92)] with Cdc42 using proton and heteronuclear NMR spectroscopy. This CRIB peptide binds to GTP-gammaS-loaded Cdc42 in a saturable manner, with an apparent Kd of 0.6 microM, as determined by fluorescence titration using sNBD-labeled Cdc42. Interaction of the 22-residue peptide PAK2(71-92) with GTP-gammaS-loaded Cdc42 causes resonance perturbations in the 1H-15N HSQC spectrum of Cdc42 that are similar to those observed for a longer (46-amino acid) CRIB-containing protein fragment [Guo, W., et al. (1998) Biochemistry 37, 14030-14037]. Proton NMR studies of PAK2(71-92) demonstrate structuring of PAK2(71-92) in the presence of GTP-gammaS-loaded Cdc42, through the observation of many nonsequential transferred NOEs. Structure calculations based on the observed transferred NOEs show that the central portion of the Cdc42-bound CRIB peptide assumes a loop conformation in which the side chains of consensus residues Phe80, His82, Ile84, His85, and Val86 are brought into proximity. The CRIB motif may therefore represent a minimal interfacial region in the complexes between Cdc42 and its effector proteins.

Contribution of p53-dependent caspase activation to neuronal cell death declines with neuronal maturation

Caspases play a pivotal role in neuronal cell death during development and after trophic factor withdrawal. However, the mechanisms regulating caspase activity and the role played by caspase activation in response to neuronal injury is poorly understood. The tumor suppressor gene p53 has been implicated in the loss of neuronal viability caused by excitotoxic and DNA damaging agents. In the present study we determined if p53-mediated neuronal cell death required caspase activation. DNA damage increased caspase activity in both cultured embryonic telencephalic and postnatal cortical neurons in a p53-dependent manner. Caspase inhibitors protected embryonic telencephalic neurons, but not postnatal cortical neurons, from DNA damage-induced cell death as measured by direct cell counting and annexin V staining. In marked contrast to the caspase inhibitors, an inhibitor of the DNA repair enzyme, poly(ADP-ribose) polymerase, conferred significant protection from genotoxic and excitotoxic cell death on postnatal cortical neurons but had no effect on embryonic neurons. Glutamate-mediated excitotoxicity in postnatal neurons was not associated with measurable changes in caspase activity, consistent with the failure of caspase inhibitors to prevent cell death under these conditions. Moreover, adenovirus-mediated overexpression of p53 killed embryonic and postnatal neurons without activating caspases. Thus, p53-mediated neuronal cell death may occur via both caspase-dependent and caspase-independent pathways. These results demonstrate that p53 is required for caspase activation in response to some forms of neuronal injury. However, the relative importance of caspase activation in neurons depends on the developmental status of the cell and the specific nature of the death stimulus.

Product catalyzes the deamidation of D145N dehalogenase to produce the wild-type enzyme

Aspartate 145 plays an essential role in the active site of 4-chlorobenzoyl-CoA dehalogenase, forming a transient covalent link at the 4-position of the benzoate during the conversion of the substrate to 4-hydroxybenzoyl-CoA. Replacement of Asp 145 by residues such as alanine or serine results in total inactivation, and stable complexes can be formed with either substrate or product. The Raman spectroscopic characterization of some of the latter is described in the preceding publication (Dong et al.). The present work investigates complexes formed by D145N dehalogenase and substrate or product. Time-resolved absorption and Raman difference spectroscopic data show that these systems evolve rapidly with time. For the substrate complex, initially the absorption and Raman spectra show the signatures of the substrate bound in the active site of the asparagine 145 form of the enzyme but these signatures are accompanied by those for the ionized product. After several minutes these signatures disappear to be replaced with those closely resembling the un-ionized product in the active site of wild-type dehalogenase. Similarly, for the product complex, the absorption and Raman spectra initially show evidence for ionized product in the active site of D145N, but these are rapidly replaced by signatures closely resembling the un-ionized product bound to wild-type enzyme. It is proposed that product bound to the active site of asparagine 145 dehalogenase catalyzes the deamidation of the asparagine side chain to produce the wild-type aspartate 145. For the complexes involving substrate, the asparagine 145 enzyme population contains a small amount of the WT enzyme, formed by spontaneous deamidation, that produces product. In turn, these product molecules catalyze the deamidation of Asn 145 in the major enzyme population. Thus, conversions of substrate to product and of D145N to D145D dehalogenase go on simultaneously. The spontaneous deamidation of asparagine 145 has been characterized by allowing the enzyme to stand at RT in Hepes buffer at pH 7.5. Under these conditions deamidation occurs with a rate constant of 0.0024 h-1. The rate of product-catalyzed deamidation in Hepes buffer at 22 degrees C was measured by stopped-flow kinetics to be 0.024 s-1, 36000 times faster than the spontaneous process. A feature near 1570 cm-1 could be observed in the early Raman spectra of both substrate and product-enzyme complexes. This band is not associated with either substrate or product and is tentatively assigned to an ester-like species formed by the attack of the product's 4-O- group on the carbonyl of asparagine's side chain and the subsequent release of ammonia. A reaction scheme is proposed, incorporating these observations.

Modulating electron density in the bound product, 4-hydroxybenzoyl-CoA, by mutations in 4-chlorobenzoyl-CoA dehalogenase near the 4-hydroxy group

The enzyme 4-chlorobenzoyl-CoA dehalogenase hydrolyzes 4-chlorobenzoyl-CoA (4-CBA-CoA) to 4-hydroxybenzoyl-CoA (4-HBA-CoA). Biochemical and crystallographic studies have identified a critical role for the dehalogenase residue Asp 145 in close proximity to the ligand's 4-hydroxy group in the structure of the product-enzyme complex. In the present study the effects of site selective mutations at Asp 145 on the product complex are explored by Raman spectroscopy. The spectral signatures of the WT-product complex, the large red shift in lambdamax, and the complete reorganization of the benzoyl ring modes in Raman data are absent for the D145E complex. The major spectral perturbations in the WT complex are brought about by strong electron "pull" at the benzoyl carbonyl and electron "push" by the side chain of Asp 145 near the 4-OH group. Acting in concert, these factors polarize the benzoyl's pi-electrons. Since the Raman data show that very strong electron pull occurs at the benzoyl's carbonyl in the D145E complex, it is apparent that the needed electron push near the benzoyl's 4-OH group is missing. Thus, very precise positioning of Asp 145's side chain near the benzoyl's 4-position is needed to bring about the dramatic electron reorganization seen in the WT complex, and this criterion cannot be met by the glutamate side chain with its additional CH2 group. For two other Asp145 mutants D145A and D145S that lack catalytic activity, Raman difference spectroscopic data for product complexes demonstrate the presence of a population of ionized product (i.e., 4-O-) in the active sites. The presence of the ionized phenolate form explains the observation that these complexes have highly red-shifted absorbance maxima with lambdamaxs near 400 nm. For the WT complex only the 4-OH form is seen, ionization being energetically expensive with the presence of the proximal negative charge on the Asp 145 side chain. Semiquantitative estimates of the pKa for the bound product in D145S and D145A indicate that this ionization lies in the pH 6.5-7.0 range. This is approximately 2 pH units below the pKa for the free product. The Raman spectrum of 4-dimethylaminobenzoyl-CoA undergoes major changes upon binding to dehalogenase. The bound form has two features near 1562 and 1529 cm-1 and therefore closely resembles the spectrum of product bound to wild-type enzyme, which underlines the quinonoid nature in these complexes. The use of a newly developed Raman system allowed us to obtain normal (nonresonance) Raman data for the dehalogenase complexes in the 100-300 microM range and heralds an important advance in the application of Raman spectroscopy to dilute solutions of macromolecules.

Mechanisms of hypoxia-induced endothelial cell death. Role of p53 in apoptosis

Endothelial cell death may contribute to tissue injury from ischemia. Little is known, however, about the characteristics of endothelial cell death in response to hypoxia. Using an in vitro model, we found that human umbilical vein endothelial cells were resistant to hypoxia-induced cell death with only a 2% reduction in viability at 24 h and 45% reduction in viability at 48 h. Overexpression of a mutant, IkappaBalpha, via adenoviral vector did not potentiate cell death in hypoxia, indicating that nuclear factor-kappaB activation was not involved in cytoprotection. Cell death in hypoxia was determined to be apoptotic by 3' labeling of DNA using terminal deoxynucleotidyl transferase staining and reversibility of cell death with a caspase inhibitor. Exposure of endothelial cells to hypoxia did not alter levels of proapoptotic and antiapoptotic Bcl-2 family members Bax and Bcl-XL by immunoblot analysis. In contrast, changes in p53 protein levels correlated with the induction of apoptosis in hypoxic endothelial cells. Inhibition of the proteasome increased p53 protein levels and accelerated cell death in hypoxia. Overexpression of p53 by adenoviral transduction was sufficient to initiate apoptosis of normoxic endothelial cells. These data provide a framework for the study of factors regulating endothelial cell survival and death in hypoxia.

Back pain and agricultural work among farmers: an analysis of the Colorado Farm Family Health and Hazard Surveillance Survey

BACKGROUND

Back pain is the most prevalent occupational health problem experienced by much of the world's workforce. However, agricultural work-related back pain occurring among US farmers working on small operations or family farms is usually not included in surveillance. With data collected by Colorado Farm Family Health and Hazard Surveillance Survey, this study reports characteristics of and risk factors for back pain among adult farmers living in eight Colorado counties.

METHODS

A stratified probability sample of 500 farms was selected in proportion to the number of farms in study areas. During the 4-year period from 1993 through 1996, 458 farms were enrolled in the study and 759 farmers were interviewed using a questionnaire. Information on self-reported back pain and potential risk factors among 742 white farmers was evaluated and reported here.

RESULTS

A total of 194 farmers (26.2%) reported to have had at least one episode of back pain lasting for 1 week or more. Males had a slightly higher prevalence of back pain than females (28.6% vs. 22.5%) and the lower back was the predominantly affected part of body among both males and females. In 45.4% of males and 43.9% of females back pain was brought on by repeated activities. Males' activities at work were more likely to cause back pain while females' activities at home were more likely to cause back pain. Three factors were found to be significantly associated with back pain: being depressed (odds ratio (OR) = 3.68, 95% confidence interval (CI) = 2.23-6.09), farming/ranching as main activities (OR = 1.66, CI = 1.17-2.36), and worked in agriculture for 10 to 29 years (OR = 1.62, CI = 1.14-2.30).

CONCLUSIONS

Our analyses indicate that back pain is an occupational health problem among farmers on small operations or family farms and that back pain affected males and females differently. The finding of significant positive associations between depression, farming activities, and back pain warrants further attention.

Generation of enhancer trap lines in Arabidopsis and characterization of expression patterns in the inflorescence

Eleven thousand, three hundred and seventy enhancer/promoter trap lines in Arabidopsis were generated via T-DNA transformation utilizing the binary vector pD991 that contains a minimal promoter fused to the uidA reporter gene. Overall 31% of the lines generated exhibit a staining pattern in the inflorescence. Flanking DNA has been cloned from 15 lines exhibiting inflorescence staining patterns by either thermal asymmetric interlaced PCR (TAIL-PCR), inverse PCR (IPCR), or partial library construction. Seeds from these lines are available from the ABRC and NASC Arabidopsis stock centers and DNA pools are available from the ABRC.

Nonfatal agricultural injuries among Colorado older male farmers

OBJECTIVES

This study described characteristics and potential risk factors for nonfatal agricultural injuries among older male farmers age 60 years and older in Colorado.

METHODS

A telephone survey was conducted among 113 older male farmers between 1993 and 1995. Agricultural injuries and potential risk factors were evaluated.

RESULTS

A total of 27 injuries were sustained. The leading external cause of injuries was livestock, and most of the injuries affected lower and upper extremities of the body. Injured farmers were more likely to be persons who had gone deeply into debt or who were using prescription medications.

DISCUSSION

Older farmers are at risk of injuries. The study results support the need to consider physical limitations of aging in developing prevention programs in agriculture.

Evidence for involvement of Bax and p53, but not caspases, in radiation-induced cell death of cultured postnatal hippocampal neurons

Bax (a death-promoting member of the bcl-2 gene family), the tumor suppressor gene product p53, and the ICE/ced-3-related proteases (caspases) have all been implicated in programmed cell death in a wide variety of cell types. However, their roles in radiation-induced neuronal cell death are poorly understood. In order to further elucidate the molecular mechanisms underlying radiation-induced neuronal cell death, we have examined the ability of ionizing radiation to induce cell death in primary cultured hippocampal neurons obtained from wild-type, p53-deficient and Bax-deficient newborn mice. Survival in neuronal cultures derived from wild-type mice decreased in a dose-dependent manner 24 hr after a single 10 Gy to 30 Gy dose of ionizing radiation. In contrast, neuronal survival in irradiated cultures derived from p53-deficient or Bax-deficient mice was equivalent to that observed in control, nonirradiated cultures. Western blot analyses indicated that neuronal p53 protein levels increased after irradiation in wild-type cells. However, Bax protein levels did not change, indicating that other mechanisms exist for regulating Bax activity. Adenovirus-mediated overexpression of p53 also caused neuronal cell death without increasing Bax protein levels. Irradiation resulted in a significant induction in caspase activity, as measured by increased cleavage of fluorogenic caspase substrates. However, specific inhibitors of caspase activity (zVAD-fmk, zDEVD-fmk and BAF) failed to protect postnatal hippocampal neurons from radiation-induced cell death. Staurosporine (a potent inducer of apoptosis in many cell types) effectively induced neuronal cell death in wild-type, p53-deficient and Bax-deficient hippocampal neurons, indicating that all were competent to undergo programmed cell death. These results demonstrate that both p53 and Bax are necessary for radiation-induced cell death in postnatal cultured hippocampal neurons. The fact that cell death occurred despite caspase inhibition suggests that radiation-induced neuronal cell death may occur in a caspase-independent manner.

A new technique of screening gene mutation--fluorescent fingerprinting

A new technique called fluorescent fingerprinting (FF) was set up and used to screen and detect gene mutation from a large number of samples by using fluorescent labelled ddNTP and ABI-373A sequencer. By comparing the colour ladders of several lanes from the same sequencing region of different samples, any band with a different colour from its neighbours or a pattern displacement could be easily found out in the Macintosh screen which indicates a gene mutation. Then, the sequencing peak-chromatograms were made out only for the selected samples.

[Study on the epidemiological characteristics of diabetes mellitus and IGT in China]

A community-based survey on diabetes mellitus (DM) and impaired glucose tolerance (IGT) was carried out in 11 provinces/autonomous regions/municipalities of China from July 1995 to June 1997, using stratified cluster sampling method and diagnostic criteria recommended by WHO. A total number of 42,751 persons aged 20-74 years having lived in the communities longer than 5 years, were selected as research subjects. Results showed that the prevalence rates of DM and IGT standardized by age were 3.21% (95% CI: 3.05%-3.37%) and 4.76% (95% CI: 4.56%-4.96%) respectively; with a ratio of DM to IGT 1:1.5. The prevalence rates of DM and IGT increased parallelly with the increase of age. Among the 20-39 years old, the prevalence rates of DM and IGT were 1.01% and 2.70% respectively, while both of them exceeded 7% and 11% among people aged 50-59 years and above 60 years.

Studies on human fetal lens crystallins under oxidative stress and protective effects of tea polyphenols

PURPOSE

To investigate the oxidative modification of water-soluble crystallins of human fetal lens with H2O2 and fourteen metal ions with or without EDTA. Tea-polyphenols (TP) was added to above solutions in order to testing their antioxidative abilities.

METHODS

The experiments were performed at 37 degrees C with final concentration of 2.5 mg/ml protein, 0.1 mM metal ions, 0.3 mM EDTA and 1.0 mM H2O2. Then the TP was added to the solution with CuSO4 and H2O2, after 5 or 24 hours, the crystallins were analysed with SDS-PAGE and IEF.

RESULTS

There were marked oxidative modifications of lens protein in H2O2 and copper without EDTA. In SDS-PAGE patterns, we found an increase in those species above of bands higher than 30 kD and some diffuse bands from 30 to 17 kD after 5 hours. In IEF patterns, there were a general increase on acidity with loss of the more basic species. When the TP was added, there was not any difference with control group.

CONCLUSION

The results indicate that exposure of water-soluble protein to H2O2 and copper leads to covalent crosslinking and cleavage of polypeptides. After 24 hours, the development of the oxidative modifications of crystallins continues, comparison with the catalytic strength, copper ions stronger than the iron ions. On other hand, this work reported that the anti-oxidative action of TP is strong.

[The development of medical infusion monitoring and controlling network system]

The paper provided a medical infusion monitoring and controlling network system, in which the mainframe and its extensions can realize communication with each other by means of asynchronous serial port. At the same time, every extension can test infusion speed and adjust it to the presetting infusion speed gradually. The extensions also can alarm and stop infusion automatically when infusion will be over or there is a infusion malfunction.

Financing changes of schistosomiasis control programmes in China 1980-1995: a case study in Songzi county

To assess the financing changes of schistosomiasis control programmes in China and estimate the impact of these changes on patients' treatment-seeking behaviour and control of schistosomiasis, a survey was conducted in five schistosomiasis-endemic areas of the lake regions, Hubei province, in 1996. This paper reports financing changes and their impact on the incidence and prevalence of schistosomiasis from one of the five areas as a case study. By examining the surveillance and financial data from 1980 to 1995, and through focus group discussions we found that the schistosomiasis control programmes in People's Republic of China have gone through dramatic financing changes from 1980 to 1995, when the transitions of China's social, economic, and political systems happened. The proportions of funding to schistosomiasis control programmes from high level governmental agencies, county budgets, and services revenue changed from 60%, 23%, and 17%, respectively, in 1980-1987 to 0.7%, 22.3%, and 72% in 1995. The percentages of expenditure of schistosomiasis control activities, salaries and bonuses, and other activities unrelated to schistosomiasis control, were 53.5%, 14.4, and 17.2% in 1980. These percentages changed to 7.7%, 33.3%, and 53.3%, respectively, in 1995. The preponderant role of the state in organizing, financing, and delivery of the services was replaced with the new system which is more influenced by the market economy. The incidence and the prevalence of schistosomiasis in the study area have increased year by year from 1980 to 1990, although there has been a tendency to decrease after 1991 but not to the low pre1980 levels. The collapse of the community-based medical system in rural areas and the dramatic financing changes of schistosomiasis control programmes have created major difficulties for schistosomiasis control in China.