Increased lymphocyte DNA strand breaks in rubber workers

OBJECTIVE

To study the effect of occupational exposure to rubber processing, smoking, and alcohol drinking on lymphocyte DNA damage.

SUBJECTS AND METHODS

Of 371 employees (197 men and 174 women) from a rubber factory in Guangzhou, 281 were rubber processing workers from five production sections and 90 were managerial workers. Information on occupational exposure, smoking, and drinking was collected by interviews. Blood samples were taken in the morning by venipuncture. DNA damages were measured by the Comet assay. Possible DNA-protein crosslinks were broken down by proteinase K. Tail moment, measured by Komet 4.0 image analysis software, was the measure of DNA damage.

RESULTS

The rubber processing workers had larger tail moment than the managerial workers (Geometric mean, 95%CI) [1. 77microm (1.64-1.90) versus 1.52microm (1.36-1.71), P=0.04]. Both smoking [1.93microm (1.74-2.13) versus 1.59microm (1.47-1.71), P=0. 003] and alcohol drinking [2.21microm (1.87-2.62) versus 1.63microm (1.53-1.74), P<0.001] increased tail moment. Tail moment differed significantly among job categories (F=3.21, P=0.008), the largest was observed in mixers. In the non-smoking and non-drinking workers, rubber processing workers had larger tail moment than managerial workers after adjusting for age (P=0.033). General linear model analysis showed that after adjusting for each other, occupational exposure (P=0.027), smoking (P=0.012), and alcohol drinking (P=0. 013) was associated with larger tail moment, whereas age and gender had no effect.

CONCLUSIONS

Occupational exposure to rubber processing, smoking, and alcohol drinking can cause DNA damage.

Werner protein recruits DNA polymerase delta to the nucleolus

Werner syndrome is a Mendelian disorder of man that produces a number of manifestations resembling human aging. This disorder is caused by inactivation of the wrn gene, a member of the RecQ family of DNA helicases. The helicase and exonuclease activities of the Werner protein (WRN) suggest that it functions in DNA transactions, but the physiological function of WRN remains elusive. We present several lines of evidence that WRN interacts specifically with the p50 subunit of polymerase delta, the major DNA polymerase required for chromosomal DNA replication. P50, identified by yeast two-hybrid screening, interacts physically with the C terminus of WRN. Native WRN protein coimmunoprecipitates with p50 in a cellular fraction enriched in nucleolar proteins, and this immunocomplex also includes p125, the catalytic subunit of polymerase delta. In subcellular localization studies of cells transfected with WRN, p50 and p125 redistribute to the nucleolus and colocalize with WRN. These results suggest that one of the functions of WRN protein is to directly modify DNA replication via its interaction with p50 and abet dynamic relocalization of the DNA polymerase delta complexes within the nucleus.

[Studies on the chemical constituents of Kaempferia marginata]

AIM

To study the chemical constituents of the rhizomes of Kaempferia galanga L. (Zingiberaceae).

METHODS

Various chromatographic techniques were used to separate and purify. Their physico-chemical properties and spectral data were used to elucidate the structures.

RESULTS

Six compounds were isolated from the hexane extract of K. galanga. Their structures were identified as marginatol (1), 8 (14), 15-sanderacopimaradiene-1 alpha, 9 alpha-diol (2), 8 (14), 15-sanderacopimaradiene-1 alpha, 6 beta, 9 alpha-triol (3), germacrone (4), trans-ethyl p-methoxycinnamate (5) and n-pentadecane (6) on the basis of spectral data (IR, MS, 1H-1H, 13C-1H NMR, NOEs and HMBC).

CONCLUSION

Marginatol (1) is a new isopimarene diterpenoid and was elucidated as 8(14), 15-isopimaradiene-6 alpha-ol. Compounds 2, 3 and 4 were isolated for the first time from this plant.

Effect of human neuronal tau on denaturation and reactivation of rabbit muscle D-glyceraldehyde-3-phosphate dehydrogenase

Human neuronal tau-40 (htau-40) has been used to study denaturation and renaturation of rabbit muscle D-glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12). Inactivation of GAPDH incubated with tau was more distinguishably detected than that of control GAPDH during thermal and guanidine hydrochloride (GdnHCl) denaturation. However, tau did not influence the activity of GAPDH at room temperature or in solution without GdnHCl. A marked change in both the emission intensity and emission maximum of the intrinsic fluorescence at 335 nm of GAPDH with tau was observed when GdnHCl concentration was 0.8 M, but that of the control without tau occurred in 1.2 M GdnHCl. The first-order rate of the decrease in the fluorescence intensity of the enzyme with tau was approximately twice as great as that of GAPDH without tau. Kinetics of inactivation of GAPDH with tau in 0.2 M GdnHCl was a monophasic procedure, instead of the biphasic procedure followed by the control, as described before [He, Zhao, Yan and Li (1993) Biochim. Biophys. Acta 1163, 315-320]. Similar results were obtained when the enzyme was thermally denatured at 45 degrees C. It revealed that tau bound to the denatured GAPDH but not the native molecule. On the other hand, tau suppressed refolding and reactivation of GAPDH when this enzyme was reactivated by dilution of GdnHCl solution. Furthermore, tau improved the aggregation of the non-native GAPDH in solutions. It suggested that tau acted in an anti-chaperone-like manner towards GAPDH in vitro. However, tau lost that function when it was aggregated or phosphorylated by neuronal cdc2-like protein kinase. It showed that tau's anti-chaperone-like function depended on its native conformation.

Prostanoids mediate the protective effect of trefoil factor 3 in oxidant-induced intestinal epithelial cell injury: role of cyclooxygenase-2

Trefoil factors are small peptides found in several mammalian tissues including gut, respiratory tract and brain. Their physiological function is not well understood. Among them, trefoil factor 3 (intestinal trefoil factor) is known to be cytoprotective in the gut. However, the molecular mechanism and secondary mediators of trefoil factor 3 action are not known. In the present study, we examined whether the cyclooxygenase pathway is involved in trefoil factor 3 action. We showed that trefoil factor 3 significantly induces the production of prostaglandin E(2) and prostaglandin I(2) in IEC-18 cells (an intestinal epithelial cell line) in a dose dependent manner. Western blot and immunohistochemistry revealed that trefoil factor 3 (2.5 microM) up-regulates the expression of cyclooxygenase-2 but not cyclooxygenase-1 in IEC-18 cells. Treating cells with trefoil factor 3 (10 microM) significantly attenuated reactive oxygen species-induced IEC-18 cell injury. This effect is blocked by NS-398 (10 microM), a selective cyclooxygenase-2 inhibitor. Moreover, we demonstrated that exogenously administered carbacyclin (1 microM, a stable analogue of prostaglandin I(2)) and/or prostaglandin E(2) (1 microM) caused a significant reduction of reactive oxygen species-induced cell injury, mimicking the effect of trefoil factor 3. In summary, our results indicate that trefoil factor 3 activates cyclooxygenase-2 in intestinal epithelium to produce prostaglandin I(2) and prostaglandin E(2), which function as survival factors and mediate the cytoprotective action of trefoil factor 3 against oxidant injury.

Expression, immunolocalization and sperm-association of a protein derived from 24p3 gene in mouse epididymis

The cDNA sequence for 24p3 protein in ICR mouse epididymal tissue was determined by PCR using primers designed according to the cDNA sequence derived from 24p3 protein in mouse uterine tissue. In the present study, 24p3 protein was immunolocalized in the epithelial cells and lumen of mouse epididymis. Both immunoblot analysis for protein and northern blot analysis for mRNA level showed a declining gradient of 24p3 expression from the caput to caudal region of the epididymis. The 24p3 protein was undetectable in the testis. These findings suggest that the 24p3 protein is a caput-initiated secretory protein in the mouse epididymis. A postnatal study revealed that 24p3 gene expression occurred in mice at the age of 14 days, before the completion of epididymal differentiation. This expression remained at a constant level until epididymal differentiation was completed. We also found that the secreted 24p3 protein interacted predominantly with the acrosome of caudal spermatozoa. Our findings suggest that the epididymal 24p3 protein is a caput-initiated and sperm-associated gene product and may be important in the reproductive system.

[Wavelet packet-based ECG compression]

A wavelet packet-based algorithm for the compression of ECG is presented in the paper. The wavclet packet algorithm, which synthesizes the efficiency and the flexibility of the wavelet pacheket, generates significantly lower data rates with less computational effort.

Burst firing of action potentials in central snail neurons elicited by d-amphetamine: effect of anticonvulsants

The effect of anticonvulsants on the burst firing of action potentials in snail central neuron elicited by d-amphetamine was studied in the identified RP4 neuron of the African snail, Achatina fulica Ferussac. Oscillation of membrane potential and burst firing of action potentials were elicited by d-amphetamine in a concentration-dependent manner. Voltage clamped studies revealed that d-amphetamine elicited a negative slope resistance (NSR) in steady-state I-V curve between - 40 and - 10 mV. The burst firing of action potentials was alleviated following extracellular application of phenytoin, but was not affected after ethosuximide, carbamazepine, and valproic acid. The NSR elicited by d-amphetamine was blocked by phenytoin. However, the NSR was not altered if carbamazepine was added. These results suggest that of the four anticonvulsants tested, only phenytoin could alleviate the burst firing of action potentials elicited by d-amphetamine in snail neuron.

Ovarian steroidogenic responsiveness to exogenous gonadotropin stimulation in young and middle-aged female rats

Reproductive aging in the female rat is associated with gradual declines in LH secretion and ovarian progesterone (P) production. This study examined whether the influences of aging on P levels reflect decreased ovarian responsiveness to gonadotropin stimulation, as opposed to changes in gonadotropin release. Young and middle-aged regularly cyclic female rats received sodium pentobarbital to block endogenous proestrous luteinizing hormone (LH) surges, followed by administration of various doses of human chorionic gonadotropin (hCG). Similar treatments were performed in middle-aged acyclic persistent-estrous (PE) females. Injection of hCG resulted in equivalent plasma hCG levels in each treatment group. At the lowest hCG dose tested, a significant rise in plasma P levels was observed in middle-aged cyclic rats, but not in young cyclic or middle-aged PE females. This unexpected finding may reflect accelerated follicular development in middle-aged cyclic females, as suggested by a previous study. At the intermediate dose, young and middle-aged cyclic but not PE rats displayed significantly increased P in response to hCG. At the highest dose tested, all three groups of rats displayed increased P levels after hCG stimulation. However, P concentrations were significantly lower in middle-aged PE than regularly cyclic females. Northern and slot blot hybridization analyses revealed that ovarian mRNA levels for cytochrome P450 side-chain cleavage, the rate-limiting enzyme in P synthesis, were markedly reduced in PE rats following hCG stimulation. These findings indicate that ovarian responsiveness to gonadotropin stimulation is impaired in middle-aged PE, but not regularly cyclic rats, and suggest influences of cycle status on the biochemical and molecular mechanisms regulating ovarian steroid production. Furthermore, these findings reveal that attenuated P production in middle-aged proestrous rats is due to attenuated preovulatory LH surges, rather than decreased ovarian sensitivity to LH.

A CCAAT/enhancer-binding protein site within antioxidant/electrophile response element along with CREB-binding protein participate in the negative regulation of rat GST-Ya gene in vascular smooth muscle cells

Studies were conducted to evaluate the negative regulatory function of rat (r)GST-Ya antioxidant/electrophile response element (ARE/EpRE) in vascular smooth muscle cells (vSMCs). We report that CCAAT/enhancer-binding protein (C/EBP)-beta interacts with ARE/EpRE in the rGST-Ya promoter and that aryl hydrocarbon receptor (AhR) is present within the protein complex binding to the C/EBP site. Overexpression of C/EBP-beta or C/EBP-alpha repressed, whereas AhR enhanced, 1.6CAT reporter activity in cells treated with benzo(a)pyrene (BaP). Overexpression of CREB-binding protein (CBP) nullified repression of rGST-Ya transcription. Human adenovirus E1A protein abrogated cotransactivation by CBP but an E1A mutant did not. Overexpression of C/EBPs abrogated stimulation of 1.6CAT by CBP or AhR alone, or in combination, regardless of BaP treatment. Similar profiles were observed using an AhRECAT construct. The C/EBP site within the ARE/EpRE inhibited chemical inducibility of the AhRE. The pattern of mouse GST-Ya regulation by BaP was similar to that of rGST-Ya. We conclude that multiple mechanisms mediate negative regulation of GST-Ya gene in vSMCs, most significant of which are that C/EBP-beta inhibits AhRE or ARE/EpRE inducibility of GST-Ya, limiting CBP levels compromise gene induction, functional interference exists between AhRE and ARE/EpRE, and AhR alone, or in combination with C/EBP-beta, functions as a repressor of the ARE/EpRE.

Muscle regulatory factor gene: zebrafish (Danio rerio) myogenin cDNA

Myogenin is one of the basic helix-loop-helix proteins that regulate muscle-specific gene expression. Using reverse transciption-polymerase chain reaction (RT-PCR), 5'- and 3'-rapid amplification of cDNA ends (RACE), zebrafish myogenin cDNA was cloned from mRNA of embryos at 10-96 h post-fertilization. The cDNA, at 1384 base pairs (bp), contained a 771-bp open reading frame with 113- and 500-bp flanking regions at the 5'- and 3'-ends, respectively. The deduced amino acid sequences of zebrafish myogenin encoded a 256-amino-acid polypeptide. In a comparison with myogenin of carp, trout, Xenopus, chicken and human, zebrafish myogenin shared 90.9, 77.6, 70.3, 62.9 and 51.5% amino acid identity, respectively. The basic helix-loop-helix domains in myogenin are all conserved. The molecular phylogenic tree demonstrated that myogenin of zebrafish is more closely related to that of fish than to the myogenin of other vertebrates.

Semantic verbal fluency deficit as a familial trait marker in schizophrenia

This study examined neurocognitive deficits as familial vulnerability factors to schizophrenia. Twenty-three Chinese schizophrenic patients, 21 of their non-psychotic siblings and 26 healthy volunteers, matched for age, sex and education, were assessed by using a battery of neurocognitive tests including: Wisconsin Card Sorting Test (WCST), semantic verbal fluency, logical memory, digit span, information, comprehension and similarity. The results showed that siblings had significantly less word output in the verbal fluency test as compared to controls. No significant difference was found between siblings and controls for other tests except that a trend difference was noted for the performance on the similarity test and number of categories completed on the WCST. The verbal fluency abnormality can be considered as a familial trait marker for schizophrenia. Relationships between the residual symptoms after an acute psychotic episode and the magnitude of familial risk were examined. More severe residual symptoms of probands at clinical remission could be predicted by their older age of onset and by better verbal fluency performance in their non-psychotic siblings. This tentatively suggests that patients with a milder genetic form of schizophrenic illness may have a more severe environmental contribution to cerebral insult according to the multifactorial/threshold model. The environmental cerebral insult may cause structural abnormalities leading to incomplete remission of clinical symptoms.

Transcription factor NF-kappaB signals antianoikic function of trefoil factor 3 on intestinal epithelial cells

Transcription factor NF-kappaB has both pro-apoptotic and anti-apoptotic properties depending on the cell type. Its role in the intestinal epithelial cell has not been well elucidated. Trefoil factor 3 (TFF3) is an anti-apoptotic peptide secreted by intestinal goblet cells. Here we show that TFF3 activated NF-kappaB p50/p65 heterodimer within 1 h in IEC-18 cells (a nontransformed rat intestinal epithelial cell line). Moreover, we found that TFF3-treated IEC-18 cells are resistant to anoikis, an anchorage-related apoptosis in epithelium. In addition, the stable expression of a mutant form of the endogenous NF-kappaB inhibitor (IkappaBalpha(mut)) in IEC-18 cells results in a significant attenuation of anti-anoikic effect of TFF3. Taken together, these data indicate that (1) TFF3 is an endogenous gastrointestinal peptide with anti-anoikic property; (2) TFF3 activates NF-kappaB in enterocytes; and (3) TFF3-induced resistance to anoikis in intestinal epithelial cells is mediated by a distinct signaling cascade linked to NF-kappaB. Furthermore, our study implicates NF-kappaB as an important regulator in survival pathway of intestinal epithelial cells.

Induction of high levels of epitope-specific antibodies by epitope/peptide candidate vaccines against human immunodeficiency virus type-1 (HIV-1)

To test the immunogenicity of GPGRAFY-epitope-based candidate vaccines, a peptide with four repetitive GPGRAFY epitopes, V3-P1 [C-(GPGRAFY)4], and a peptide (PND) of the principal neutralizing domain (V3 loop: amino acid 301-328: C-TRPNNNTRKSIRIQRGPGRAFYTIGKI) on gp120 were synthesized and covalently coupled to a carrier protein BSA. Immunization of BALB/c mice and New Zealand White Rabbits with these conjugate vaccines engendered strong antibody responses against the PND (mouse serum titer by 1:12,800-25,600; rabbit serum titer by 1:6,400-12,800). Interestingly, the V3-P1-BSA conjugates and the PND-BSA conjugates could induce high levels of GPGRAFY-epitope-specific antibodies in the mice and rabbits (mouse serum titer by 1:25,600; rabbit serum titer by 1:12,800-25,600), while a recombinant gp160 subunit vaccine induced a low level of GPGRAFY-epitope-specific antibodies (serum titer by 1:400-1,600 in mice and rabbits). To confirm the above results, GPGRAFY-epitope-specific antibodies were isolated from rabbit sera induced by V3-P1-BSA, PND-BSA conjugates and rgp160 vaccine. In fact, 23-38 and 13-22 microg epitope-specific antibodies per milliliter serum were isolated from rabbit sera induced by V3-P1-BSA and PND-BSA conjugate, respectively, while 1.34 microg epitope-specific antibodies per milliliter serum were identified in rabbit serum induced by rgp160 vaccine. In the control group, only 0.069 microg proteins per milliliter serum were found in pooled pre-immune serum (normal serum). These results from mouse and rabbit experiments indicate that epitope and peptide vaccines both induce high levels of GPGRAFY-epitope-specific antibodies in comparison with rgp160 subunit vaccine, suggesting that epitope/peptide vaccines may be a new strategy to induce protective activity.

Fludarabine-based conditioning for allogeneic transplantation in adults with sickle cell disease

Although allogeneic transplantation can be curative for patients with sickle cell disease, the toxicity of conditioning regimens has precluded its use in adults with significant end-organ damage. Newer conditioning regimens have been developed that are less toxic and that may broaden the applicability of allogeneic transplantation in this disorder. We report two adults with end-stage sickle cell disease, who underwent allogeneic transplantation from an HLA-identical sibling donor after conditioning with fludarabine/melphalan and ATG. Both patients had been extensively transfused and one had multiple RBC antibodies. One of the patients also had end-stage renal disease, and was dialysis dependent. Engraftment occurred promptly in both patients. Both achieved 100% donor chimerism and both were free of pain crises after transplant. The first patient died of a respiratory failure related to chronic graft-versus-host disease (GVHD) on day 335 after transplantation. The second patient developed severe gastro-intestinal GVHD and TTP and died on day 147 after transplantation. Conditioning with fludarabine/melphalan and ATG followed by allogeneic stem cell transplantation resulted in prompt and reliable engraftment in adults with end-stage sickle cell disease. The incidence of severe GVHD was unacceptably high and may be related to the ethnicity of the patients or to the inflammatory state associated with pre-existing sickle cell disease.

Induction of monoclonal antibody with predefined ELNKWA epitope specificity by epitope vaccine

Since the hybridoma technique to produce monoclonal antibodies (MAbs) was discovered, thousands of MAbs with predefined protein specificity have been produced, and a natural or recombinant protein as antigen is necessary for inducing MAbs in the conventional hybridoma technique. To induce epitope-specific MAbs, we suggest an epitope vaccine as a new technique to induce MAbs with predefined epitope specificity. ELDKWA was identified as an important neutralizing epitope on HIV-1 gp41. The MAb 2F5, recognizing ELDKWA epitope, has shown broad neutralizing activity to many HIV strains, including primary isolates, but the mutant in ELNKWA epitope results in escape 2F5-based neutralization. To produce MAbs recognizing this mutated epitope for consideration of passive immunotherapy against the mutant bearing the ELNKWA epitope, MAbs with predefined ELNKWA epitope specificity were induced by synthetic epitope-peptide instead of a natural or recombinant gp41 bearing this epitope. Three MAbs were identified to recognize ELNKWA epitope on the synthetic epitope-peptide, and interestingly could bind the recombinant gp41 with ELDKWA epitope in an ELISA assay and immunoblotting analysis.

Identification of a novel platelet-derived growth factor-like gene, fallotein, in the human reproductive tract

We isolated the cDNA of a novel platelet-derived growth factor-like gene from human endometrium. The gene was named fallotein; it was 3007 bases in length, and encoded a protein of 345 amino acids. Antiserum against the fallotein protein can recognize a specific protein in the fallopian tube, with a molecular size in accordance with the anticipated size of fallotein. Fallotein mRNA is expressed in two molecular sizes, 3.8 and 2.9 kb, with the former being more abundant. High expression of the gene was found in the prostate, testis, and uterus. A weaker expression signal was found in the spleen, thymus, and small intestine, but expression of fallotein in the colon and peripheral blood leukocytes was negligible.

Distribution of voltage-gated sodium channel alpha-subunit and beta-subunit mRNAs in human hippocampal formation, cortex, and cerebellum

The distribution of mRNAs encoding voltage-gated sodium channel alpha subunits (I, II, III, and VI) and beta subunits (beta1 and beta2) was studied in selected regions of the human brain by Northern blot and in situ hybridisation experiments. Northern blot analysis showed that all regions studied exhibited heterogenous expression of sodium channel transcripts. In situ hybridisation experiments confirmed these findings and revealed a predominantly neuronal distribution. In the parahippocampal gyrus, subtypes II and VI and the beta-subunit mRNAs exhibited robust expression in the granule cells of the dentate gyrus and pyramidal cell layer of the hippocampus. Subtypes I and III showed moderate expression in granule cells and low expression in the pyramidal cell layer. Distinct expression patterns were also observed in the cortical layers of the middle frontal gyrus and in the entorhinal cortex. In particular, all subtypes exhibited higher levels of expression in cortical layers III, V, and VI compared with layers I and II. All subtypes were expressed in the granular layer of the cerebellum, whereas specific expression of subtypes I, VI, beta1, and beta2 mRNAs was observed in Purkinje cells. Subtypes I, VI, and beta1 mRNAs were expressed, at varying levels, in the pyramidal cells of the deep cerebellar nuclei. These data indicate that, as in rat, human brain sodium channel mRNAs have a distinct regional distribution, with individual cell types expressing different compliments of sodium channels. The differential distribution of sodium channel subtypes suggest that they have distinct roles that are likely to be of paramount importance in maintaining the functional heterogeneity of central nervous system neurons.

Prostanoids mediate the protective effect of trefoil factor 3 in oxidant-induced intestinal epithelial cell injury: role of cyclooxygenase-2

Trefoil factors are small peptides found in several mammalian tissues including gut, respiratory tract and brain. Their physiological function is not well understood. Among them, trefoil factor 3 (intestinal trefoil factor) is known to be cytoprotective in the gut. However, the molecular mechanism and secondary mediators of trefoil factor 3 action are not known. In the present study, we examined whether the cyclooxygenase pathway is involved in trefoil factor 3 action. We showed that trefoil factor 3 significantly induces the production of prostaglandin E(2) and prostaglandin I(2) in IEC-18 cells (an intestinal epithelial cell line) in a dose dependent manner. Western blot and immunohistochemistry revealed that trefoil factor 3 (2.5 microM) up-regulates the expression of cyclooxygenase-2 but not cyclooxygenase-1 in IEC-18 cells. Treating cells with trefoil factor 3 (10 microM) significantly attenuated reactive oxygen species-induced IEC-18 cell injury. This effect is blocked by NS-398 (10 microM), a selective cyclooxygenase-2 inhibitor. Moreover, we demonstrated that exogenously administered carbacyclin (1 microM, a stable analogue of prostaglandin I(2)) and/or prostaglandin E(2) (1 microM) caused a significant reduction of reactive oxygen species-induced cell injury, mimicking the effect of trefoil factor 3. In summary, our results indicate that trefoil factor 3 activates cyclooxygenase-2 in intestinal epithelium to produce prostaglandin I(2) and prostaglandin E(2), which function as survival factors and mediate the cytoprotective action of trefoil factor 3 against oxidant injury.

Humic acid-induced echinocyte transformation in human erythrocytes: characterization of morphological changes and determination of the mechanism underlying damage

Blackfoot disease (BFD) is a peripheral arterial occlusive disease found among human inhabitants along the southwest coast of Taiwan. Well water used for drinking and cooking contains humic acid (HA), which may be a possible etiological factor. In this study, HA toxicity was investigated in human erythrocytes and was found to induce echinocytic formation. Morphological changes occurred in both a concentration- and time-dependent fashion. The presence of HA was also observed to facilitate the loading of erythrocytes with excess Ca(2+) (1 mM), which may have occurred following permeability changes in cell membranes, leading to echinocytic transformations. Sodium dodecyl sulfate (SDS) gel electrophoresis indicated that echinocyte formation was due to the oxidation of normal membrane proteins that were replaced by high-molecular-weight proteins. Humic acid also induced hemoglobin oxidation in erythrocytes. Data show that oxidative stress generated by HA as well as direct effects were exerted on the cytoskeleton of erythrocytes, and these may be significant factors in the etiology of BFD.

Molecular cloning, characterization, and differential expression of a glucoamylase gene from the basidiomycetous fungus Lentinula edodes

The complete nucleotide sequence of putative glucoamylase gene gla1 from the basidiomycetous fungus Lentinula edodes strain L54 is reported. The coding region of the genomic glucoamylase sequence, which is preceded by eukaryotic promoter elements CAAT and TATA, spans 2,076 bp. The gla1 gene sequence codes for a putative polypeptide of 571 amino acids and is interrupted by seven introns. The open reading frame sequence of the gla1 gene shows strong homology with those of other fungal glucoamylase genes and encodes a protein with an N-terminal catalytic domain and a C-terminal starch-binding domain. The similarity between the Gla1 protein and other fungal glucoamylases is from 45 to 61%, with the region of highest conservation found in catalytic domains and starch-binding domains. We compared the kinetics of glucoamylase activity and levels of gene expression in L. edodes strain L54 grown on different carbon sources (glucose, starch, cellulose, and potato extract) and in various developmental stages (mycelium growth, primordium appearance, and fruiting body formation). Quantitative reverse transcription PCR utilizing pairs of primers specific for gla1 gene expression shows that expression of gla1 was induced by starch and increased during the process of fruiting body formation, which indicates that glucoamylases may play an important role in the morphogenesis of the basidiomycetous fungus.

Salvianolic acid B protects brain against injuries caused by ischemia-reperfusion in rats

AIM

To study the protective effects of salvianolic acid B (Sal B) against the ischemia-reperfusion induced rat brain injury.

METHODS

Focal cerebral ischemia-reperfusion model in rats was employed to study the protective effects of Sal B. The behavioural tests were used to evaluate the damage to the central nervous system. Spectrophotometric assay methods were used to measure the activity of superoxide dismutase (SOD), contents of reduced glutathione (GSH), malondialdehyde (MDA), adenosine 5-triphosphorate (ATP), and lactate acid (LA) in experimental rats' brain homogenate.

RESULTS

Focal cerebral ischemia-reperfusion resulted in abnormal behavior which could be alleviated by Sal B 10 mg.kg-1 i.v., and nimodipine (Nim) 4 mg.kg-1 i.p. At the same time, Sal B 10 mg.kg-1 and Nim 4 mg.kg-1 could inhibit the decrease in SOD, GSH, and ATP levels and the increase in MDA and LA levels caused by ischemia-reperfusion in brain.

CONCLUSION

Sal B showed a protective action against the ischemia-reperfusion induced injury in rat brain by reducing lipid peroxides, scavenging free radicals and improving the energy metabolism.

Multiepitope vaccines intensively increased levels of antibodies recognizing three neutralizing epitopes on human immunodeficiency virus-1 envelope protein

A few neutralizing antibodies against human immunodeficiency virus-1 (HIV-1) envelope proteins have been shown to be highly effective at neutralizing different strains in vitro, and exist at very low levels in the sera of HIV-1-infected individuals. Based on our hypothesis that epitope vaccination may be a novel strategy for inducing high levels of antibodies against HIV-1, we prepared multiepitope vaccines using three neutralizing epitopes (GPGRAFY, ELDKWA and RILAVERYLKD) on HIV-1 envelope proteins. The PI [C-G-(ELDKWA-GPGRAFY)2-K] and PII (CG-GPGRAFY-G-ELDKWA-G-RILAVERYLKD) peptides were synthesized and conjugated to a carrier protein, bovine serum albumin (BSA). After vaccination, both the PI-BSA and PII-BSA multiepitope vaccines induced high levels of epitope-specific antibodies to the three neutralizing epitopes (antibody titre: 1 : 12,800-102,400). The recombinant glycoprotein 160 (rgp160) subunit vaccine induced strong antibody responses to rgp160, but only very weak epitope-specific antibody responses to the three epitopes. The epitope-specific antibodies were isolated from rabbit sera by single epitope-peptide-conjugated sepharose columns. A yield of 51 microg of epitope-specific antibodies/ml of serum (mean value) was obtained and identified to recognize these epitopes, while 0.35 microg of protein was isolated from 1 ml of pooled preserum by C-(ELDKWAG)4- or C-(RILAVERYLKD-G)2-K- and C-(GPGRAFY)4-sepharose columns. The levels of these epitope-specific antibodies induced in rabbits were much greater than 1 microg/ml, a level that is considered to confer long-term protection against some viruses. Moreover, these antibodies recognized the neutralizing epitopes on peptides and rgp41. Based on the fact that a very low level of ELDKWA epitope-specific antibodies exist in HIV-1-infected individuals, these results suggesting that synthetic epitope vaccines could induce high levels of multiepitope-specific neutralizing antibodies indicate a new strategy for developing an effective neutralizing antibody-based epitope/peptide vaccine against HIV-1.

Haematological and spermatotoxic effects of ethylene glycol monomethyl ether in copper clad laminate factories

OBJECTIVES

To investigate the effects of ethylene glycol monomethyl ether (EGME) on haematology and reproduction in exposed workers.

METHODS

53 Impregnation workers from two factories that make copper clad laminate with EGME as a solvent were recruited as the exposed group. Another group of 121 lamination workers with indirect exposure to EGME was recruited as the control group. Environmental monitoring of concentrations of EGME in air and biological monitoring of urinary methoxyacetic acid (MAA) concentrations were performed. Venous blood was collected for routine and biochemical analyses. Semen was collected from 14 workers exposed to EGME for sperm analysis and was compared with 13 control workers.

RESULTS

Results of haematological examination showed that the haemoglobin, packed cell volume, and red blood cell count in the male workers exposed to EGME were significantly lower than in the controls. The frequency of anaemia in the exposed group (26.1%) was significantly higher than in the control group (3.2%). However, no differences were found between the female workers exposed and not exposed to EGME. After adjustment for sex, body mass index, and duration of employment, red blood cell count was significantly negatively associated with air concentrations of EGME, and haemoglobin, packed cell volume, and red blood cell count were significantly negatively associated with urinary concentrations of MAA. The pH of semen in the exposed workers was significantly lower than in the control workers, but there were no significant differences in the sperm count or sperm morphology between the exposed and control groups.

CONCLUSION

It can be concluded that EGME is a haematological toxin, which leads to anaemia in the exposed workers. However, the data from this study did not support the theory of a spermatotoxic effect of EGME.

WRN or telomerase constructs reverse 4-nitroquinoline 1-oxide sensitivity in transformed Werner syndrome fibroblasts

WRN encodes a RecQ helicase, which is mutated in Werner syndrome. Werner syndrome is a genetic condition of young adults characterized by premature aging, limited replicative capacity of cells in vitro, and increased cancer risk. Telomerase is a reverse transcriptase that extends the G-rich strand of telomeric DNA. Primary cells in vitro typically lack telomerase activity and undergo senescence, whereas telomerase is reactivated in many, but not all, tumors. The roles of the two genes are not known to be related. Here we report the development of an effective colony-forming assay in which a SV40-transformed Werner fibroblast cell line is 6-18-fold more sensitive to 4-nitroquinoline 1-oxide than SV40-transformed normal cell lines. The sensitivity can be partially reversed by transfecting a normal WRN gene but not a mutated WRN gene into the cells. Curiously, the sensitivity can be reversed equally well by transfecting a telomerase gene (TERT) into the cells. These data indicate the possibility of an interdependent function of these two genes.