[Bone mineral density and exercises: a cross-sectional study on Chinese athletes]

OBJECTIVES

To evaluate the effect of exercise to osteoporosis by bone mineral density (BMD) measurement of athelets comparing normal individuals in general population.

METHODS

BMD of radium, lumber spine, and femoral neck were measured by single photon absorptiometry (SPA), quantitative CT (QCT), and dual X-ray absorptiometry (DXA) respectively in athletes (n = 162, male 79, female 83) and age matched non-athletes normal population (n = 204, male 91, female 113) in Beijing.

RESULTS

BMD of all sites in all age groups of both male and female athletes are significantly higher comparing with that in non-athletic population. This predominance in athletes is even more distinctive in peak bone mass. Peak bone mass of male athletes is significantly higher than that of female athletes. Bone loss with age is less apparent in athletes than in control. However, there is an accelerated decline of BMD in lumber spine and femoral neck in 30-39 year age group in both male and female athletes, which may be due to the wanting of physical exercise.

CONCLUSIONS

Long term regular proper exercise started in adolescence may play a very important role in the prevention of osteoporosis by improving peak bone mass and decreasing bone loss.

Comparative polymerase chain reaction analysis of c-myc amplification on archival breast fine-needle aspiration materials

The oncogene c-myc is a key regulator of cell cycle progression (from G1 to S phase). The amplification of c-myc can either induce cell proliferation or apoptosis. As a part of our ongoing effort to develop methods for multiple tumor marker analysis, this study was carried out to determine whether biomarkers such as c-myc amplification could be analyzed on genetic materials collected from archival fine-needle aspiration (FNA) smears. A novel comparative PCR analysis was used to analyze c-myc amplification semiquantitatively. Genomic DNA was prepared using cells obtained from archival FNA materials that had undergone quantitative fluorescence image analysis (QFIA) for other biomarkers. Of the 72 cases selected from 1995 for this study, 53 had an adequate amount of DNA for analysis. A novel comparative PCR analysis was used to analyze c-myc amplification quantitatively. For each batch of experiments, DNA from the high c-myc expressing cells, HL-60, and DNA from the low expressing cells, K562, were served as positive and negative controls, respectively. c-myc amplification was observed in 16 (94.1%) of 17 malignant lesions, 5 (41.7%) of 12 proliferative breast diseases with nuclear atypia, and 4 (16.7%) of 24 other benign lesions (fibroadenoma or fibrocystic disease). The overall difference of c-myc expression among these groups was highly significant by chi2 analysis (P = 0.0002). We conclude that multiple phenotypic markers and genotypic markers may be combined in a risk assessment biomarker profile on small FNA samples that can be obtained on multiple occasions relatively noninvasively from the patient. The results of this study suggest that c-myc amplification may be a biomarker of breast cancer risk. However, additional large, prospective studies are needed to confirm the current observation.

Esophagogastric junction pressure topography after fundoplication

OBJECTIVES

This study compared the pressure topography after laparoscopic Nissen fundoplication to that of normal subjects and patients with hiatal hernia and reflux disease.

METHODS

Seven patients with fundoplication, 7 normal subjects and 7 patients with hiatal hernia, were studied. The squamocolumnar junction and intragastric margin of the esophagogastric junction (EGJ) were marked with metal clips. Axial and radial characteristics of EGJ pressure were mapped relative to the hernia and clipped during concurrent fluoroscopy and manometry. Responses to inspiration and abdominal compression were also analyzed.

RESULTS

Fundoplication modifies the EGJ by restoration of the hiatal component of EGJ pressure and elongation of the subdiaphragmatic component. Maximal EGJ pressure after fundoplication is mainly dependent on the extrinsic effect of the hiatal canal that compresses the esophagus; the resultant length of the EGJ reflects the length of the fundic wrap. Integrity of the EGJ after fundoplication is independent of the intrinsic lower esophageal sphincter itself.

CONCLUSIONS

Fundoplication alters the pressure topography of the EGJ by reducing the hiatal hernia, tightening the hiatal orifice, and constructing a subdiaphragmatic wrap of variable length. Each effect depends on different technical aspects of the surgery with the potential of substantial variability in the resultant pressure topography.

Delta9-THC training dose as a determinant for (R)-methanandamide generalization in rats: a systematic replication

Järbe et al. (1998a) trained rats to discriminate between (-)-delta9-tetrahydrocannabinol (delta9-THC) and vehicle, using different training doses in order to create assays with different efficacy demands, to examine whether (R)-methanandamide, an analog of the endogenous ligand anandamide, had lower efficacy than delta9-THC. Rats were initially trained with 3 mg/kg delta9-THC, then tested with (R)-methanandamide and delta9-THC. Thereafter, the rats were split into two groups and retrained with either 1.8 or 5.6 mg/kg delta9-THC, followed by additional tests with the two agonists. The current study systematically replicated this study in two groups of rats, trained from the outset to discriminate between vehicle and either 1.8 or 5.6 mg/kg delta9-THC, respectively. Two-lever operant drug discrimination procedures were used. The outcomes in the two studies were similar. In tests with (R)-methanandamide, full substitution occurred in the low-dose delta9-THC training group, whereas substitution was partial in the high-dose delta9-THC training group. (R)-Methanandamide in higher doses exerted marked suppression of lever pressing. In tests with delta9-THC, full substitution occurred in both delta9-THC-trained groups, and rates of responding were comparable to those observed during regular drug training sessions. In conclusion, both sets of data indicate that cannabinoid agonists either can have varying degrees of efficacy at a receptor site, or may produce their behavioral actions through multiple mechanisms, or both. Prevailing training-dose condition rather than prior training-dose history is the major determinant for the substitution pattern.

Temperature-dependent pharmacokinetics and pharmacodynamics of vecuronium

BACKGROUND

The authors evaluated the influence of temperature on the pharmacokinetics and pharmacodynamics of vecuronium because mild core hypothermia doubles its duration of action.

METHODS

Anesthesia was induced with alfentanil and propofol and maintained with nitrous oxide and isoflurane in 12 healthy volunteers. Train-of-four stimuli were applied to the ulnar nerve, and the mechanical response of the adductor pollicis was measured. Volunteers were actively cooled or warmed until their distal esophageal temperatures were in one of four ranges: < 35.0 degrees C, 35.0-35.9 degrees C, 36.0-36.9 degrees C, and > or = 37.0 degrees C. With temperature stabilized, vecuronium was infused at 5 microg x kg(-1) x min(-1) until the first response of each train-of-four had decreased by 70%. Arterial blood (for vecuronium analysis) was sampled at intervals until the first response recovered to at least 90% of its prevecuronium level. Vecuronium, 20 microg x kg(-1) x min(-1), was then infused for 10 min, and arterial blood was sampled at intervals for up to 7 h. Population-based nonlinear mixed-effects modeling was used to examine the effect of physical characteristics and core temperature on vecuronium pharmacokinetics and pharmacodynamics.

RESULTS

Decreasing core temperature over 38.0-34.0 degrees C decreases the plasma clearance of vecuronium (11.3% per degrees C), decreases the rate constant for drug equilibration between plasma and effect site (0.023 min(-1) per degrees C), and increases the slope of the concentration-response relationship (0.43 per degrees C).

CONCLUSIONS

Our results show that reduced clearance and rate of effect site equilibration explain the increased duration of action of vecuronium with reducing core temperature. Tissue sensitivity to vecuronium is not influenced by core temperature.

Measurement of ultrasonic power and electro-acoustic efficiency of high power transducers

In this paper, an improved method for the measurement of acoustic power and electro-acoustic efficiency of high power ultrasonic transducers is presented. The measuring principle is described, the experimental results are given. In comparison with traditional methods, the method presented in this paper has the advantages of simplicity, economy and practicality. The most important is that it can measure the output acoustic power and the electro-acoustic efficiency of the transducer under the condition of high power and practical applications, such as ultrasonic cleaning and soldering.

A multiple locus analysis of the collaborative study on the genetics of alcoholism data set

Parametric and nonparametric statistical methods have been applied to the alcohol dependence data set collected in the Collaborative Study on the Genetics of Alcoholism (COGA). Our nonparametric linkage analyses (NPL) were based on the S(all) statistic of GENEHUNTER [Kruglyak et al., 1996] and the improved NPL statistic of GENEHUNTER-PLUS [Kong and Cox, 1997]. Based on likely regions for alcohol susceptibility genes identified from our nonparametric analyses, we reanalyzed the data using several two-locus models. We used the TMLINK program [Lathrop and Ott, 1990] in the LINKAGE package for these parametric analyses.

Synthesis and structure-activity relationships of new second-generation taxoids

A series of second-generation taxoids bearing a substituent on the C-2-benzoyl group and modifications at C-3'/C-10 positions was synthesized. These taxoids exhibited 2-3 orders of magnitude higher potency than that of paclitaxel against drug-resistant human breast cancer cell lines. It is also noteworthy that three taxoids showed almost no difference in activity against drug-resistant and drug-sensitive cell lines, which are categorized as "advanced second generation taxoids".

Human acyl-CoA:cholesterol acyltransferase-1 is a homotetrameric enzyme in intact cells and in vitro

Acyl-CoA:cholesterol acyltransferase (ACAT) is a key enzyme in cellular cholesterol homeostasis and in atherosclerosis. ACAT-1 may function as an allosteric enzyme. We took a multifaceted approach to investigate the subunit composition of ACAT-1. When ACAT-1 with two different tags were co-expressed in the same Chinese hamster ovary cells, antibody specific to one tag caused co-immunoprecipitation of both types of ACAT-1 proteins. Radioimmunoprecipitations of cells expressing the untagged ACAT-1 or the 6-histidine-tagged ACAT-1 yielded a single radiolabeled band of predicted size on SDS-polyacrylamide gel electrophoresis. These results show that ACAT-1 exists as homo-oligomers in intact Chinese hamster ovary cells. We solubilized HisACAT-1 with the detergent deoxycholate or CHAPS (3-[(3-cholamidopropyl)-dimethylammonio]-1-propanesulfonic acid), performed gel filtration chromatography and sucrose density gradient centrifugations in H(2)O and D(2)O, and determined the Stokes radii and sedimentation coefficients of the HisACAT1-detergent complexes. The estimated molecular mass of HisACAT-1 is 263 kDa, which is 4 times that of the HisACAT-1 monomer (69 kDa). Finally, cross-linking experiments in intact cells and in vitro show that the increase in cross-linker concentrations causes an increase in size of the HisACAT-1-positive signals, forming material(s) 4 times the size of the monomer, supporting the conclusion that ACAT-1 is a homotetrameric enzyme.

Studies of the DXS7 polymorphism at the MAO loci in unipolar depression

From the fact that DXS7 polymorphism is closely related to monoamine oxidase (MAO) genes and MAO inhibitors are widely used in the treatment of unipolar depression, it is of particular interest to study the relationship between the DXS7 polymorphism and unipolar depression. Thus, this study examined the possible association between DXS7 polymorphism and unipolar depression in 66 cases versus 85 controls from Shanghai. Polymerase chain reaction and amplification fragment length polymorphism techniques were used for genotyping of the DXS7 locus in this study. Four alleles at the DXS7 locus were detected with length generated by polymerase chain reaction amplification ranging from 157 to 167 bp. Comparison of allele frequency in the DXS7 locus showed no difference between unipolar depression cases and normal controls in the total population set. When subclassified by age, a significant difference of allele frequency distribution was observed between early onset (before age 40) and late onset (after age 40) patients. The frequency of the 157-bp allele was decreased, whereas the frequency of the 165 allele was increased in late onset patients (0.3810 for the 157-bp allele and 0.5238 for the 165-bp allele) compared with that of early onset patients (0.6304 for the 157-bp allele and 0. 3261 for the 165-bp allele). There was also a difference of allele frequency between patients and normal controls with age over 40 years. The frequency of 165-bp allele increased significantly in late onset patients (0.5238) compared with that of controls within the same age range (0.3454). Association studies suggested that in the population with age over 40 years, presence of the 165-bp allele of DXS7 locus was significantly associated with unipolar depression (relative risk = 2.08, P < 0.05), whereas in the total population set, this association did not exist. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 88:598-600, 1999.

Messenger RNA expressions of vasopressin system and aquaporin-2 in adriamycin-induced nephrotic rats and effects of astragalus membranaceus

OBJECTIVE

To investigate the expressions of hypothalamic arginine vasopressin (AVP) mRNA, renal AVP V2 receptor mRNA, and AVP-dependent aquaporin-2 (AQP2) mRNA in rats with adriamycin-induced nephrotic syndrome. Effects of Chinese herb Astragalus membranaceus (AM) were also tested.

METHODS

Sprague-Dawley rats with four weeks of adriamycin-induced nephrotic syndrome (NS) were used in this study. Another group NS + AM was set to testify the effects of AM given 0.5 g/kg daily on NS. Hypothalamic AVP mRNA expression was examined by dot blot method. Reverse transcription polymerase chain reaction was applied for detection of renal cortical and medullary V2 receptor and AQP2 mRNA. The results were normalized by mRNA of glyceraldehyde-3-phosphate dehydrogenase from the same sample.

RESULTS

All rats receiving adriamycin presented typical nephrosis. No obvious difference in plasma osmolality was detected among NS, NS + AM, and normal control (NC) rats. Hypothalamic AVP mRNA expression was higher in NS rats than NC (53.59 +/- 5.49 vs 25.72 +/- 1.96, P < 0.01). AM completely reversed this up-regulated expression (21.88 +/- 1.25). In both cortex and medulla of the kidney, nephrotic rat had increased AVP V2 expressions by 169% and 55%, respectively, compared with normal control rat. The increment of expression of AQP2 mRNA was consistent with that of V2 receptor in NS rat. AM could partially however significantly correct these up-regulations of V2 and AQP2 mRNA expressions (P < 0.01).

CONCLUSION

The up-regulated mRNA expressions of hypothalamic AVP, renal V2 receptor and AQP2 might play a role in edema formation in adriamycin-induced nephrotic rats. AM exerts its therapeutical effects on nephrosis partially through this mechanism.

[Activated T lymphocytes in epiretinal membranes from eyes of patients with proliferative diabetic retinopathy]

PURPOSE

To investigate the potential contribution of immune-mediated processes to the development of proliferative diabetic retinopathy(PDR), an immunohistochemical study was undertaken to characterize the infiltrating immune cells in epiretinal membrances from the eyes of patients with PDR.

METHODS

A total of 15 PDR epiretinal membrane specimens obtained surgically from pars plans vitrectomy were studied by using a panel of monoclonal antibodies against T lymphocytes (CD4), interleukin-2(IL-2) and interleukin-2 recpetors(IL-2R).

RESULTS

Twelve of 15 specimens (80%) contained CD4-positive cells. IL-2 was found in 12 of 15 samples (80%), of which 11 also contained CD4-positive cells, and IL-2R was detected in 10 of 15 membranes(67%), of which 9 contained CD4-positive cells and released IL-2. Most of the IL-2R-positive membranes were from type I diabetic patients, 40% of them are younger than 40 years.

CONCLUSION

Our study demonstrated the involvement of activated immune cells and release of lymphokine(s) in more than half of the diabetic epiretinal membranes tested and revealed that the processes of immune responses and the biological effects of lymphokines(s) may play an important part in the development of epiretinal membranes of PDR, especially in young-onset and type I diabetes.

[Genetic association between mood disorder and monoamine oxidase gene]

OBJECTIVE

To ascertain whether the mood disorder (bipolar and unipolar) is genetically associated with genes polymorphisms of MAOA type and MAOB type in the Chinese.

METHODS

One hundred and thirty-two cases of Chinese with mood disorder were genotyped for the MAOA(CA)n, MAOB(GT)n and MAOB(TG)n locus using Amp-FLP.

RESULTS

Among 132 cases with mood disorder, 8 alleles (size: 112-126 bp) of MAOA(CA)n, 12 alleles (size: 168-198 bp) of MOAB(GT)n and 9 alleles (size: 195-213 bp) of MAOB(TG)n locus were observed. Comparison of the polymorphisms of all alleles in the three locus showed that no significant difference (P > 0.05) was seen in the frequency distribution between cases with mood disorder (bipolar and unipolar) and controls, but the frequency of 180 bp allele for MAOB(GT)n and 250 bp allele for MAOB(TG)n was significantly different (P < 0.05) between the two groups.

CONCLUSION

MAO gene (type A and B) is not associated with mood disorder in the Chinese.

Alpha-galactose based neoglycopeptides. Inhibition of verotoxin binding to globotriosylceramide

Solution and solid phase strategies for the synthesis of alpha-galactose based neoglycopeptide derivatives 2-13 were developed. Neoglycopeptides generated were tested for the inhibition of verotoxin binding to globotriosylceramide (Gb3) using ELISA. Among all of the compounds tested, only the lipid derivatives of neoglycopeptides, 11, 12 and 13 were found to be inhibitors, IC50 = 2.0 mM (11b and 12c) and 0.2 mM (11c and 13c). All of the inhibitors (11b, 11c, 12c and 13c) have a similar branching of the two alpha-galactosyl units at the N-terminal glycine residue of a short peptide and a lipid moiety attached at the C-terminal site. Both of these factors seem to be crucial for the inhibition. It is interesting to note that the inhibitors have only a portion of the natural trisaccharide ligand. The secondary groups either may contribute in sub-site oriented interactions with the protein receptors or may mimic the internal sugar units of the cell-surface ligand, Gb3.

Suppression of activin-induced apoptosis by novel antisense strategy in human prostate cancer cells

Apoptosin, a novel gene encoding a mitotic kinase-motif protein, is stimulated by activin, a member of TGF-beta family, in human LNCaP prostate cancer cells and in patient tissues. We employed a gene knockout methodology based on the covalent bonding of chemically modified antisense probes to apoptosin mRNAs in LNCaP cells. The mRNA-antisense hybrid duplexes were neither translated nor post-transcriptionally modified, resulting in no protein synthesis. Introducing antisense apoptosin into activin-induced apoptotic LNCaP cells prevented apoptosis, interfered with genomic DNA fragmentation and released cell cycle checkpoint. These findings suggest that the apoptosin, in addition to p53, is important in apoptotic regulation of human prostate cancers.

Picosecond transient absorption spectroscopy in the blue spectral region of photosystem I

Picosecond transient absorption difference spectroscopy in the blue wavelength region (380-500 nm) was used to study the early electron acceptors in photosystem I. Samples were photosystem I core particles with about 100 chlorophylls per reaction center isolated from the cyanobacterium Synechocystis sp. PCC 6803. After excitation at 590 nm at room temperature, decay-associated spectra (DAS) were determined from global analysis in the blue region, yielding two transient components and one nondecaying component. A 3 ps decay phase is interpreted as primarily due to antenna excited-state redistribution. A 28 ps decay phase is interpreted as due to overall excited-state decay by electron transfer. The nondecaying component is ascribed to the difference spectrum of P(700) and the quinone or A(1) electron acceptor (P(700)(+)A(1)(-) - P(700)A(1)). Decay curves on the millisecond time scale at different wavelengths were measured with an autoxidizable artificial electron acceptor, benzyl viologen, and the (P(700)(+) - P(700)) difference spectrum was constructed. The (A(1)(-) - A(1)) difference spectrum was obtained by taking the difference between the above two difference spectra. A parallel picosecond experiment under strongly reducing conditions was also done as a control experiment. These conditions stabilize the electron on an earlier acceptor, A(0). The nondecaying component of the DAS at low potential was assigned to (P(700)(+)A(0)(-) - P(700)A(0)) since the electron-transfer pathway from A(0) to A(1) was blocked. The [(P(700)(+)A(0)(-) - P(700)A(0)) - (P(700)(+) - P(700))] subtraction gives a spectrum, interpreted as the (A(0)(-) - A(0)) difference spectrum of a chlorophyll a molecule, consistent with previous studies. The (A(1)(-) - A(1)) spectrum resolved on the picosecond time scale shows significant differences with similar spectra measured on longer time scales. These differences may be due to electrochromic effects and spectral evolution.

Endothelin antagonists: substituted mesitylcarboxamides with high potency and selectivity for ET(A) receptors

We have previously disclosed the discovery of 2,4-disubstituted anilinothiophenesulfonamides with potent ET(A)-selective endothelin receptor antagonism and the subsequent identification of sitaxsentan (TBC11251, 1) as a clinical development compound (Wu et al. J. Med. Chem. 1997, 40, 1682 and 1690). The orally active 1 has demonstrated efficacy in a phase II clinical trial of congestive heart failure (Givertz et al. Circulation 1998, 98, Abstr. #3044) and was active in rat models of myocardial infarction (Podesser et al. Circulation 1998, 98, Abstr. #2896) and acute hypoxia-induced pulmonary hypertension (Chen et al. FASEB J. 1996, 10 (3), A104). We now report that an additional substituent at the 6-position of the anilino ring further increases the potency of this series of compounds. It was also found that a wide range of functionalities at the 3-position of the 2,4,6-trisubstituted ring increased ET(A) selectivity by approximately 10-fold while maintaining in vitro potency, therefore rendering the compounds amenable to fine-tuning of pharmacological and toxicological profiles with enhanced selectivity. The optimal compound in this series was found to be TBC2576 (7u), which has approximately 10-fold higher ET(A) binding affinity than 1, high ET(A)/ET(B) selectivity, and a serum half-life of 7.3 h in rats, as well as in vivo activity.

Cytokine receptor common beta chain as a potential activator of cytokine withdrawal-induced apoptosis

Growth factors and cytokines play an important role in supporting cellular viability of various tissues during development due to their ability to suppress the default cell death program in each cell type. To date, neither the triggering molecule nor the transduction pathway of these default apoptosis programs is understood. In this study, we explored the possibility that cytokine receptors are involved in modulating cytokine withdrawal-induced apoptosis (CWIA) in hematopoietic cells. Expression of the exogenous cytokine receptor common beta chain (betac), but not the alpha chains, accelerated CWIA in multiple cytokine-dependent cell lines. Reduction of the expression level of endogenous betac by antisense transcripts resulted in prolonged survival during cytokine deprivation, suggesting a critical role of betac in modulating CWIA. Fine mapping of the betac subunit revealed that a membrane-proximal cytoplasmic sequence, designated the death enhancement region (DER), was critical to the death acceleration effect of betac. Furthermore, DER accelerated cell death either as a chimeric membrane protein or as a cytosolic protein, suggesting that DER functions independently of the cytokine receptor and membrane anchorage. Cross-linking of the chimeric membrane-bound DER molecules by antibody or of the FK506-binding protein-DER fusion protein by a synthetic dimerizing agent, AP1510, did not abrogate the death acceleration effect. Transient transfection assays further indicated that DER promoted cell death in the absence of serum in the nonhematopoietic 293 cell line. In summary, our data suggest that betac plays an important role in modulating CWIA via an anchorage-independent and aggregation-insensitive mechanism. These findings may facilitate further studies on the signaling pathways of CWIA.

Using affinity capillary electrophoresis to evaluate average binding constant of 18-mer diphosphotyrosine peptide to antiphosphotyrosine Fab

We used affinity electrophoresis in capillaries to investigate the interaction between a monovalent antiphosphotyrosine antibody fragment, antigen-binding fragment (Fab), and a divalent antigen (dAg), an 18-mer diphosphopeptide phosphorylated on two-site tyrosine residues. The migration shift behavior of Fab in electrophoretic solution was observed and the quantitative expression was presented to estimate the arithmetical average value of the intrinsic affinities for two epitopes on the dAg with the Ag binding site on the Fab. In dAg excess, based on measurement of mobility changes of Fab analytes at different dAg concentrations, the experimental average dissociation constant (Kd = 27.7 microM) was calculated. It was also found that the structural variation of the two epitopes for binding specificity to the Ag-binding domain of Fab is not apparent. Moreover, the Kd values of Fab-dAg complexes were measured at higher electric fields and shown to be independent of changes in the electric field. Thus, under conditions where the total dAg concentration is in excess of the total Fab concentration, the method and quantitative expression which we developed is generally useful for the understanding of molecular interaction for an unlabeled monovalent receptor and its divalent ligand in free solution.

[Induction of quinone reductase and glutathion-s-transferase by dimethyl fumarate in rats]

OBJECTIVE

To assess induction of quinone reductase (QR) and glutathion-s-transferases (GSTs) by dimethyl fumarate (DMF) in major viscera of rats.

METHODS

Fodder fed to male Wistar rats was supplemented with 2.0% DMF, and blood specimens were collected form the rats 6 h, 24 h, 72 h, 1 week and 2 weeks after feeding, respectively, and then animals were killed. QR and GSTs activities were determined in rats' gland stomach, liver, lung, kidney and heart, and also QR, LDH and GPT activities in their sera were measured with enzyme dynamic methods.

RESULTS

Administration of DMF for 24 h, 72 h, 1 week and 2 weeks in rats can significantly increase activities of QR and GSTs in their gland stomach, liver, lung and kidney, as compared with those in controls (P < 0.0001, or P < 0.01), and their serum QR also significantly increased (P < 0.0001, or P < 0.01). But, DMF had no effect on activities of serum GPT and LDH (P > 0.05).

CONCLUSION

DMF is a potent induction agent for QR and GSTs in the gland stomach, liver, lung and kidney of rats, which suggests it will hopefully be a protective and antidotic agent against human antioxidant injury.

A Haemophilus influenzae gene that encodes a membrane bound 3-deoxy-D-manno-octulosonic acid (Kdo) kinase. Possible involvement of kdo phosphorylation in bacterial virulence

The lipopolysaccharide of Haemophilus influenzae contains a single 3-deoxy-D-manno-octulosonic acid (Kdo) residue derivatized with either a phosphate or an ethanolamine pyrophosphate moiety at the 4-OH position. In previous studies, we identified a kinase unique to H. influenzae extracts that phosphorylates Kdo-lipid IV(A), a key precursor of lipopolysaccharide in this organism. We have now identified the gene encoding the Kdo kinase by using an expression cloning approach. A cosmid library containing random DNA fragments from H. influenzae strain Rd was constructed in Escherichia coli. Extracts of 472 colonies containing individual hybrid cosmids were assayed for Kdo kinase activity. A single hybrid cosmid directing expression of the kinase was found. The kinase gene was identified by activity assays, sub-cloning, and DNA sequencing. When the putative kinase gene was expressed in E. coli behind a T7 promoter, massive overproduction of kinase activity was achieved ( approximately 8000-fold higher than in H. influenzae membranes). The catalytic properties and the product generated by the overexpressed kinase, assayed with Kdo-lipid IV(A) as the substrate, were the same as observed with H. influenzae membranes. Unexpectedly, the kinase gene was identical to a previously characterized open reading frame (orfZ), which had been shown to be important for establishing bacteremia in an infant rat model (Hood, D. W., Deadman, M. E., Allen, T., Masoud, H., Martin, A., Brisson, J. R., Fleischmann, R., Venter, J. C., Richards, J. C., and Moxon, E. R. (1996) Mol. Microbiol. 22, 951-965). However, based solely on the genome sequence of H. influenzae Rd, no biochemical function had been assigned to the product of orfZ, which we now designate kdkA ("Kdo kinase A"). Although Kdo phosphorylation may be critical for bacterial virulence of H. influenzae, it does not appear to be required for growth.

Potentiation of the action of anandamide on hippocampal slices by the fatty acid amide hydrolase inhibitor, palmitylsulphonyl fluoride (AM 374)

The electrically-evoked release of [3H]acetylcholine from hippocampal brain slices is inhibited by cannabinoid receptor agonists. The effect of palmitylsulphonyl fluoride (AM 374), a recently developed inhibitor of fatty acid amide hydrolase, in influencing the potency of exogenously added anandamide in this preparation was examined. Anandamide alone had relatively little effect on [3H]acetylcholine release. By contrast, in the presence of AM 374 (0.1 microM), anandamide produced a significant inhibition of [3H]acetylcholine release at all concentrations tested (0.1-10 microM). In addition to experiments with AM 374 the effects of N-(4-hydroxyphenyl)arachidonamide (AM 404), a putative anandamide uptake inhibitor, was also examined. However, AM 404 at concentrations up to 10 microM, was not found to significantly enhance the effect of anandamide on electrically-evoked [3H]acetylcholine release. These results indicate that AM 374 potently inhibits endogenous amidase activity and thus facilitates access of exogenous anandamide to cannabinoid receptors in the hippocampal tissue.

A PSTTLRE-form of cdc2-like gene in the marine microalga Dunaliella tertiolecta

To understand the genetic control of algal cell division cycle that pertains to phytoplankton bloom dynamics in the sea, we cloned and analyzed a gene coding for a cyclin-dependent kinase (CDK) for the chlorophyte Dunaliella tertiolecta. The cDNA cloned, 1061 bp long, contained an open reading frame of 314 amino acids. FASTA and GAP analyses showed that this sequence was most homologous to cdc2 out of all known cdks, with an identity of 54-68% and a similarity of 65-76% to cdc2 in higher plants, animals, and yeast. Several signature domains of cdc2 were identified from this sequence, although the PSTAIRE and GDSEID motifs were replaced with PSTTLRE and GDCELQ, respectively. Southern blot hybridization demonstrated that this gene occurred as a single copy in this species, and quantitative RT-PCR showed that the transcription of this gene was constitutive. The present results suggest that the universal cdc2 is conserved in the lower eukaryote with unique structural characteristics.

Genetic organization of alpha-bungarotoxins from Bungarus multicinctus (Taiwan banded krait): evidence showing that the production of alpha-bungarotoxin isotoxins is not derived from edited mRNAs

Two genomic DNAs with a size of approximately 2.8 kb, isolated from the liver of Bungarus multicinctus (Taiwan banded krait), encode the precursors of the long neurotoxins, alpha-Bgt(A31) and alpha-Bgt(V31), respectively. Both genes share virtually identical overall organization with three exons separated by two introns, which were inserted in the same positions in the coding regions of the genes. Moreover, their nucleotide sequences share approximately 98% identity. This result indicates that the two genes co-exist in the genome of B.multicinctus, and probably arose from gene duplication. The exon/intron structures of the alpha-Bgt genes were essentially the same as those reported for the short neurotoxins. This reflects that the long and short neurotoxins should share a common evolutionary origin. Comparative analyses on long neurotoxin and short neurotoxin genes showed that the protein coding regions of the exons were more diverse than the introns except for the signal peptide domain. This implies that the protein coding regions of the neurotoxins may have evolved via accelerated evolution. PCR amplification of venom gland cDNA mixtures revealed that only two amino acid sequences corresponding to alpha-Bgt(A31) and alpha-Bgt(V31) could be deduced from the cDNAs. The results of chromatographic analyses and protein sequencing again emphasized the view that, with the exception of alpha-Bgt(A31) and alpha-Bgt(V31), no other alpha-Bgt isotoxins with amino acid substitutions were present in B.multicinctus venom. In contrast to the proposition of Liu et al. ( Nucleic Acids Res., 1998,26, 5624-5629), our findings strongly suggest that each alpha-Bgt isotoxin is derived from the respective gene, and that alpha-Bgt RNA polymorphism does not originate from one single, intronless gene by the mechanism of RNA editing.