Investigation of the electrochemical and electrocatalytic behavior of single-wall carbon nanotube film on a glassy carbon electrode

The electrochemical behavior of a film of single-wall carbon nanotubes (SWNTs) functionalized with carboxylic acid groups was studied extensively on a glassy carbon (GC) electrode. One stable couple corresponding to the redox of the carboxylic acid group, which was supported by XPS and IR experiments, was observed. The electrode process involved four electrons, while the rate-determining step was a one-electron reduction. The SWNT film-modified electrode showed favorable electrocatalytic behavior toward the oxidation of biomolecules such as dopamine, epinephrine, and ascorbic acid.

The sequence of the human genome

A 2.91-billion base pair (bp) consensus sequence of the euchromatic portion of the human genome was generated by the whole-genome shotgun sequencing method. The 14.8-billion bp DNA sequence was generated over 9 months from 27,271,853 high-quality sequence reads (5.11-fold coverage of the genome) from both ends of plasmid clones made from the DNA of five individuals. Two assembly strategies-a whole-genome assembly and a regional chromosome assembly-were used, each combining sequence data from Celera and the publicly funded genome effort. The public data were shredded into 550-bp segments to create a 2.9-fold coverage of those genome regions that had been sequenced, without including biases inherent in the cloning and assembly procedure used by the publicly funded group. This brought the effective coverage in the assemblies to eightfold, reducing the number and size of gaps in the final assembly over what would be obtained with 5.11-fold coverage. The two assembly strategies yielded very similar results that largely agree with independent mapping data. The assemblies effectively cover the euchromatic regions of the human chromosomes. More than 90% of the genome is in scaffold assemblies of 100,000 bp or more, and 25% of the genome is in scaffolds of 10 million bp or larger. Analysis of the genome sequence revealed 26,588 protein-encoding transcripts for which there was strong corroborating evidence and an additional approximately 12,000 computationally derived genes with mouse matches or other weak supporting evidence. Although gene-dense clusters are obvious, almost half the genes are dispersed in low G+C sequence separated by large tracts of apparently noncoding sequence. Only 1.1% of the genome is spanned by exons, whereas 24% is in introns, with 75% of the genome being intergenic DNA. Duplications of segmental blocks, ranging in size up to chromosomal lengths, are abundant throughout the genome and reveal a complex evolutionary history. Comparative genomic analysis indicates vertebrate expansions of genes associated with neuronal function, with tissue-specific developmental regulation, and with the hemostasis and immune systems. DNA sequence comparisons between the consensus sequence and publicly funded genome data provided locations of 2.1 million single-nucleotide polymorphisms (SNPs). A random pair of human haploid genomes differed at a rate of 1 bp per 1250 on average, but there was marked heterogeneity in the level of polymorphism across the genome. Less than 1% of all SNPs resulted in variation in proteins, but the task of determining which SNPs have functional consequences remains an open challenge.

Evolutionary analyses of the human genome

The completion of the human genome will greatly accelerate the development of a new branch of science--evolutionary genomics. We can now directly address important questions about the evolutionary history of human genes and their regulatory sequences. Computational analyses of the human genome will reveal the number of genes and repetitive elements, the extent of gene duplication and compositional heterogeneity in the human genome, and the extent of domain shuffling and domain sharing among proteins. Here we present some first glimpses of these features.

N-methyl-D-aspartate receptor activation results in regulation of extracellular signal-regulated kinases by protein kinases and phosphatases in glutamate-induced neuronal apototic-like death

Extracellular signal-regulated kinases (ERK1/ERK2) have been shown transiently activated and involved in excitotoxicity. We searched for upstream molecules responsible for the regulation of glutamate-induced ERK1/ERK2 activation and ERK1/ERK2-mediated apototic-like death in cultured rat cortical neurons. ERK1/ERK2 activation (monitored by anti-active ERK1/ERK2 antibody) was almost completely prevented by blockage of NMDA receptor (NMDA-R) or elimination of extracellular Ca(2+), but not any other glutamate receptor or L-type voltage-gated Ca(2+) channel. It was prevented largely by inhibition of protein kinase C (PKC), protein-tyrosine kinases (PTK), respectively, but mildly by that of CaM kinase II. Combined inhibition of CaM kinase II (but not PTK) and PKC had an additive effect. Reversion of ERK1/ERK2 activation was largely prevented by inhibition of protein phosphatase (PP) 1 or protein tyrosine phosphatase (PTP). Combined inhibition of PP 1 and PTP had no additive effect. Glutamate-induced apoptotic-like death (determined by DAPI staining) was largely prevented by inhibition of NMDA-R, PKC, CaM kinase II, PTK and MEK1/MEK2 (ERK1/ERK2 kinase), respectively. Combined inhibition of CaM kinase II (but not PKC or PTK) and MEK1/MEK2 had an additive effect. Glutamate-induced apoptotic-like death was promoted by inhibition of PP1 and PTP, respectively. The above results suggested that in glutamate-induced cortical neurotoxicity ERK1/ERK2 activation be mainly mediated by NMDA-R. Subsequently, a pathway dependent on both PKC and PTK was mainly involved, which was also mainly responsible for ERK1/ERK2-mediated apoptotic-like death, and a CaM kinase II-dependent pathway was relatively mildly involved. Reversion of ERK1/ERK2 activation was mainly mediated by a pathway dependent on both PP1 and PTP, which might be involved in the restrain of glutamate-induced neurotoxicity.

Densities, length proportions, and other distributional features of repetitive sequences in the human genome estimated from 430 megabases of genomic sequence

The densities of repetitive elements in the human genome were calculated in each GC content class using non-overlapping windows of 50kb. The density of Alu is two to three times higher in GC-rich regions than in AT-rich regions, while the opposite is true for LINE1. In contrast, LINE2 and other elements, such as DNA transposons, are more uniformly distributed in the genome. The number of Alus in the human genome was estimated to be 1.4 million, higher than previous estimates. About 40% of the autosomes and approximately 51% of the X and Y chromosomes are occupied by repetitive elements. In total, the human genome is estimated to contain more than 4 million repetitive elements. The GC contents (%) of repetitive elements and their flanking regions were also calculated. The GC contents of almost all kinds of repeats are positively correlated with the window GC contents, suggesting that a repetitive sequence is subject to the same mutation pressure as its surrounding regions, so it tends to have the same GC content as its surrounding regions. This observation supports the regional mutation hypothesis. The only two exceptions are AluYa and AluYb8, the two youngest Alu subfamilies. The GC content of AluYb8 is negatively correlated with that of its surrounding regions, while AluYa shows no correlation, suggesting different insertion patterns for these two young Alu subfamilies. This suggestion was supported by the fact that the average genetic distance between members of AluYb8 in each GC window class is positively correlated with the GC content of the window, but no correlation was found for AluYa. AluYa is more frequent in Y chromosome than in other chromosomes; the same is true for LTR retroviruses. This pattern might be correlated with the evolutionary history of Y chromosome.

Selection of resistance-conferring mutations in HIV-1 by the nucleoside reverse transcriptase inhibitors (+/-)dOTC and (+/-)dOTFC

The patterns of resistance-conferring mutations that are selected in HIV-1 reverse transcriptase (RT) by the racemates of 2'-dideoxy-3'-oxa-4'-thiocytidine (+/-)dOTC and its fluorinated derivative (+/-)dOTFC were characterized. Genotypic and phenotypic analyses of HIV-1 clinical isolates and HXB2D variants selected with (+/-)dOTC and (+/-)dOTFC were performed in primary cells and in the MT-2 T cell line. HIV-1 variants selected with (+/-)dOTC or (+/-)dOTFC displayed fivefold decreased susceptibility to the respective compounds. A substitution of methionine to valine was identified at position 184 (M184V) in variants selected with (+/-)dOTC. In contrast, a mutation of lysine to arginine at position 65 (K65R) was found in variants selected with (+/-)dOTFC. These patterns of selected mutations differ from those seen with the individual enantiomers. Studies with mutated recombinant HXB2D-M184V and -K65R confirmed that these mutations are important for phenotypic resistance in MT-2 cells. Clinical isolates that display resistance to (-)2'-deoxy-3'-thiacytidine (3TC) also showed cross-resistance to (+/-)dOTC and (+/-)dOTFC. These studies demonstrate that similar genotypes may be selected by the dOTC and dOTFC compounds to those with the structurally related drug 3TC.

The p53-inducible gene EI24/PIG8 localizes to human chromosome 11q23 and the proximal region of mouse chromosome 9

Activation of the p53 tumor suppressor leads to either a cell cycle arrest or to apoptosis and the factors that influence these responses are poorly understood. It is clear, however, that p53 regulates these processes by inducing a series of downstream target genes. One recently identified p53-target gene, EI24 (alias PIG8), induces apoptosis when ectopically expressed. To better understand the biological properties of EI24 and its potential relevance to disease, in particular cancer, we determined the chromosomal location and pattern of gene expression of EI24. EI24 is widely expressed in adult tissues and throughout mouse embryogenesis. The genomic locus of EI24 was mapped to the proximal region of mouse chromosome 9 and human chromosome 11q23-->q24, a region frequently altered in human cancers. These results suggest that EI24 may play an important role in the p53 tumor suppressor pathway.

[Detection of the asymptomatic infection by human papillomavirus in pregnant women and neonates]

OBJECTIVE

To investigate the state of human papillomavirus (HPV) infection in similar average-aged pregnant women of different gestational periods, in the puerperium and neonates.

METHODS

Polymerase chain reaction (PCR) assay was employed to detect HPV-6, 11, 16 and 18 DNA in 30 pregnant women in the first trimester, 42 in the second and 31 in the third (who were followed up to their puerperium), and 30 non-pregnant women asking for intrauterine device in our out-patient clinic were taken as controls. Average age in the four groups showed no significant difference (P > 0.05). Samples from cervical, vaginal exfoliated cells, maternal peripheral blood and nasopharyngeal secretion of the newborns were examined respectively.

RESULTS

(1) In the first trimester, HPV-DNA was detected in the cervical, vaginal exfoliated cells of 5 cases and in the maternal peripheral blood of 7 cases. (2) In the second trimester, HPV-DNA was detected in the cervical, vaginal exfoliated cells of 12 cases and in the maternal peripheral blood of 11 cases. (3) In the third trimester, HPV-DNA was detected in the cervical, vaginal exfoliated cells of 23 cases and in the maternal peripheral blood of 18 cases. (4) In the puerperium, HPV-DNA was detected in samples of cervical, vaginal exfoliated cells of 8 cases and maternal peripheral blood of 7 cases. (5) In the control group, HPV-DNA was detected in the cervical, vaginal exfoliated cells of 8 cases and in the maternal peripheral blood of 6 cases. (6) Consecutive examinations were carried out in 31 pregnant women from the third trimester, through labor to 6 weeks of postpartum. HPV-DNA was positive in the cervical, vaginal samples of 17, 21 and 8 cases, respectively, according to the perinatal periods, and in the maternal peripheral blood of 14, 13 and 7 cases, respectively. The result through the above gestational stages was fluctuated in the cervical, vaginal samples of 6 cases and in the maternal peripheral blood of 7 cases. (7) Successive examinations in infants at time of birth, 48-72 h and 6 weeks after birth showed positive HPV-DNA in the nasopharyngeal secretion of 13, 6 cases and 1 case with respect to the examining periods. (8) The positive cases were mainly infected by HPV-16, 18.

CONCLUSIONS

(1) Infective rate of HPV is statistically significant in the third trimester, but no significant difference exists among the first trimester, the second trimester, the puerperium or the non-pregnancies. (2) Examining consecutively, the HPV positive rate is found to be decreased after delivery, the positive expression of HPV during the gestational periods exhibited fluctuation. (3) Infective rate of HPV in the neonatal nasopharyngeal specimens tends to decrease with time after delivery.

Biphenylsulfonamide endothelin receptor antagonists. 2. Discovery of 4'-oxazolyl biphenylsulfonamides as a new class of potent, highly selective ET(A) antagonists

The synthesis and structure-activity relationship (SAR) studies of a series of 4'-oxazolyl-N-(3,4-dimethyl-5-isoxazolyl)[1, 1'-biphenyl]-2-sulfonamide derivatives as endothelin-A (ET(A)) receptor antagonists are described. The data reveal a remarkable improvement in potency and metabolic stability when the 4'-position of the biphenylsulfonamide is substituted with an oxazole ring. Additional 2'-substitution of an acylaminomethyl group further increased the binding activity and provided one of the first subnanomolar ET(A)-selective antagonists in the biphenylsulfonamide series (17, ET(A) K(i) = 0.2 nM). Among the compounds described, 3 (N-(3,4-dimethyl-5-isoxazolyl)-4'-(2-oxazolyl)[1, 1'-biphenyl]-2-sulfonamide; BMS-193884) had the optimum pharmacological profile and was therefore selected as a clinical candidate for studies in congestive heart failure.

[Comparison of the effects of xianyu tablet and its component on electrophoretic mobility of serum LDL and expression of ET-1 mRNA and iNOS mRNA of vessel wall in atherosclerotic rabbits]

Xiaoyu tablet, a compound preparation of Chinese herbal medicines, consists of Radix Salviae Miltiorrhizae(SM) and Fructus Crataegi(FC) extracts. To determine whether the proved recipe was reasonable, the effects of Xiaoyu tablet and its component on electrophoretic mobility of serum LDL and expression of ET-1 mRNA and iNOS mRNA of vessel wall in atherosclerotic rabbits were observed. The results indicated that inhibition of expression iNOS mRNA in vessel wall by Xiaoyu tablet was the same as its single extract of SM or FC, but Xiaoyu talbet was superior to SM or FC extract in reduction of electrophoretic mobility of serum LDL and inhibition of ET-1 mRNA expression in vessel wall. These results suggested that there was obvious synergism on prevention and treatment of atherosclerosis when both of the Chinese herbal medicines were simultaneously used.

12-O-tetradecanoylphorbol-13-acetate (TPA)-induced c-Jun N-terminal kinase (JNK) phosphatase renders immortalized or transformed epithelial cells refractory to TPA-inducible JNK activity

c-Jun N-terminal kinase (JNK) regulates gene expression in response to various extracellular stimuli. JNK can be activated by the tumor promoting agent, 12-O-tetradecanoylphorbol-13-acetate (TPA) in normal human oral keratinocytes but not in human keratinocytes that have been immortalized (HOK-16B and HaCaT) or transformed (HOK-16B-Bap-T) nor in a cervical carcinoma cell line (HeLa). The refractory JNK activation response to TPA is not due a defect in the JNK pathway, because JNK can be activated by other stimuli, e.g. UV irradiation and an alkylating agent N-methyl-N'-nitrosoguanidine in these immortalized or transformed cells. More importantly, the refractory JNK and JNKK activation response to TPA can be restored by treatment of the cells with a combination of TPA and a protein-tyrosine phosphatase inhibitor, sodium orthovanadate. Furthermore, pretreatment of cells with TPA partially inhibited UV- or N-methyl-N'-nitrosoguanidine-induced JNK activity. These results suggest that a TPA-inducible, orthovanadate-sensitive protein-tyrosine phosphatase may specifically down-regulate JNK signaling pathway in these immortalized/transformed epithelial cells. In contrast, ERK and p38/Mpk2 are not regulated by this TPA-induced phosphatase. This putative protein-tyrosine phosphatase appears to be JNK pathway-specific.

Absence of cardiolipin in the crd1 null mutant results in decreased mitochondrial membrane potential and reduced mitochondrial function

Cardiolipin (CL) is a unique phospholipid which is present throughout the eukaryotic kingdom and is localized in mitochondrial membranes. Saccharomyces cerevisiae cells containing a disruption of CRD1, the structural gene encoding CL synthase, have no CL in mitochondrial membranes. To elucidate the physiological role of CL, we compared mitochondrial functions in the crd1Delta mutant and isogenic wild type. The crd1Delta mutant loses viability at elevated temperature, and prolonged culture at 37 degrees C leads to loss of the mitochondrial genome. Mutant membranes have increased phosphatidylglycerol (PG) when grown in a nonfermentable carbon source but have almost no detectable PG in medium containing glucose. In glucose-grown cells, maximum respiratory rate, ATPase and cytochrome oxidase activities, and protein import are deficient in the mutant. The ADP/ATP carrier is defective even during growth in a nonfermentable carbon source. The mitochondrial membrane potential is decreased in mutant cells. The decrease is more pronounced in glucose-grown cells, which lack PG, but is also apparent in membranes containing PG (i.e. in nonfermentable carbon sources). We propose that CL is required for maintaining the mitochondrial membrane potential and that reduced membrane potential in the absence of CL leads to defects in protein import and other mitochondrial functions.

[Antigen loading on dendritic cells affects the cell function in stimulating T cells]

OBJECTIVE

To study the effect of antigen loading on dendritic cells (DC).

METHODS

DCs collected from peripheral blood monocytes were loaded with a tumor antigen from XG-7 cell line. These DCs were then co-cultured with allogeneic T cells and were compared with those DCs without antigen exposure.

RESULTS

Although DCs showed no change in their phenotypes after cultured with the antigen, they secreted more IL-12, and became more powerful in allogenic mixed lymphocyte reaction (MLR). Antigen-loaded DC stimulated more CD(4)(+) cells to proliferate than nonantigen-loaded DCs did. These CD(4)(+) cells did not kill XG-7 cells, but promoted CD(8)(+) cells' ability to inhibit the XG-7 proliferation.

CONCLUSION

The proliferation of CD(4)(+) cells after cultured with DC may become an indicator for the function of antigen loaded DC and for the efficiency of DC immunotherapy.

NGF-mediated alteration of NF-kappaB binding activity after partial immunolesions to rat cholinergic basal forebrain neurons

There are age-associated cognitive and cholinergic deficits in the neurotrophin-dependent cholinergic basal forebrain neurons (CBFNs). There are also increases in the activity of the transcription factor NF-kappaB in the aged rodent brain that may reflect chronic enhancement of stress response signaling. We used partial immunolesions (PIL) to CBFN to examine the role of endogenous NGF on choline acetyltransferase (ChAT) activity and NGF-mediated NF-kappaB alteration after cholinergic deafferentation. We injected 192 IgG-saporin, an immunotoxin selectively taken up by neurotrophin receptor p75(NTR)-bearing neurons, into lateral ventricles, followed by infusions of anti-NGF to assess NF-kappaB, ChAT and NGF responses to PIL after anti-NGF infusion. Treatment with anti-NGF decreased ChAT activity by 17-34% in the cortex, hippocampus, and olfactory bulb and PIL decreased ChAT activity by 47-73%. Changes in AChE activity levels paralleled those observed for ChAT after PIL. NGF protein levels in the olfactory bulb, but not the cortex or hippocampus, increased significantly after PIL treatment. Infusion of anti-NGF abolished the PIL-induced eight-fold NGF increase in CNS. NF-kappaB binding activity to the IgG-kappaB and ChAT specific NF-kappaB consensus sequences, increased in the cortex but not hippocampus after PIL followed by anti-NGF infusion. It is likely that immunolesion-induced changes in ambient NGF levels may perturb NF-kappaB activity.

Structural examination of the nickel site in chromatium vinosum hydrogenase: redox state oscillations and structural changes accompanying reductive activation and CO binding

An X-ray absorption spectroscopic study of structural changes occurring at the Ni site of Chromatium vinosum hydrogenase during reductive activation, CO binding, and photolysis is presented. Structural details of the Ni sites for the ready silent intermediate state, SI(r), and the carbon monoxide complex, SI-CO, are presented for the first time in any hydrogenase. Analysis of nickel K-edge energy shifts in redox-related samples reveals that reductive activation is accompanied by an oscillation in the electron density of the Ni site involving formally Ni(III) and Ni(II), where all the EPR-active states (forms A, B, and C) are formally Ni(III), and the EPR-silent states are formally Ni(II). Analysis of XANES shows that the Ni site undergoes changes in the coordination number and geometry that are consistent with five-coordinate Ni sites in forms A, B, and SI(u); distorted four-coordinate sites in SI(r) and R; and a six-coordinate Ni site in form C. EXAFS analysis reveals that the loss of a short Ni-O bond accounts for the change in coordination number from five to four that accompanies formation of SI(r). A shortening of the Ni-Fe distance from 2.85(5) A in form B to 2.60(5) A also occurs at the SI level and is thus associated with the loss of the bridging O-donor ligand in the active site. Multiple-scattering analysis of the EXAFS data for the SI-CO complex reveals the presence of Ni-CO ligation, where the CO is bound in a linear fashion appropriate for a terminal ligand. The putative role of form C in binding H(2) or H(-) was examined by comparing the XAS data from form C with that of its photoproduct, form L. The data rule out the suggestion that the increase in charge density on the NiFe active site that accompanies the photoprocess results in a two-electron reduction of the Ni site [Ni(III) --> Ni(I)] [Happe, R. P., Roseboom, W., and Albracht, S. P. J. (1999) Eur. J. Biochem. 259, 602-608]; only subtle structural differences between the Ni sites were observed.

Single nucleotide polymorphism hunting in cyberspace

Large-scale sequencing of human cDNA and genomic DNA libraries has produced a large collection of sequence data in public databases. To date, >900,000 human expressed sequence tag (EST) sequences and >80,000,000 bases of genomic DNA sequence have been deposited in Genbank. This ever-expanding data set is a rich source of gene-associated and anonymous single nucleotide polymorphisms (SNPs). DNA sequence variations can be found by comparing the sequences of redundant ESTs and by comparing sequences from overlapping genomic clones. Initial studies have shown that, with proper computer screening, informative SNP markers can be developed from these DNA databases in an efficient and cost-effective manner. Complete public access to these databases will allow individual investigators to add biological value to the human sequence data generated by large-scale sequencing centers.

Study on DNA polymorphism at D1S8 locus in Hebei Han population

OBJECTIVE

To study the polymorphism at D1S8 locus and to provide basic information for the construction of DNA fingerprint database and the application in forensic medicine.

METHODS

Minisatellite variant repeat-polymerase chain reaction (MVR-PCR) and polyacrylamide gradient gel electrophoresis followed by silver staining were used to detect the variant repeat sequences at D1S8 locus of 240 unrelated individuals in Hebei Han population, and digital codes were obtained.

RESULTS

Each individual obtained about 30 digital codes, in which none of two unrelated individuals had the same code. The probability of identity of 30 digital codes was 3.55x10(-11). The percentages of three repeat units, a-type, t-type and o-type were 54.77%, 42.54% and 2.69% respectively. The heterozygosity (H) was 0.9837. The excluding probability of paternity(EPP) and polymorphism information content(PIC) were 0.9669 and 0.9833 respectively.

CONCLUSION

Because of its high polymorphic nature, D1S8 locus is a valuable marker for forensic identification and paternity testing.

Consensus and comprehensive linkage maps of bovine chromosome 7

The objective of this project was to integrate the currently available linkage maps for bovine chromosome 7 (BTA7) by combining data sets from eight research groups. A total of 54 unique markers were typed in eight pedigrees. Multilocus linkage analysis with CRI-MAP produced a bovine chromosome 7 consensus framework map of 27 loci ordered with odds greater than 1000:1. Furthermore, we present a bovine chromosome 7 comprehensive map integrating 54 loci. The locus order is in general agreement with the recently published linkage maps except for one discrepancy. The order of loci BM9289, BMS713, and ILSTS001 was reversed in the consensus framework map relative to the published USDA-MARC bovine chromosome 7 linkage map.

Differential alterations of NF-kappaB to oxidative stress in primary basal forebrain cultures

Oxidative stress has been linked to neuronal cell death resulting from either acute insults due to ischemia, trauma, excitotoxicity, or chronic neurodegenerative diseases. Cholinergic basal forebrain neurons (CBFNs) compete for nerve growth factor (NGF) synthesized in the hippocampus and cortex via retrograde transport. NGF affects CBFN survival and cholinergic function via activation of the NF-kappaB transcription factor and this signaling pathway appears to be impaired in aged rats. Here, we demonstrate that activation of NF-kappaB in basal forebrain primary culture via treatment with hydrogen peroxide or TNF-alpha is predominantly restricted to CBFNs, and that NF-kappaB activation appears to mostly affect p65 translocation to the nucleus, but not the p50 subunit. These results are consistent with NF-kappaB activation being a part of recovery processes after acute oxidative stress. Since p50 or p49 (also called p52) binding to promoter sites does not stimulate transcription - both p50 and p49 lack an activating domain - and p65 does contain an activating domain and thus can act as a transcription enhancer, differential translocation of different NF-kappaB dimers can act as repressors of constitutive activity or enhancers. These results are in agreement with the hypothesis that p50/p65 is the active trans-activating species of NF-kappaB, as compared to p50/p50 homodimers which bind to NF-kappaB binding sites but do not trans-activate promoters. Our results also suggest that selective activation of different NF-kappaB dimer species may have regulatory significance in neuronal responses to acute or chronic insults to CNS. Thus, increased p65 translocation could have enhancing effects while increased p50 translocation could have a repressor role. Manipulation of the types of NF-kappaB species being translocated could provide a basis for therapeutic strategies.

Repeated immunolesions display diminished stress response signal

Cholinergic basal forebrain neurons (CBFNs) retrogradely transport neurotrophins released in the hippocampus and cortex as part of a general response to injury in a process that is impaired in the aged rodent and can be spared by the exogenous addition of pharmacological doses of nerve growth factor (NGF). This observation suggests that components of stress response signal transduction pathways in the aged CNS can be exogenously activated. The extent and mechanism of the endogenous stimulation of NGF in response to injury can be mimicked via treatment with 192 IgG-saporin of rat CNS, an immunolesion model. Here we report on the use of a conditioning lesion paradigm to determine if repeated partial immunolesions have a conditioning effect on the immunolesion-induced increases in NGF protein or decreases in choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activity. We report that chronic repeated immunolesions, as used here, were not as effective as a one time equivalent immunolesion in terms of induced NGF protein increases or decreasing ChAT and AChE activity in the hippocampus and cortex. Thus, chronic lesions resulting in cholinergic impairment typical of the aged CNS may differ from acute toxic models as a result of desensitization due to a conditioning effect of chronic subthreshold lesioning events in the CNS.

[Examinations of distortion product otoacoustic emission in hereditary progressive non-syndromic hearing loss]

OBJECTIVE

To evaluate the hearing function in patients with hereditary progressive non-syndromic hearing loss.

METHODS

Distortion product otoacoustic emissions (DPOAE) and pure tone audiometry were carried out in 52 individuals from a family with non-syndromic hearing loss and 15 persons with normal hearing.

RESULTS

1. Sensorineural hearing loss (SNHL) was found in 34 individuals of the family. Among these individuals, DPOAE was totally absent in 15 cases (29 ears) with pure tone average > or = 40 dB and low amplitude or absent middle to high frequencies in 12 cases (23 ears) with high frequency hearing loss but pure tone average < or = 35 dB. 2. Among 21 individuals (42 ears) with normal audiograms, DPOAE presented lower amplitude or absent high and middle frequencies in 12 individuals.

CONCLUSION

DPOAE can be used in identification of subclinical pathologic alterations in the cochlea. This would be of particular value in early diagnosis and genetic consultation.

Diphosphorylation of extracellular signal-regulated kinases and c-Jun N-terminal protein kinases in brain ischemic tolerance in rat

Extracellular signal-regulated kinases (ERKs) and c-Jun N-terminal protein kinases (JNKs) activation in brain ischemic tolerance were examined by Western immunoblot. ERK but not JNK diphosphorylation (activation) were increased after preconditioning ischemia. The increased JNK1 but not ERK diphosphorylation after lethal ischemia was eliminated by pretreatment with preconditioning ischemia. The results suggest that the elimination of JNK1 activation after lethal ischemia by preconditioning ischemia may be one of the important protective mechanisms in ischemic tolerance, and ERKs activation may be involved in the induction of the protective responses.

The genome sequence of Drosophila melanogaster

The fly Drosophila melanogaster is one of the most intensively studied organisms in biology and serves as a model system for the investigation of many developmental and cellular processes common to higher eukaryotes, including humans. We have determined the nucleotide sequence of nearly all of the approximately 120-megabase euchromatic portion of the Drosophila genome using a whole-genome shotgun sequencing strategy supported by extensive clone-based sequence and a high-quality bacterial artificial chromosome physical map. Efforts are under way to close the remaining gaps; however, the sequence is of sufficient accuracy and contiguity to be declared substantially complete and to support an initial analysis of genome structure and preliminary gene annotation and interpretation. The genome encodes approximately 13,600 genes, somewhat fewer than the smaller Caenorhabditis elegans genome, but with comparable functional diversity.

Prostate stem cell antigen (PSCA) expression increases with high gleason score, advanced stage and bone metastasis in prostate cancer

Prostate stem cell antigen (PSCA) is a recently defined homologue of the Thy-1/Ly-6 family of glycosylphosphatidylinositol (GPI)-anchored cell surface antigens. PSCA mRNA is expressed in the basal cells of normal prostate and in more than 80% of prostate cancers. The purpose of the present study was to examine PSCA protein expression in clinical specimens of human prostate cancer. Five monoclonal antibodies were raised against a PSCA-GST fusion protein and screened for their ability to recognize PSCA on the cell surface of human prostate cancer cells. Immunohistochemical analysis of PSCA expression was performed on paraffin-embedded sections from 25 normal tissues, 112 primary prostate cancers and nine prostate cancers metastatic to bone. The level of PSCA expression in prostate tumors was quantified and compared with expression in adjacent normal glands. The antibodies detect PSCA expression on the cell surface of normal and malignant prostate cells and distinguish three extracellular epitopes on PSCA. Prostate and transitional epithelium reacted strongly with PSCA. PSCA staining was also seen in placental trophoblasts, renal collecting ducts and neuroendocrine cells in the stomach and colon. All other normal tissues tested were negative. PSCA protein expression was identified in 105/112 (94%) primary prostate tumors and 9/9 (100%) bone metastases. The level of PSCA expression increased with higher Gleason score (P=0.016), higher tumor stage (P=0.010) and progression to androgen-independence (P=0. 021). Intense, homogeneous staining was seen in all nine bone metastases. PSCA is a cell surface protein with limited expression in extraprostatic normal tissues. PSCA expression correlates with tumor stage, grade and androgen independence and may have prognostic utility. Because expression on the surface of prostate cancer cells increases with tumor progression, PSCA may be a useful molecular target in advanced prostate cancer.

Diphosphorylation and involvement of extracellular signal-regulated kinases (ERK1/2) in glutamate-induced apoptotic-like death in cultured rat cortical neurons

Glutamate-induced excitotoxicity, with certain characteristics of apoptosis, has been implicated in a variety of neuronal degenerative disorders. In some physiological cases, extracellular signal-regulated kinases (ERK1/2) are activated by stimulation of glutamate receptors. In the present study, the activation (diphosphorylation) and role of ERK1/2 in glutamate-induced apoptotic-like death in cultured cortical neurons were investigated. Protein levels and activation (diphosphorylation) levels of ERK1/2 were examined by Western immunoblot, probed with anti-ERK1/2 and anti-active (diphosphorylated) ERK1/2 antibodies, respectively. Apoptotic-like death was determined by DAPI staining. Before a remarkable increase of apoptotic-like cell death was observed at 9-18 h after 15 min exposure to 50 microM glutamate, diphosphorylation levels of ERK1/2 were rapidly increased, peaked at 5-15 min of the exposure, and reverted to sham control level 3 h after the exposure, while the protein levels of ERK1/2 were unaffected. The glutamate concentration effective for inducing apoptotic-like cell death was correlated with that for inducing ERK1/2 diphosphorylation. Both ERK1/2 diphosphorylation and the apoptotic-like cell death were largely prevented by MK-801, a specific NMDA receptor (a subtype receptor of glutamate) antagonist, or the elimination of extracellular Ca(2+) with EGTA. PD98059, a specific inhibitor of ERK1/2 kinase, completely inhibited ERK1/2 diphosphorylation and partially inhibited the apoptotic-like cell death. These results suggest that largely via NMDA receptor-mediated influx of extracellular Ca(2+), ERK1/2 were rapidly and transiently activated and were involved in glutamate-induced apoptotic-like death in cultured rat cortical neurons.