Dexamethasone modulates the development of morphine tolerance and expression of glutamate transporters in rats

We recently demonstrated an increase in spinal cerebrospinal fluid (CSF) excitatory amino acids (EAAs) in morphine-tolerant rats after morphine challenge. The present study examined whether co-infusion of the glucocorticoid dexamethasone (DEX) co-infusion inhibited morphine tolerance and the morphine challenge-induced EAAs increase after long-term morphine infusion. Intrathecal (i.t.) catheters and one microdialysis probe were implanted to male Wistar rats. Rats were divided into four groups: i.t. morphine (15 microg/h), saline (1 microl/h), DEX (2 microg/h), or DEX (2 microg/h) plus morphine (15 microg/h) infusion for 5 days. Tail-flick responses were examined before drug infusion and daily after the start of infusion for 5 days. Moreover, on day 5 after morphine challenge (50 microg, i.t.), CSF EAAs was also measured. Rat spinal cords were removed on day 5, and prepared for Western blot analysis of different glutamate transporters (GTs). The AD50 (analgesic dose) on day 5 was 1.33 microg in saline-infused rats, 83.84 microg in morphine-tolerant rats, and 10.15 microg in DEX plus morphine co-infused rats. Single DEX (2 microg, i.t.) injection did not enhance morphine's antinociceptive effect in either naïve or morphine-tolerant rats. No difference in CSF EAA level was observed in all groups between baseline (before drug infusion) and on day 5 after tolerance developed. Surprisingly, on day 5, after morphine challenge, an increase in glutamate and aspartate (284+/-47% and 201+/-18% of basal) concentration was observed, and morphine lost its antinociceptive effect (maximum percent effect, MPE = 41+/-12%), whereas DEX/morphine co-infusion inhibited morphine-evoked EAA increase with a MPE = 97+/-2%. DEX co-infusion prevented the downregulation of glial glutamate transporters (GLAST (Glu-Asp transporter) and GLT-1 (Glu transporter-1)), but not the neuronal GT EAAC1 (excitatory amino acid carrier). Upregulation of GLT-1 was also observed (204+/-20% of basal). DEX co-infusion inhibits the morphine-challenge induced EAA increase and prevents the loss of morphine's antinociceptive effect after long-term morphine infusion.

Bacterial diversity in Malan ice core from the Tibetan Plateau

Three ice core samples were collected from the Malan ice core drilled from the Tibetan Plateau, and three 16S rDNA clone libraries by direct amplification from the ice-melted water were established. Ninety-four clones containing bacterial 16S rDNA inserts were selected. According to restriction fragment-length polymorphism analysis, 11 clones were unique in the library from which they were obtained and used for partial sequence and phylogenetic analysis, and compared with 8 reported sequences from the same ice core at depth 70 m. Differences among the samples were apparent in clone libraries. The phylotypes were dominated by the Proteobacteria group, Acinetobacter sp. and Cytophaga-Flavobacterium-Bacteroides (CFB) group. They accounted for 92.5% (Proteobacteria), 100% (Acinetobacter sp.), 34.4% (CFB) and 100% (beta-Proteobacteria) in the clone libraries from the samples at ice depths 35, 64, 70, and 82 m, respectively. The Acinetobacter sp. was only found in the deposition at ice depth 82 m and closely clustered with gamma-Proteobateria. Two members (Malan A-21 and 101) of alpha-Proteobacteria from the sample of 35 m and two (Malan B-26 and 48) of beta-Proteobacteria of 64 m were loosely clustered (< 95% similarity) with known bacteria, represented new genera in ice bacteria.

Comparison of four methods for sperm preparation for IUI

We compared the pregnancy rates and sperm characteristics of semen prepared by the albumin, Percoll, Puresperm, and swim-up methods. Semen analysis was performed by a computer-assisted system (CASA). The overall pregnancy rate was 14% per patient and 11% per cycle. The albumin and Percoll methods had the highest pregnancy rates, up to 12% per cycle. We then compared each method with the albumin method. The swim-up technique yielded the highest percentage of motile sperm. The Percoll method yielded statistically significant changes in average path velocity and straight-line velocity, while the Puresperm method revealed the same statistical changes in total concentration and hyperactive motile sperm percentage. After adjusting for age, methods, and CASA estimates, only straight-line velocity was significantly correlated with pregnancy. Although the Percoll method was associated with the best pregnancy rate, this product has been withdrawn from the market because of toxic contamination. Puresperm had replaced it in our laboratory but showed an unsatisfactory pregnancy rate. The swim-up method is the best choice for IUI.

Comparison of nitric oxide production and motion characteristics after 3-layer percoll and IxaPrep preparation methods of human sperm

OBJECTIVE

To compare two different spermatozoa preparation mediums, the three-layer Percoll (Sigma, St. Louis, MO; salica-based) and the IxaPrep (Medicult, Copenhagen, Denmark; non-salica based, polysucrose medium) method, with respect to recovery of pregressive motile sperm and various sperm motion characteristics. Analysis was determined by computer-aided sperm analysis and nitric oxide (NO) production of the supernatant after centrifugation.

METHOD

Thirty-nine semen specimens were obtained from men who presented for semen analysis and each of them was divided into two aliquots for preparation with the two mediums mentioned above. The motile sperm recovery, motility percentage and motion parameters were measured for each semen specimen (n=39) before and after preparation using one of the two above methods. The NO was measured using the chemiluminscence method after centrifugation.

RESULTS

Recovery rate was higher in the IxaPrep group (Ixaprep: 45.4+/-28.7% versus Percoll: 32.3+/-22.7%; p<0.05). The other motion characteristics such as average path velocity (VAP) and straight line velocity (VSL) were better than those of fresh semen samples [VAP: 72+/-17.2 micro m/s (Percoll), 62.8+/-18.2 micro m/s (Ixaprep) vs 52.2+/-9.5 micro m/s (fresh); p<0.05; VSL: 51.8+/-13.4 micro m/s (Percoll), 44.8+/-12.9 micro m/s (Ixaprep) vs 38.6+/-7.9 micro m/s (fresh); p<0.05]. The motility between fresh and post-preparation semen samples had no significant difference. Hyperactivation of the sperm was improved in the IxaPrep group compared with fresh sperm (Percoll: 24.7+/-16.9% and IxaPrep: 20.5+/-10.5% versus fresh: 9.2+/-9.2%; p<0.05). NO produced in the IxaPrep method was significantly lower than that in the Percoll method (Ixaprep: 0.24+/-0.3 micro M versus Percoll: 0.54+/-0.91 micro M; p<0.05).

CONCLUSION

Our data suggests that the IxaPrep method provides a better recovery rate, but that other motion characteristics did not demonstrate any significant difference. The lower level of NO produced in the IxaPrep preparation method may suggest that better sperm quality achieved is due to the decreased NO production.

Isolation and characterization of the major form of human MUC18 cDNA gene and correlation of MUC18 over-expression in prostate cancer cell lines and tissues with malignant progression

Ectopical expression of huMUC18, a cell adhesion molecule in the immunoglobulin gene superfamily, causes a non-metastatic human melanoma cell line to become metastatic in a nude mouse system. To determine if MUC18 expression correlates with the development and malignant progression of prostate cancer, we investigated differential expression of human MUC18 (huMUC18) in normal prostate epithelial cells, prostate cancer cell lines, and prostatic normal and cancer tissues. We cloned and characterized the human MUC18 (huMUC18) cDNA gene from three human prostate cancer cell lines and three human melanoma cell lines. The cDNA sequences from the six human cancer cell lines were identical except differences in one to five nucleotides. The deduced amino acid sequences of the longest ORF were 646 amino acids that were identical in these cDNAs except for one to three amino acid residues. The amino acid sequences of all our huMUC18 cDNA genes are similar to that cloned by other group (GenBank access #M28882) except differences in the same seven amino acids. We conclude that huMUC18 cDNA gene reported here represents the gene product from a major allele. The MUC18 mRNA and protein was expressed in three metastatic prostate cancer cell lines (TSU-PR1, DU145, and PC-3), but not in one non-metastatic prostate cancer cell line (LNCaP.FGC). The expression of huMUC18 in these four cell lines is positively related to their extent of in vitro motility and invasiveness and in vivo metastasis in nude mice. HuMUC18 protein was also expressed at high levels in extracts prepared from tissue sample sections containing high grade prostatic intraepithelial neoplasia (PIN), but weakly expressed in extracts prepared from cultured primary normal prostatic epithelial cells and the normal prostate gland. Immunohistochemical analysis showed that huMUC18 was expressed at higher levels in the epithelial cells of high-grade PIN and prostatic carcinomas, and in cells of a perineural invasion, a lymph node, and a lung metastases compared to that in normal or benign hyperplastic epithelium (BPH). We therefore conclude that MUC18 expression is increased during prostate cancer initiation (high grade PIN) and progression to carcinoma, and in metastatic cell lines and metastatic carcinoma. Increased expression of MUC18 is implicated to play an important role in developing and malignant progression of human prostate cancer. Furthermore, the lacking of predominant cytoplasmic membrane expression of MUC18 appeared to correlate with malignant progression of prostate cancer.

[Influence of human cytomegalovirus infection on the expression of HOXB5, HOXB6, HOXB7, and HOXB8 genes in gliomaous cells]

OBJECTIVE

The expressions of HOXB5, HOXB6, HOXB7, and HOXB8 genes of U251 cell infected by human cytomegalovirus and/or treated with all trans-retinoic acid(ATRA) were detected by semi-quantitative RT-PCR. The results were that U251 cell did not express HOXB5, HOXB6, and HOXB8 but expressed HOXB7 without infecting HCMV and/or being treated with ATRA. After infected with HCMV and/or treated with ATRA, the expressions of HOXB7 and HOXB8 were up-regulated and the expression of HOXB7 lasted the fourth generation, while HOXB8 was up-regulated only in the second generation. These results indicate that the abnormal expression of HOXB gene induced by HCMV may play an important role in the maldevelopment.

Expression of a human cell adhesion molecule, MUC18, in prostate cancer cell lines and tissues

BACKGROUND

Over expression of huMUC18, a cell adhesion molecule in the immunoglobulin gene superfamily, causes a non-metastatic human melanoma cell line to become metastatic in a nude mouse system. To determine if MUC18 expression correlates with the malignant progression of prostate cancer, we investigated differential expression of human MUC18 (huMUC18) in normal prostate epithelial cells, prostate cancer cell lines, and prostatic normal and cancer tissues.

METHODS

RT-PCR and Western blot analyses were used to analyze the expression of MUC18 mRNA and protein in four human prostate cancer cell lines, cultured primary normal prostate epithelial cells, normal prostate and malignant prostate tissues. Immunohistochemistry was used to determine the expression of MUC18 antigen in prostatic tissues at different stages of malignancy.

RESULTS

Human MUC18 mRNA and protein was expressed in three different prostate cancer cell lines (TSU-PR1, DU145, and PC-3), but not in one prostate cancer cell line (LNCaP.FGC). HuMUC18 protein was also expressed at high levels in extracts prepared from tissue sample sections containing high grade prostatic intraepithelial neoplasia (PIN), but weakly expressed in extracts prepared from either cultured primary normal prostatic epithelial cells or the normal prostate gland. Immunohistochemical analysis showed that huMUC18 was expressed at higher levels in the epithelial cells of high-grade PIN and prostatic carcinomas and in cells of a lymph node metastasis compared to that in normal or benign hyperplastic epithelium (BPH).

CONCLUSIONS

We therefore conclude that MUC18 is expressed at higher levels in pre-malignant and malignant prostatic epithelium, including metastasis. We suggest that over-expression of MUC18 may be a new marker of human prostate cancer and also implicates its possible role in development and progression of prostate cancer.

Effects of propofol on mitochondrial function and intracellular calcium shift in bovine aortic endothelial model

BACKGROUND

Hypotension was commonly encountered in clinical practice during induction of anesthesia with propofol. The purpose of this study is to investigate the effect of propofol on mitochondrial membrane potential and morphology so as to infer its relation with intracellular calcium mobilization in bovine aortic endothelium.

METHODS

In this study, we used the cultured bovine aortic endothelial cells (Gm 7372a) to elucidate the impact of propofol upon the membrane potential and morphology of mitochondria in correlation with its effect on intracellular calcium shift. The intracellular calcium mobilization within the cells preincubated with or without propofol was evaluated using a fluorescent spectrophotometer (confocal microscope) after being treated with Fluo-3. The mobilization of intracellular calcium was demonstrated by the appearance of "hot spots" released from intracellular stores after the addition of an ionophore, ionomycin, to the incubation system. The membrane potential of mitochondria was measured by DiOC6 and the morphology of the mitochondria was evaluated by the treatment of TM Ros and compared with that by the treatment of the uncoupler, FCCP, as control.

RESULTS

The release of calcium "hot spots" from the intracellular stores (e.g. mitochondria) after the addition of ionomycin was visualized to decrease dramatically within the endothelial cells after preincubation with propofol. The membrane potential of mitochondria was significantly inhibited by pretreatment of propofol at 0.01 mM, 37 degrees C for 30 min. Morphologically, the integrity of mitochondria was distorted and fragmented in the presence of propofol as compared with that of control.

CONCLUSIONS

Our data showed that propofol in clinical concentration, 0.01 mM, could inhibit intracellular calcium shift from the intracellular stores and decrease the membrane potential and distort the morphology of mitochondria in bovine aortic endothelial cells. These inhibitions of the function and disfiguration of the morphology of mitochondria signify that the clinical hypotension induced by propofol might be of a potential mechanism.

[Listeria monocytogenes induces thymocyte apoptosis in mice]

The murine thymocyte apoptosis induced by Listeria monocytogenes(LM) was detected with morphology, FCM, and DNA electrophoresis. The results were that LM elicited typical morphological changes of thymocyte apoptosis; the typical apoptosis peak was displayed with FCM, and typical "ladder pattern" with agarose gel electrophoresis. The apoptotic cells were found at 8 h after the mice had infected LM and reached climax at 48 h. The thymus weight significantly reduced at 16 h, and reached the lowest at 48 h after the mice had infected LM. The percentage of apoptotic cells was raised with the increasing of LM. These results suggest that LM induces thymocyte apoptosis in dose- and time-dependent manner.

[The analgesic and antispasmodic effects of guang tong xiao aerosol of TCM]

OBJECTIVE

To observe the analgesic and antispasmodic effects of Guang Tong Xiao Aerosol (GTXA).

METHOD

Writhing test and tail-flick of physical stimulation were made to study the analgesic effect on mice and rats.

RESULT AND CONCLUSION

GTXA given by gastrogavage in dose of 18.75 g.kg-1 or 12.50 g.kg-1 could markedly raise the pain threshold after chemical stimulation in mice and physical stimulation in rats, and had antispasmodic effects.

[Influence of human cytomegalovirus infection on the expressions of HOXB1, HOXB5, HOXB6, and HOXB9 genes in human embryo lung cells]

OBJECTIVE

To study the expressions of HOXB1, HOXB5, HOXB6, and HOXB9 genes in human embryo lung (HEL) cells and influence of human cytomegalovirus (HCMV) infection on the expressions of these genes.

METHOD

The expressions of HOXB1, HOXB5, HOXB6, and HOXB9 genes were detected with semi-quantitative RT-PCR method.

RESULTS

1. HEL cells expressed HOXB5 and HOXB6 genes, but they did not express HOXB1 and HOXB9 genes. 2. After HCMV infection, HEL cell was induced to express HOXB9 gene, as the expression of HOXB6 gene was elevated. The expression of HOXB5 gene had no significant change. HOXB1 was still not expressed. 3. Treated with all-trans retinoic acid (ATRA), the expression of HOXB9 gene in HEL cells infected by HCMV was significantly increased. But during the advanced infect period, the expression of HOXB6 was significantly decreased.

CONCLUSION

HCMV can induce abnormal expressions of HOXB6 and HOXB9 genes, which may play an important role in HCMV-induced abnormal embryogenesis.

[Study on molecular epidemiology of HCMV infection in mothers and their newborns in Changsha]

The detection of HCMV-IgG, IgM in plasma by ELISA and DNA in plasma and P(C) BMCs from mothers and their newborns by PCR was carried out. Positive HCMV-IgG, HCMV-IgM, P(C)BMCs HCMV DNA and plasma HCMV DNA were demonstrated in 119(95.2%), 7(5.6%), 27(21.6%) and 14(11.2%) in 125 mothers and 117(93.6%), 1(0.8%), 18(14.4%) and 7(5.6%) in their mewborns, respectively. There were significant differences among the positive rate of newborn's HCMV-IgM, plasma HCMV DNA and CBMCs HCMV DNA (P < 0.05), but the difference between HCMV-IgM and plasma HCMV DNA had no statistic significance (P > 0.05). This study suggests that HCMV-IgG and CBMCs HCMV PCR are preferable epidemiological index of HCMV infection of pregnant women and newborns respectively.

Study of propofol in bovine aortic endothelium: I. Inhibitory effect on bradykinin-induced intracellular calcium immobilization

BACKGROUND

Propofol has been found to affect the intracellular calcium concentration with clinical manifestations of hypotension and bradycardia. The purpose of this study is to examine the effect of propofol on intracellular calcium immobilization in bovine aortic endothelium under the stimulation of bradykinin.

METHODS

In order to validate the effect of propofol on the alteration of intracellular calcium concentration, we used the cultured bovine endothelial cells (Gm 7372a) to measure the calcium immobilization within the cells preincubated with or without propofol of clinical concentration. Using Fluo-3 staining and a fluorescence spectrophotometer (confocal microscope), intracellular calcium immobilization was demonstrated by the appearance of "hot spots" within the cytoplasm and perinuclear regions after addition of bradykinin to the cells. The changes of fluorescence density measured within these areas versus the effect of time were analyzed and compared with the cells in control group.

RESULTS

After addition of bradykinin, intracellular calcium hot spots increased dramatically within seconds and reached a maximal level within 20 seconds. The concentrations of calcium gradually decreased to a constant level after about 3 min following the addition of bradykinin to the cells. With pretreatment of propofol at 0.01 mM and 37 degrees C for 30 min, the immobilization of intracellular calcium from the intracellular stores were significantly inhibited that was demonstrated by the decreased appearance of hot spots when compared with control.

CONCLUSIONS

Our data demonstrated that under the stimulation of bradykinin, propofol at 0.01 mM, could inhibit intracellular calcium release from the intracellular stores in bovine aortic endothelial cells. This phenomenon might explain the possible mechanism for the clinical manifestations of hypotension and/or bradycardia associated with propofol.

Effects of four methods of sperm preparation on motion characteristics and nitric oxide concentration in laboratory-prepared oligospermia

BACKGROUND

To compare four different spermatozoa preparation methods in semen samples with respect to recovery rate, percent motility, path and progressive velocity, and nitric oxide (NO) production before and after centrifugation.

METHODS

Each of 36 semen specimens was diluted to 1 x 10(6)/ml and divided into four 1-ml aliquots for sperm processing using four methods: swim-up, two (Percoll II) and three (Percoll III) layer Percoll (Pharmacia Biotech AB, Uppsala, Sweden) gradients and albumin columns. The motile sperm recovery rate, percent motility and motion parameters were measured for each semen specimen (n = 36) before and after processing using the four methods. NO was measured with the use of a chemiluminescence method before and after centrifugation (n = 17).

RESULTS

The sperm recovery rate was higher using both Percoll gradients than with the other two methods (Percoll II, 68 +/- 20.5%, Percoll III, 75.3 +/- 22.2% vs swim-up, 25.8 +/- 9.9% and albumin, 33.1 +/- 20.7%). The results were similar for total motile cells (Percoll II, 3.55 +/- 1.72 x 10(6)/ml, Percoll III, 4.25 +/- 1.29 x 10(6)/ml vs swim-up, 1.19 +/- 0.71 x 10(6)/ml and albumin, 1.89 +/- 1.36 x 10(6)/ml). Both Percoll methods and the albumin method produced a statistically significant improvement over the swim-up method in motility. The albumin column method resulted in the least path and progressive velocities (51.3 +/- 15.4 microns/s and 46.2 +/- 16.5 microns/s, respectively). NO produced during sperm processing did not differ significantly among the four processing methods (swim-up, 4,531 +/- 1,626 nM, Percoll II, 5,119 +/- 3,969 nM, Percoll III, 6,060 +/- 5,512 nM, albumin 4,838 +/- 2,462 nM).

CONCLUSIONS

Our data suggest that Percoll methods are superior to swim-up and albumin columns for sperm preparation, yielding good sperm recovery, motility and motion characteristics. The trend toward lower NO levels among samples prepared using albumin columns did not reach statistical significance.

The cytotoxicity of corrosion products of nitinol stent wire on cultured smooth muscle cells

Although nitinol is one of most popular materials of intravascular stents, there are still few confirmative biocompatibility data available, especially in vascular smooth muscle cells. In this report, the nitinol wires were corroded in Dulbecco's modified Eagle's medium with constant electrochemical breakdown voltage and the supernatant and precipitates of corrosion products were prepared as culture media. The dose and time effects of different concentrations of corrosion products on the growth and morphology of smooth muscle cells were evaluated with [(3)H]-thymidine uptake ratio and cell cycle sorter. Both the supernatant and precipitate of the corrosive products of nitinol wire were toxic to the primary cultured rat aortic smooth muscle cells. The growth inhibition was correlated well with the increased concentrations of the corrosion products. Although small stimulation was found with released nickel concentration of 0.95 +/- 0.23 ppm, the growth inhibition became significant when the nickel concentration was above 9 ppm. The corrosion products also altered cell morphology, induced cell necrosis, and decreased cell numbers. The cell replication was inhibited at the G0-G1 to S transition phase. This was the first study to demonstrate the cytotoxicity of corrosion products of current nitinol stent wire on smooth muscle cells, which might affect the postimplantation neointimal hyperplasia and the patency rate of cardiovascular stents.

[Influence of human cytomegalovirus infection on the expression of HOX genes in human embryo lung cells]

The expressions of HOX genes in human embryo lung (HEL) cells were detected with semi-quantitative RT-PCR method. The results were that HEL cells expressed HOXB7 gene and its expression increased after human cytomegalovirus (HCMV) infection. The level of expression reached maximum at 48 h after HCMV infection. Treated with all-trans retinoic acid (ATRA), the expression of HOXB7 in HEL cells infected by HCMV was significantly increased. The results suggest that the abnormal expression of HOX genes induced by HCMV might possibly play a role in virus-induced abnormal embryogenesis.

17q23 amplifications in breast cancer involve the PAT1, RAD51C, PS6K, and SIGma1B genes

Amplification of the 17q23 region occurs frequently in breast tumors. To characterize the structure of 17q23 amplicons and to identify oncogene targets associated with this alteration, we performed a copy number analysis of 87 17q23 localized expressed sequence tags in seven breast cancer cell lines. Three major regions of amplification were detected in the MCF7 and BT474 cell lines. Amplification of at least one of four known genes (PAT1, PS6K, RAD51C, and SIGMA1B) was detected in the cell lines and in 28% of 94 breast tumors. In most cases, these four genes were overexpressed when amplified, but there was a particularly good association between amplification of the SIGMA1B gene and elevated expression in tumors, which suggested a possible role for this gene in tumor progression. Our data show that this region contains at least four independent targets of amplification, which suggests that there is considerable variability in the structure of the 17q23 amplicon.

[Investigation of the effects of biotic field of plant seedling on human body]

In this paper we investigated the effects on human bodies after being placed in the Jiang's guideti cabin with biotic field to receive the plant seedlings' irradiating biological electromagnetic waves. The results found that the erythrocyte membrane permeability and fragidity were decreased, its tenacity increased, the secretion of thyroid and sexual hormones increased, the immune function enhanced and there was no significant alteration of the adrenal cortical hormone secretion. It is suggested that the electromagnetic wave from the plant seedlings is beneficial to the erythrocyte function, improves the metabolism, enhances the adolescent activities, improves sexual activity and enhances immune function, thus it is effective to health care and rejuvenation.

The cardiomyopathy and lens cataract mutation in alphaB-crystallin alters its protein structure, chaperone activity, and interaction with intermediate filaments in vitro

Desmin-related myopathy and cataract are both caused by the R120G mutation in alphaB-crystallin. Desmin-related myopathy is one of several diseases characterized by the coaggregation of intermediate filaments with alphaB-crystallin, and it identifies intermediate filaments as important physiological substrates for alphaB-crystallin. Using recombinant human alphaB-crystallin, the effects of the disease-causing mutation R120G upon the structure and the chaperone activities of alphaB-crystallin are reported. The secondary, tertiary, and quaternary structural features of alphaB-crystallin are all altered by the mutation as deduced by near- and far-UV circular dichroism spectroscopy, size exclusion chromatography, and chymotryptic digestion assays. The R120G alphaB-crystallin is also less stable than wild type alphaB-crystallin to heat-induced denaturation. These structural changes coincide with a significant reduction in the in vitro chaperone activity of the mutant alphaB-crystallin protein, as assessed by temperature-induced protein aggregation assays. The mutation also significantly altered the interaction of alphaB-crystallin with intermediate filaments. It abolished the ability of alphaB-crystallin to prevent those filament-filament interactions required to induce gel formation while increasing alphaB-crystallin binding to assembled intermediate filaments. These activities are closely correlated to the observed disease pathologies characterized by filament aggregation accompanied by alphaB-crystallin binding. These studies provide important insight into the mechanism of alphaB-crystallin-induced aggregation of intermediate filaments that causes disease.

Identification of core sequences involved in metabolism-dependent nuclear protein binding to the rat insulin-like growth factor I gene

In the liver, most insulin-like growth factor I (IGF-I) transcripts originate in exon 1, where important cis-regulatory regions are located downstream from the major transcription initiation sites. Within these regions, we have attempted to identify sequences which are involved in the decrease in IGF-I gene transcription associated with diabetes mellitus. The function of different genomic templates was assessed by in vitro transcription, which revealed a consistent 50-80% decrease in the activity of nuclear extracts from streptozotocin-diabetic as compared with normal rats. The disparity in transcriptional activity between normal and diabetic nuclear extracts was reduced with templates containing 11-bp mutations within DNase I protected regions III or V (+42 and +129 bp, respectively, from the major transcription initiation site), but a mutation between regions IV and V had little effect. Within region III, gel mobility shift analysis and methylation interference studies indicated that DNA-protein interactions involve a GCGC core sequence. In region V, gel mobility shift studies and uracil interference analysis revealed interactions involving a TTAT core. While gel mobility shift analysis and transient transfection studies indicate that the GCGC core sequence in region III recognizes C/EBP, the AT-rich sequence in region V is likely to recognize a protein with homeodomain characteristics. Identification of the nuclear factor(s) interacting with regions III and V, downstream from exon 1 initiation sites, will be important for understanding the mechanism of reduced IGF-I gene transcription due to diabetes mellitus.

Site-directed mutations within the core "alpha-crystallin" domain of the small heat-shock protein, human alphaB-crystallin, decrease molecular chaperone functions

Site-directed mutagenesis was used to evaluate the effects on structure and function of selected substitutions within and N-terminal to the core "alpha-crystallin" domain of the small heat-shock protein (sHsp) and molecular chaperone, human alphaB-crystallin. Five alphaB-crystallin mutants containing single amino acid substitutions within the core alpha-crystallin domain displayed a modest decrease in chaperone activity in aggregation assays in vitro and in protecting cell viability of E. coli at 50 degrees C in vivo. In contrast, seven alphaB-crystallin mutants containing substitutions N-terminal to the core alpha-crystallin domain generally resembled wild-type alphaB-crystallin in chaperone activity in vitro and in vivo. Size-exclusion chromatography, ultraviolet circular dichroism spectroscopy and limited proteolysis were used to evaluate potential structural changes in the 12 alphaB-crystallin mutants. The secondary, tertiary and quaternary structures of mutants within and N-terminal to the core alpha-crystallin domain were similar to wild-type alphaB-crystallin. SDS-PAGE patterns of chymotryptic digestion were also similar in the mutant and wild-type proteins, indicating that the mutations did not introduce structural modifications that altered the exposure of proteolytic cleavage sites in alphaB-crystallin. On the basis of the similarities between the sequences of human alphaB-crystallin and the sHsp Mj HSP16.5, the only sHsp for which there exists high resolution structural information, a three-dimensional model for alphaB-crystallin was constructed. The mutations at sites within the core alpha-crystallin domain of alphaB-crystallin identify regions that may be important for the molecular chaperone functions of sHsps.

Localization of PS6K to chromosomal region 17q23 and determination of its amplification in breast cancer

The application of comparative genomic hybridization to the analysis of genetic abnormalities in breast carcinoma has consistently revealed that chromosome region 17q22-24 is a frequent site of gene amplification in this type of cancer. As part of an examination of expressed sequence tags for novel amplified genes in this region, we identified PS6K amplifications in both breast tumor tissues and cell lines. PS6K was localized to 17q23 and encodes a serine-threonine kinase whose activation is thought to regulate a wide array of cellular processes involved in the mitogenic response including protein synthesis, translation of specific mRNA species, and cell cycle progression from G1 to S phase. Northern and Western analyses revealed that amplification of this gene was accompanied by corresponding increases in mRNA and protein expression, respectively. These data represent the first determination of a gene amplification within 17q22-24 in breast cancer and suggest an oncogenic activity for PS6K.

[Opioid mu receptors in caudate nucleus contribute to electroacupuncture and Sm I generating inhibition on nociceptive responses of Pf neurons]

The present experiments aimed to investigate whether the caudate nucleus (Cd) was involved in cortical sensorimotor area I (Sm I) generating descending modulation of the parafascicular nucleus (Pf) in acupuncture analgesia (AA), and what type of opiate receptors in Cd were involved. It was found that nociceptive responses of Pf neurons could be inhibited by electroacupuncture (EA) and excitation of Sm I before lesion of Cd, but not after lesion. After microinjection of naloxone beta-FNA, the specific antagonist for opioid mu receptors, into Cd,the inhibitory effect of EA or activation of Sm I on nociceptive responses of the Pf neurons was abolished, but it was not influenced by microinjection of nor-BNI and ICI174,864, the specific antagonists for opioid kappa and delta receptors, respectively. Together with our previous findings that EA could activate cortical neurons to participate in descending modulation of activities of Pf neurons, the present results suggest that Cd is associated with Sm I generating descending inhibition on nociceptive responses of Pf neurons in AA, and it is most likely that opiates in Cd may be involved in this inhibition through mu but not kappa or delta receptors.

[Isolation of novel expression sequences of C2H2 type zinc finger protein gene from human brain tissue according to the conservation of zinc finger motif]

By low stringency PCR amplification of genomic DNA using the primers designed based on the conservation of zinc finger motif, we got 8 gradient eletrophoretic bands. After recovery of the second and third bands, the DNA fragments in them were cloned and sequenced. Compared to the GenBank database, among these 60 segments containing zinc finger motif, 23 segments were novel zinc finger genes' genomic segments. Then the human brain tissue cDNA library was screened, using these segments as probes, and 44 positive clones were obtained. Rescreening 28 of them, we got 20 rescreened clones. All of them were sequenced and sent to the GenBank DNA database for sequence analysis, the results showed that 16 were novel C2H2 type zinc finger protein cDNA segments. The cDNA segments encoding the novel C2H2 type zinc finger proteins provide the basic materials for cloning of full length cDNA of valuable novel zinc finger protein genes.