Compensatory PI3-kinase/Akt/mTor activation regulates imatinib resistance development

BCR/ABL-kinase mutations frequently mediate clinical resistance to the selective tyrosine kinase inhibitor Imatinib mesylate (IM, Gleevec). However, mechanisms that promote survival of BCR/ABL-positive cells before clinically overt IM resistance occurs have poorly been defined so far. Here, we demonstrate that IM-treatment activated the phosphatidylinositol 3-kinase (PI3K)/Akt/mammalian target of rapamycin (mTor)-pathway in BCR/ABL-positive LAMA-cells and primary leukemia cells in vitro, as well as in a chronic phase CML patient in vivo. In fact, PI3K/Akt-activation critically mediated survival during the early phase of IM resistance development before manifestation of BCR/ABL-dependent strong IM resistance such as through a kinase mutation. Accordingly, inhibition of IM-induced Akt activation using mTor inhibitors and Akt-specific siRNA effectively antagonized development of incipient IM-resistance in vitro. In contrast, IM-resistant chronic myeloid leukemia (CML) patients with BCR/ABL kinase mutations (n=15), and IM-refractory BCR/ABL-positive acute lymphatic leukemia patients (n=2) displayed inconsistent and kinase mutation-independent autonomous patterns of Akt-pathway activation, and mTor-inhibition overcame IM resistance only if Akt was strongly activated. Together, an IM-induced compensatory Akt/mTor activation may represent a novel mechanism for the persistence of BCR/ABL-positive cells in IM-treated patients. Treatment with mTor inhibitors may thus be particularly effective in IM-sensitive patients, whereas Akt-pathway activation variably contributes to clinically overt IM resistance.

Growth mechanism and ultraviolet-light emission of the self-assembled complex of MgO nanostructures

Bulk-quantity net-like nanodendrites and four-fold hierarchical nanostructures were synthesized by direct thermal evaporation and oxidation of metallic Mg powder. Their formation mechanism is explained using the self-catalytic vapor-liquid-solid mechanism together with dendritic-crystal epitaxial growth mechanism. Four-branch and eight-branch nanodendrites were also detected. The photoluminescence spectrum reveals that the peak with the maximum intensity is centered at about 3.16 eV (392 nm). Through Gaussian fitting, a strong and narrow ultraviolet-light emission peak centered at 3.16 eV (392 nm) and a relatively weak but broad blue-light emission band centered at 2.74 eV (453 nm) were observed in the photoluminescence emission spectrum, which are respectively attributed to the recombination luminescence of the F+ and F centers (belonging to oxygen-vacancy related defect levels) in the MgO nanostructures. In addition, another very weak and broad red-infrared emission band can also be detected, which is probably due to the relaxation luminescence of impurity levels in the MgO nanostructures.

Older adults' trait ratings of three age-groups around the Pacific rim

In this paper, we assess the traits that older adults associate with younger, middle-aged, and older adults in five Pacific Rim nations from Western and Eastern cultural traditions (Australia, People's Republic of China (PRC), Hong Kong, Philippines, Thailand). We find cross-cultural trends which replicate patterns found in the US context. In most cultures, attractiveness, strength, activity, liberalism, health, and flexibility are seen to decline with increasing age. Kindness assessments are positively associated with age across cultures. Mixed patterns are found with assessments of wisdom and generosity, with respondents from the PRC and Hong Kong being notably more negative about increasing age than other respondents. Implications for the aging process across cultures are discussed, and suggestions made for future research.

Mechanistic aspects of chiral discrimination on an amylose tris(3,5-dimethylphenyl)carbamate

The separation of [2R-[2alpha(R*),3alpha]]-5-[[2-[1-[3,5-bis-(trifluoromethyl)phenyl]ethoxy]-3(S)-4-fluorophenyl)4-morpholinyl]-methyl]-N,N-dimethyl-1H-1,2,3-triazole-4-methanamine hydrochloride from its enantiomer was achieved on an amylose tris-3,5-dimethylphenyl carbamate stationary phase. The retention of the enantiomers is dominated by weak hydrogen bonds while the enantioselectivity is governed by other kinds of interactions, e.g., inclusion in the amylose carbamate chains. Van't Hoffplots of 1nalpha vs. reciprocal temperature were non-linear and could be divided into two linear regions. One region at low temperature (5 degrees C- approximately 20 degrees C) and another one between 25 degrees C-70 degrees C with the change in slope occurring between 16 degrees C and 20 degrees C. DSC experiments suggested that the behavior can be attributed to breakage of H-bonds triggering a conformational change. Molecular simulation indicated a correlation between the interaction energies and the elution order obtained experimentally. The most retained enantiomer (R,R,S-enantiomer) interacts with the stationary phase through a hydrogen bond between the triazole proton and the C=O groups of the stationary phase, as well as through an inclusion in the cleft of the stationary phase. The other enantiomer exhibits a bifurcated H-bond between the triazolic proton and the C=O groups of the stationary phase leading to a less stable complex.

Pigeon allergens in indoor environments: a preliminary study

BACKGROUND

Few studies have measured pigeon allergens in non pigeon coop environments. This study was conducted to determine approximate pigeon dropping allergen concentrations in indoor environments.

METHODS

Polyclonal antibody serum was prepared by injecting a rabbit three times with crude wild pigeon dropping extract in 50 mM Tris buffer with Freund's adjuvant. One hundred and fifteen dust samples were collected in a pigeon-infested school, pigeon coops, homes and hospitals and analyzed by a direct competitive pigeon enzyme-linked immunosorbent assay (ELISA).

RESULTS

The highest level of pigeon allergen inhibitory activity were recorded in four samples from pigeon coop bedding samples with a median activity of 11.2% relative to pigeon droppings. The second highest level of pigeon allergens was in a pigeon-infested high school with a median or 7.4% activity relative to pigeon droppings. At an entrance underneath pigeon roosts, one sample had a relative inhibitory activity of 62.3%. Pigeon allergen inhibitory levels were generally low in the home and hospital samples, but nevertheless 46 out of 89 of these samples were still above detection limit.

CONCLUSIONS

This study suggests that large concentrations of pigeon allergens can be found in buildings without domestic pigeons such as the pigeon-infested high school.

Lapine and canine bone marrow stromal cells contain smooth muscle actin and contract a collagen-glycosaminoglycan matrix

Lapine and canine marrow stromal cells were found to contain a contractile actin isoform, alpha-smooth muscle actin (SMA), by immunohistochemistry and Western blot analysis. The SMA was found to be incorporated into stress fibers that were prominently displayed by the cells in monolayer culture. The cell content of this actin isoform increased with passage number. The contractility of SMA-expressing stromal cells was demonstrated by their contraction of collagen-glycosaminoglycan analogs of extracellular matrix into which they were seeded. The demonstration that marrow-derived stromal cells express the SMA gene may explain recent findings of this expression in musculoskeletal connective tissue cells including osteoblasts, chondrocytes, and fibrochondrocytes that may be derived from this mesenchymal stem cell. The implications of these findings for tissue engineering strategies employing marrow stromal cells are also discussed.

Deletion of the NF2 region in both meningioma and juxtaposed meningioangiomatosis: case report supporting a neoplastic relationship

We report a case of juxtaposed atypical meningioma and meningioangiomatosis (MA) in an 8-year-old boy with no clinical stigmata or family history of neurofibromatosis. We studied the proliferative activity and genetic changes in the two lesions in an attempt to define their biologic and pathogenetic relationships. The MIB-1 index was 11% in the meningioma and <1% in the MA, indicating increased proliferative activity in the meningioma. Fluorescence in situ hybridization was done for two chromosomal regions commonly deleted in meningiomas. There was loss of the neurofibromatosis 2 locus (22q12) in both the meningioma and MA. Conversely, the region of 1p32 was not deleted. Our results indicate that both the meningioma and MA arose from the same clonal process, with the meningioma probably undergoing additional, but undefined, genetic alterations that confer upon it a more proliferative potential. This loss of 22q12 in the MA raises doubt about the presumed hamartomatous nature of MA.

Mechanisms for increased levels of phosphorylation of elongation factor-2 during hibernation in ground squirrels

Previously, eEF-2 phosphorylation has been identified as a reversible mechanism involved in the inhibition of the elongation phase of translation. In this study, an increased level of phosphorylation of eukaryotic elongation factor-2 (eEF-2) was observed in the brains and livers of hibernating ground squirrels. In brain and liver from hibernators, eEF-2 kinase activity was increased relative to that of active animals. The activity of protein phosphatase 2A (PP2A), a phosphatase that dephosphorylates eEF-2, was also decreased in brain and liver from hibernators. This was associated with an increase in the level of inhibitor 2 of PP2A (I(2)(PP2A)), although there was an increase in the level of the catalytic subunit of PP2A (PP2A/C) in hibernating brains and livers. These results indicate that eEF-2 phosphorylation represents a specific and previously uncharacterized mechanism for inhibition of the elongation phase of protein synthesis during hibernation. Increased levels of eEF-2 phosphorylation in hibernators appear to be a component of the regulated shutdown of cellular functions that permits hibernating animals to tolerate severe reductions in cerebral blood flow and oxygen delivery capacity.

Mechanisms of multiple organ damages in acute necrotizing pancreatitis

OBJECTIVE

To determine the role of systemic inflammatory response syndrome (SIRS) and multiple organ dysfunction syndrome (MODS), and evaluate the progress from SIRS to MODS and the therapeutic strategies for acute necrotizing pancreatitis (ANP).

METHODS

Rat ANP models were made by retrograde injection of 3.5% sodium taurocholate 2.5 ml/kg into the pancreatic duct. Serum interleukin-8 (IL-8), interleukin-6 (IL-6), interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF alpha), amylase, endotoxin, and albumin were examined. The morphology and pathology of the pancreas, liver, lung, kidney and heart after ANP were observed. Finally, TNF alpha mRNA in the liver, lung, kidney and heart after ANP were observed by reverse transcriptase-polymerase chain reactions, and the efficiency of somatostatin and growth hormone were also observed in this experiment.

RESULTS

ANP led to remarkable elevation of the inflammatory mediators which were positively correlated with the development of ANP and MODS. Somatostatin and growth hormone inhibited inflammatory mediators and TNF alpha mRNA overexpressions, reduced the risk of MODS, corrected hypoalbuminemia, reversed negative nitrogen balance, and controlled the reduction of cell groups with functions and reasonably intervened SIRS caused by ANP.

CONCLUSION

TNF alpha mRNA plays an important role in ANP progression. The amelioration of ANP by combination treatment with somatostatin and growth hormone leads to the reduction of complications and marked increase in survival.

Neuronal cyclic AMP controls the developmental loss in ability of axons to regenerate

Unlike neonatal axons, mammalian adult axons do not regenerate after injury. Likewise, myelin, a major factor in preventing regeneration in the adult, inhibits regeneration from older but not younger neurons. Identification of the molecular events responsible for this developmental loss of regenerative capacity is believed key to devising strategies to encourage regeneration in adults after injury. Here, we report that the endogenous levels of the cyclic nucleotide, cAMP, are dramatically higher in young neurons in which axonal growth is promoted both by myelin in general and by a specific myelin component, myelin-associated glycoprotein (MAG), than in the same types of neurons that, when older, are inhibited by myelin-MAG. Inhibiting a downstream effector of cAMP [protein kinase A (PKA)] prevents myelin-MAG promotion from young neurons, and elevating cAMP blocks myelin-MAG inhibition of neurite outgrowth in older neurons. Importantly, developmental plasticity of spinal tract axons in neonatal rat pups in vivo is dramatically reduced by inhibition of PKA. Thus, the switch from promotion to inhibition by myelin-MAG, which marks the developmental loss of regenerative capacity, is mediated by a developmentally regulated decrease in endogenous neuronal cAMP levels.

Reaction kinetics of protease with substrate phage. Kinetic model developed using stromelysin

Peptide libraries generated using phage display have been widely applied to proteolytic enzymes for substrate selection and optimization, but the reaction kinetics between the enzyme and substrate phage are not well understood. Using a quantitative ELISA assay to monitor the disappearance of substrate, we have been able to follow the course of reaction between stromelysin, a metalloprotease, and its substrate phage. We found that under the proteolytic conditions where the enzyme was present in nanomolar concentration or higher, in excess over the substrate, the proteolysis of substrate phage was a single exponential event and the observed rate linear with respect to enzyme concentration. The enzyme concentration dependence could be described by pseudo first-order kinetic equations. Our data suggest that substrate binding is slow relative to the subsequent hydrolysis step, implying that the phage display selection process enriches clones that have high binding affinity to the protease, and the selection may not discriminate those of different chemical reactivity toward the enzyme. Considering that multiple substrate molecules may be present on a single phage particle, we regard the substrate phage reaction kinetic model as empirical. The validity of the model was ascertained when we successfully applied it to determine the binding affinity of a competitive inhibitor of stromelysin.

Primary studies on heroin abuse and injury induced by oxidation and lipoperoxidation

OBJECTIVE

To further reveal serious risks of heroin abuse to human body and clarify grave injuries of oxidation, peroxidation and lipoperoxidation induced by nitric oxide and other free radicals to heroin abusers.

METHODS

Determined and compared plasma levels of nitric oxide (P-NO), vitamin C (P-VC), vitamin E (P-VE), beta-carotene (P-beta-CAR), lipoperoxides (P-LPO) and erythrocyte activities of superoxide dismutase (E-SOD), catalase (E-CAT), glutathione peroxidase (E-GSH-Px) and erythrocyte level of lipoperoxides (E-LPO) in 137 cases of heroin abusers (HAs) and 100 cases of healthy volunteers (HVs), used linear regression and correlation, stepwise regression and correlation to analyze correlation among heroin-abusing-duration (HAD), daily-heroin-abusing-quantity (DHAQ) with above determination values in the HAs.

RESULTS

Compared with the above average values in the HVs group, the average values of P-NO, P-LPO, E-LPO in the HAs group were significantly increased (P < 0.0001), the average values of P-VC, P-VE, P-beta-CAR, E-SOD, E-CAT and E-GSH-Px were significantly decreased (P < 0.0001); the analysis of linear regression and correlation showed that with ascending of the HAD and DHAQ in the HAs, the values of P-NO, P-LPO, E-LPO were gradually increased (P < 0.0001), the values of P-VC, P-VE, P-beta-CAR, E-SOD, E-CAT, E-GSH-Px were gradually decreased (P < 0.0001); the analysis of stepwise regression and correlation suggested that the correlation among the HAD, DHAQ with the values of P-NO, P-VC, P-VE was the closest.

CONCLUSION

The balance between oxidation and antioxidation in the HAs was seriously destroyed, and the injuries induced by nitric oxide and other free radicals, oxidation, peroxidation and lipoperoxidation reactions to the body of HAs gravely exacerbated. In the abstaining from heroin dependence, therefore, it should consider that sufficient quantum antioxidants such as VC, VE and beta-CAR are dosed to the HAs so as to abate the injuries to their bodies.

High-resolution mapping of YACs and the single-copy gene Hs1(pro-1) on Beta vulgaris chromosomes by multi-colour fluorescence in situ hybridization

Fluorescence in situ hybridization (FISH) is a powerful approach for physical mapping of DNA sequences along plant chromosomes. Nematode-resistant sugar beets (Beta vulgaris) carrying a Beta procumbens translocation were investigated by FISH with two differentially labelled YACs originating from the translocation. At mitotic metaphases, the translocation was identified with both YACs in the terminal region on a pair of chromosomes. Meiotic chromosomes, representing a far more extended hybridization target, were used to determine the orientation of YACs with respect to chromosomal domains in combination with chromosomal landmark probes for telomeres and centromeres. The in situ detection of plant single-copy sequences is technically difficult, and the wild beet translocation was used to explore the potential resolution of the FISH approach and to introduce the chromosomal mapping of single-copy genes into genome analysis of Beta species. An internal fragment of the nematode resistance gene Hs1(pro-1), 684 bp long, was detected on both chromatids of different Beta chromosomes and represents one of the shortest unique DNA sequences localized on mitotic plant chromosomes so far. Comparative chromosomal mapping of the 684 bp Hs1(pro-1) probe in the translocation line, a monosomic addition line and in B. procumbens revealed the origin of the wild beet translocation leading to nematode-resistant sugar beets.

Identification and Purification of an Intrinsic Human Muscle Myogenic Factor That Enhances Muscle Repair and Regeneration

The limited ability of damaged muscle to regenerate after gross injuries is a major clinical problem. To date, there is no effective therapeutic treatment for muscle injuries. In the present study, we have examined the ability of crude and fractionated human skeletal muscle extracts to promote myogenic cell proliferation and differentiation. It was found that the crude muscle extract could significantly stimulate BrdU incorporation in C2C12 myogenic cell line. In addition, the extract also promoted myogenic cell alignment and fusion. Using electrophoresis techniques, in conjunction with in vitro refolding technique, a protein with molecular weight of approximately 40 kDa was identified that could produce the same effects as the crude muscle exdtract. We also tested the ability of semipurified (30-50 kDa) muscle extract to promote muscle repair in adult rats. Surgical intervention was used to induce muscle damage in the tibialis anterior. The semipurified muscle extract (fraction H) was injected subcutaneously over the tibialis anterior for a period of 5 days. It was found that the damaged muscle fibers were replaced by newly regenerated muscle fibers. These newly regenerated fibers originated from the fusion of differentiated satellite cells as revealed by BrdU-labeling analysis. In contrast, the injury site of muscles treated with BSA control protein contained mainly fibroblasts.

[Effects of yanggan xifeng recipe on changes of neurological behavior of rat of Parkinson's model]

OBJECTIVE

To investigate the effect of Yanggan Xifeng Recipe (YGXFR) for nourishing Liver to calm down endogenous Wind on neurological behavior of Parkinson's disease (PD) rat model.

METHODS

PD rat model was established by destroying the substantia nigra condense area (SNc) and ventral tegmental area (VTA) unilaterally with 6-hydroxy dopamine (6-OHDA). The rats for control were injected in the same site with the same dose of normal saline. The animals were randomly divided into 3 groups (7 in each group), the control group, the model group and the TCM treated group. Staircase test and rotation test induced by apomorphine were performed in all groups and compared.

RESULTS

The staircase test demonstrated that, after being treated with YGXFR, the food pellets intake were increased compared to model group (P < 0.05), and their rotation induced by apomorphine was lessened (P < 0.01).

CONCLUSION

YGXFR could recover the neurological behavior deficits of PD rat models.

[Analyses on the association of CA-repeat polymorphism and A1166-->C variant in the 3'-flanking region of AT(1)R gene with essential hypertension in Tibetans]

OBJECTIVE

To investigate whether CA-repeat polymorphism and A1166 --> C variant in the 3n-flanking region of AT(1)R gene are in association with the genetic susceptibily to essential hypertension (EH) in Tibetans.

METHODS

A case-control study was carried out. Sibpair analysis and family linkage analysis were conducted. The CA-repeat polymorphism of AT &(1) R gene was identified by polymerase chain reaction(PCR) with fluorescence labeled dCTP as substrate and by semi-automatic sequence technology. The A1166 -->C variant was detected by PCR-RFLP.

RESULTS

Association of AT&(1)R gene locus with EH was confirmed through the case-control study in well-characterized group of 113 Tibetan EH patients and 131 normotensives(chi(2)=26.44, P<0.001). A closer examination of this gene locus found 11 alleles from Tibetan population; allele A7 (138 bp) was more frequent in both the patients and the controls. Allele A8(140 bp) was in strong positive association with genetic susceptibility to EH in Tibetans. Frequency of allele A8 was 20.5% in EH and 7.3% in normotensives. The difference of allele frequencies between the groups was significant (chi(2)=9.64, P=0.002, OR=3.46, 95% CI 1.44-8.51). Affected sibpair analysis showed chi(2)=3.85, P=0.025; family linkage analysis gave Lod score of 0.80. No association between A1166 --> C variant in AT(1)R gene and EH in Tibetans was observed (P>0.05).

CONCLUSION

The result suggests that CA-repeat polymorphism of AT(1)R gene be in association with EH in Tibetans, which implicates that AT(1)R gene may be in linkage disequilibrium with the causative genes of EH.

Photoelectrochemistry as a novel strategy for DNA hybridization detection

The special properties of ssDNA and dsDNA molecules in structure and electric behavior, may offer us some new ideas for the fabrication of genosensors and DNA-chips. In this work, the photoelectrochemical method was firstly employed to characterize the photoelectric behavior of a ssDNA probe electrode, which was prepared with the self-assembly technique, and its resulting dsDNA electrode. The obvious decrease in the photocurrent of the dsDNA modified electrode at open potential or a bias voltage indicated that photoelectrochemistry was another useful method for DNA hybridization detection. Using the special design of ssDNA probes, we attempt to discuss further the relationship between the properties of DNA molecules and their photoelectric behaviors. In addition, the electrochemical impedance method was employed to verify the occurrence of some modifications over the electrode interface before and after the hybridization event.

p130Cas regulates the activity of AND-34, a novel Ral, Rap1, and R-Ras guanine nucleotide exchange factor

We previously identified a novel murine protein, AND-34, with a carboxyl-terminal domain homologous to Ras family guanine nucleotide exchange factors (GEFs), which bound to the focal adhesion docking protein p130(Cas). Work by others has implicated both the human homologue of AND-34, BCAR3, and human p130(Cas), BCAR1, in the resistance of breast cancer cells to the anti-estrogen tamoxifen. Here we report that AND-34 displays GEF activity on RalA, Rap1A, and R-Ras but not Ha-Ras GTPases in cells. In contrast to several other Ral-GEFs, the Ral GEF activity of AND-34 is not augmented by constitutively active Ha-Ras(Val-12), consistent with the absence of a detectable Ras-binding domain. Efficient binding to AND-34 required both the Src-binding domain and a flanking carboxyl-terminal region of p130(Cas). The p130(Cas)-binding site mapped to a carboxyl-terminal sequence within the AND-34 GEF domain. Overexpression of p130(Cas), but not an AND-34-binding mutant of p130(Cas), inhibited the Ral GEF activity of co-transfected AND-34. This work identifies a new potential function for p130(Cas) and a new regulatory pathway involved in the control of Ral, Rap, and R-Ras GTPases that may participate in the progression of breast cancer cells to tamoxifen resistance.

[Protective effect of Ginaton on rat liver microcirculation disturbance following liver xenotransplantation]

OBJECTIVE

To study the effect of Ginaton on liver microcirculation disturbance following liver xenotransplantation in rats.

METHODS

Ginaton was injected intravenously to recipients at a dosage of 14 mg/kg before graftng liver of guinea pigs. The portal blood flow (PBF) was measured by Doppler ultrasound at 0, 30 and 60 minutes after transplantation, and the pathologic changes of liver and heart were observed.

RESULTS

The reperfusion status of control group was poor and leukocyte infiltration appeared in the center of lobute following transplantation and myocardial cells were impaired. Significant reduction in PBF was found in rats following transplantation. Ginaton pretreatment distinctly ameliorated PBF. The speed of PBF was closely correlated with the pathologic changes following transplantation.

CONCLUSION

In the process of liver transplantation, ischemia reperfusion damage may lead to xenoheptic microcirculaton disturbance. Ginaton could improve the xenoheptic microcirculation and reduce ischemic reperfusion damage.

Experimental study of the effect of external counterpulsation on blood circulation in the lower extremities

A bidirectional ultrasonic Doppler flowmeter with direct single sideband separation was used to measure blood flow in the femoral and dorsalis pedis arteries of 18 normal volunteers. Changes in blood-flow velocity and volume during external counterpulsation (ECP) with various sustaining times (the time for maintaining pressure) for inflation were studied. The results showed that blood-flow velocity in the femoral and dorsalis pedis arteries is increased significantly by ECP, but the change is not closely related to the duration of inflation. For a short sustaining time, the net forward blood-flow volume in arteries increased remarkably, but at longer sustaining times it dropped back significantly to a value even lower than that before ECP. The sustaining time for inflation to produce the maximum net forward flow volume (the optimal sustaining time of inflation) was found to be at one-quarter to one-third of the cardiac cycle. In a second study, changes in the calibre of the femoral artery and its collateral and anastomotic branches in the hind extremities in 5 dogs before and after ECP with an optimal sustaining time of inflation were examined by femoral arteriography. The experiments showed that the patency of collateral and anastomotic branches of the femoral artery was greater before than after ECP. The study suggests that ECP could be an effective treatment for improving the blood circulation in extremities.

Heroin abuse and nitric oxide, oxidation, peroxidation, lipoperoxidation

To further reveal the risks of heroin abuse to human body, and to determine the injuries of oxidation, peroxidation and lipoperoxidation induced by nitric oxide and other free radicals to heroin abusers, we determined and compared plasma values of lipoperoxides (LPO), nitric oxide (NO), vitamin C (VC), vitamin E (VE), beta-carotene (beta-CAR) and erythrocyte values of LPO, superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GSH-Px) in 114 heroin abusers and 100 healthy volunteers. Using linear regression and correlation as well as stepwise regression and correlation, we also analyzed the effect of the abusing duration, and daily abusing quantity on the above-mentioned biochemical parameters in the heroin abusers. The results showed that, compared with the healthy volunteer groups, the average plasma values of LPO, and NO, and the average erythrocyte value of LPO in the heroin abuser group were significantly increased (P < 0.0001), and the average plasma values of VC, VE, and beta-CAR and the average erythrocyte values of SOD, CAT, and GSH-Px were significantly decreased (P < 0.0001). Analysis of linear regression and correlation showed that with prolonged heroin abusing and with increased daily quantity in the heroin abusers, the plasma values of LPO, and NO, and the erythrocyte value of LPO were gradually increased (P < 0.001), whereas the plasma values of VC, VE, and beta-CAR and the erythrocyte values of SOD, CAT, and GSH-Px were gradually decreased (P < 0.001). Analysis of stepwise regression and correlation indicated that the plasma values of NO, VC and VE were closely correlated with the abusing duration and daily abusing quantity. These results indicate that the balance between oxidation and antioxidation in the heroin abusers was seriously disturbed, and the injuries induced by nitric oxide and other free radicals, through oxidation, peroxidation and lipoperoxidation to the bodies of heroin abusers exacerbated. It is therefore necessary that in abstaining from heroin dependence, the heroin abusers should acquire sufficient quantities of antioxidants such as VC, VE and beta-CAR.

Association analysis of variants in the core promoter region of angiotensinogen gene with essential hypertension in Tibetan population

OBJECTIVE

To detect the variants in the core promoter region of angiotensinogen(AGT) gene, and to analyse the relationship between the AGT gene polymorphisms and essential hypertension in Tibetan population.

METHODS

This is a case-control study consisting of 103 essential hypertensive subjects and 82 normotensive controls matched by age and sex. The variants in the AGT gene core promoter region were screened by polymerase chain reaction/single strand conformation polymorphism(PCR/SSCP) and further identified by automated sequencing. The A(-6)G polymorphism was determined in DNA extracted from leucocytes by polymerase chain reaction/restriction fragment length polymorphism (PCR/RFLP).

RESULTS

(1) There were two different electrophoresis band patterns in PCR/SSCP analysis. PCR product direct sequencing showed that the two band patterns represented the AA, AC genotypes in the (-20) site of AGT gene respectively. The distribution of A(-20)C genotype was almost identical in essential hypertensive and normotensive groups (P>0.8). The A allele frequency was very high in both groups (control: 0.9175, hypertensive: 0.9124). (2)Distribution of genotype in the (-6) site of AGT gene was much different between the patient group and control group (P<0.005). The frequency of G allele was statistically higher in the patient group than in controls (0.374 vs 0.220, P<0.025).

CONCLUSION

Both Tibetan hypertensives and normotensives have higher frequency of A allele in AGT gene (-20) site. The higher frequency of G allele in the AGT gene (-6) site in Tibetan hypertension patients suggests that this allele may be the genetic susceptibility factor in the proceeding of essential hypertension in the Tibetan population.

Effect of thyroid hormone deficiency on developmental expression of goalpha gene in the brain of neonatal rats by competitive RT-PCR and in situ hybridization histochemistry

Goalpha is a guanine nucloetide-binding regulatory protein alpha subunit which is mainly distributed in the central nervous system, but it has not previously been reported how it is regulated by thyroid hormone in the brain of neonatal rat at transcriptional levels. In this report, we used quantitative competitive reverse transcriptional PCR to quantify the effects of TH deficiency on Goalpha gene expression in the brain of neonatal rat at mRNA levels. It was found that Goalpha mRNA levels in the brain of 14-day-old rats significantly increased over 3-fold after induction of perinatal hypothyroidism, and declined markedly after treatment of thyroxine replacement. In situ hybridization histochemistry was further employed to observe the time-course and spatial expression of Goalpha gene in the brain of neonatal rats affected by thyroid hormone deficiency during the developmental period. The data showed that perinatal hypothyroidism can enhance Goalpha mRNA levels in the temporal cortex, sensorimotor cortex, piriform cortex, amygdala, hippocampal CA1-4 subfields, dentate gyrus, arcuate nucleus (AR) and ventromedial hypothalamic nucleus (VMH) of hypothalamus, but not in the striate cortex, cingulate cortex, claustrum, caudate/putamen and thalamus in the brain of rat at 7-21 days post-partum. The results suggest that up-regulation of Goalpha gene expression may be one kind of common mechanism responsible for neurological deficits in some brain areas arising from thyroid hormone deficiency in the critical periods of neonatal rats.