Metallothionein-I/II knockout mice are sensitive to acetaminophen-induced hepatotoxicity

The purpose of this study was to examine whether intracellular metallothionein (MT) protects against acetaminophen hepatotoxicity. MT-I/II knockout (MT-null) and control mice were given acetaminophen (150-500 mg/kg i.p.), and liver injury was assessed 24 h later. MT-null mice were more susceptible than controls to acetaminophen-induced lethality and hepatotoxicity, as evidenced by elevated serum enzyme activities and histopathology. Zinc pretreatment, a method of MT induction, protected against acetaminophen hepatotoxicity in control mice, but not in MT-null mice. The susceptibility of MT-null mice to acetaminophen hepatotoxicity was not due to the increased acetaminophen bioactivation, as cytochrome P-450 enzymes, and acetaminophen-reactive metabolites in bile and urine were not increased in MT-null mice. Western blots of liver cytosol indicated that acetaminophen covalent binding at 4 h increased with acetaminophen dose, but there was no consistent difference between control and MT-null mice. Acetaminophen injection depleted cellular glutathione similarly in both control and MT-null mice, but produced more lipid peroxidation in MT-null mice, as evidenced by the abundance of thiobarbiturate-reactive substances, and by immunohistochemical localization of 4-hydroxynonenal and malondialdehyde protein adducts. MT-null hepatocytes were more susceptible than control cells to oxidative stress and cytotoxicity produced by N-acetylbenzoquinoneimine, a reactive metabolite of acetaminophen, as determined by oxidation of 2', 7'-dichlorofluorescin diacetate and lactate dehydrogenase leakage. In summary, this study demonstrated that MT deficiency renders animals more vulnerable to acetaminophen-induced hepatotoxicity. The increased sensitivity does not appear to be due to increased acetaminophen activation, glutathione depletion, or covalent binding, but appears to be associated with the antioxidant role of MT.

[In vitro study on the transduction of mutant human dihydrofolate reductase cDNA into human umbilical cord blood CD34+ cells]

OBJECTIVE

To explore whether human umbilical cord blood hematopoietic progenitor cells transduced with mutant dihydrofolate reductase(mDHFR) gene increase resistance to metrotrexate(MTX).

METHODS

Cord blood CD34+ cells were enriched with a high-gradient magnetic cell sorting system(MACS), and then transfected with supernatant of retrovirus containing human mDHFR cDNA. Hematopoietic progenitor clonogenic assay was used to evaluate mDHFR-conferred resistance to MTX.

RESULTS

The purity of cord blood CD34+ cells was approximately 90% and recovery rate was 71.1%. The transduced and mock-transduced CD34+ cells were cultured in mediums containing 20 nmol/L MTX for 14 days. The percentages of progenitor colonies of transduced and mock-transduced CD34+ cells were higher than that of non-transduced (P < 0.01), obviously. The resistance of the former to MTX is nearly twofold of the latter.

CONCLUSION

Transduction of mDHFR gene could confer the resistance of human hematopoietic progenitor cells to MTX toxicity.

A surveillance study on penicillin-resistant streptococcus pneumoniae in China

OBJECTIVES

To find out whether there are also penicillin-resistant streptococcus pneumoniae and the resistant rate in China.

METHODS

A surveillance study which is a part of the international surveillance on pneumococci resistance to penicillin and other antimicrobial agents was conducted in Beijing, China. More than 900 pediatric patients with respiratory tract infections aged from six months to three years selected from two pediatric units were enrolled in the study. Perthroat swabs were immediately streaked onto blood agar plates. Isolates were identified as pneumococci by their typical appearance, gram stain, confirmation tests. Antibiotic susceptibility was assessed by the disk diffusion method and minimal inhibition concentration (MIC) determination according to Protocol and National Committee for Clinical Laboratory Standards (NCCLS).

RESULTS

Of the 51 streptococcus pneumoniae isolates, 5 strains had zones of inhibition indicative of penicillin resistance, of which two had penicillin MICs > or = 0.1 mg/L and were considered to be relatively or fully resistant to penicillin. The MICs of two penicillin resistant strains were 2 mg/L and 4 mg/L. Resistant rates to ceftriaxone and cefotaxime were 0% and 10% respectively. For the other ten antimicrobial agents, the resistant rates were as follows: ampicillin 12%, piperacillin 26%, furbenicillin 14%, cefuroxime 6%, erythromycin 54%, clarithromycin 52%, meleumycin 64%, roxithromycin 52%, chloramphenicol 35%, tetracycline 100%.

CONCLUSIONS

The study suggested that penicillin resistant streptococcus pneumoniae strains existed in China and were also resistant to ampicillin, piperacillin, furbenicillin and cefuroxime. Moreover, the resistant rates of penicillin resistant streptococcus pneumoniae to macrolides and tetracycline were high.

Amplified fragment length polymorphism analysis on D5S436 locus and its application to linkage analysis in gene diagnosis of asthma

OBJECTIVES

To detect the polymorphism of D5S436 locus, and to carry out an amplified fragment length polymorphism (Amp-FLP) genotyping linkage analysis in asthma families.

METHODS

Allele and genotype frequencies of the high polymorphic D5S436 locus were determined in 92 unrelated Chinese individuals by using polymerase chain reaction (PCR). The amplified fragments were separated by denaturing polyacrylamide gel electrophoresis and silver staining techniques.

RESULTS

Eight alleles and 22 genotypes were observed in this population. The heterozygosity was 78.26%. The polymorphism information content (PIC) was 0.76. Amp-FLP genotyping linkage analyses were carried out in four asthma families, demonstrating that the locus was inherited according to Mendel's law and had a clear result.

CONCLUSION

The PIC of D5S436 is high in Chinese individuals, so it could be used as a genetic marker of asthma in Chinese and might be useful in the gene diagnosis of asthma.

All-trans retinoic acid reduces intimal thickening after balloon angioplasty in atherosclerotic rabbits

OBJECTIVE

To investigate the effects of oral administration of all-trans retinoic acid (ATRA) on inhibition of intimal thickening after balloon angioplasty in the rabbit iliac artery atherosclerotic model.

METHODS

Iliac atherosclerosis was induced in 24 rabbits, and balloon angioplasty was performed. At angioplasty, 24 rabbits were randomly divided into four groups (n = 6 per group): Group 1: controls not receiving oral ATRA administration; Group 2: receiving oral ATRA (0.6 mg.kg-1.d-1) administration beginning 1 week prior to angioplasty and continuing for 4 weeks; Group 3: receiving oral ATRA (0.6 mg.kg-1.d-1) administration beginning immediately after angioplasty and continuing for 4 wk; Group 4: receiving oral ATRA (0.6 mg.kg-1.d-1) administration beginning 1 wk after angioplasty and continuing for 4 wk. Values of cross-sectional area, ratio of intimal/medial area and thickness were determined by a computer-based morphometric system, and cell proliferative activity was assessed by 3H-thymidine incorporation.

RESULTS

Both the cross-sectional area and the ratio of intimal/medial area and thickness were significantly reduced by ATRA administration compared with control group (P < 0.01). The inhibitory effect is less potent when ATRA is administered 1 week before angioplasty. The ATRA inhibitory effect when administered 1 week after angioplasty is not different significantly form that when administered immediately after angioplasty. The 3H-thymidine incorporation was also decreased in ATRA-treated rabbits compared with controls (P < 0.01).

CONCLUSIONS

Oral ATRA administration can be effective in inhibiting intimal thickening after balloon angioplasty. It is reasonable that ATRA should be administered immediately after angioplasty.

[Gene diagnosis of factor VIII gene inversion by LD-PCR for 60 patients with severe hemophilia A]

OBJECTIVE

To identify factor VIII(F VIII) gene inversion among 60 patients with severe hemophilia A (HA) in Tianjin region.

METHODS

DNA was extracted from peripheral blood of HA patients; F VIII gene inversion was identified by long distance-polymerase chain reaction(LD-PCR) and 0.6% agarose gel electrophoresis. Those with only 11 kb band were diagnosed as the cases of F VIII gene inversion. Those with only 12 kb band were identified as wild type(non-inversion), and those with both 11 kb and 12 kb bands were recognized as inversion carriers.

RESULTS

There were 21 patients with F VIII gene inversion, accounting for 35% of the 60 patients with severe HA.

CONCLUSION

LD-PCR can be used to detect the F VIII gene inversion directly; it is an effective method for the gene diagnosis of severe hemophilia A.

[Trend of changes in mortality of cardiovascular diseases in some areas of Beijing during 1984 to 1998]

OBJECTIVE

To understand the main causes of deaths affecting population health and the trend of mortality of cardiovascular disease (CVD) in Beijing area during 1984 to 1998.

METHODS

Monitoring data for cardiovascular diseases in some areas of Beijing during 1984 to 1998 were collected from MONICA project and used to analyze the distribution of disease, mortality caused by cardiovascular diseases and its age-adjusted mortality. Yearly average change in cardiovascular disease-specific mortality was calculated with regression analysis.

RESULTS

Cardiovascular disease-specific mortality ranked the first place of the causes of deaths in Beijing population during 1984 to 1998, accounting for 46.0% of the total deaths. Cancer ranked the second, accounting for 26.5% of the total. Overall mortality, cardiovascular-specific mortality and cerebro-specific mortality all lowered significantly during the past 15 years, with yearly average reductions of 2.9%, 2.7% and 3.5%, respectively. Mortality of coronary heart disease significantly rose.

CONCLUSIONS

Cardiovascular disease was the top cause of death in Beijing population during 1984 to 1998. Mortality of coronary heart disease significantly rose in the past 15 years. It is a pressing matter of the moment to prevent cardiovascular diseases in the population.

[Effect of lead exposure in prenatal and postnatal duration on infant growth]

The blood lead (PbB) levels of pregnant women and their babies were followed up since the third month of pregnancy until their babies were 2 years old. The general condition of delivery, family history of the pregnant women, feeding and development of infants were investigated. Prenatal and postnatal PbB levels and their effects on infant growth were analysed. The result showed a significant negative correlation of PbB level of pregnant women near delivery, and in umbilical cord with the growth of infants. Multiple regression analysis showed a negative correlation between PbB level and height, weight of infant at 1 and 2 years old.

Contrast of Highly Dispersed Metal Nanoparticles in High-resolution Secondary Electron and Backscattered Electron Images of Supported Metal Catalysts

Platinum nanoparticles finely dispersed in activated carbon powders have been observed with high contrast in secondary electron (SE) and backscattered electron (BE) images. The factors that contribute to the visibility of small metal particles in high-resolution BE and SE images are discussed. Monte Carlo simulations provided insight into the scattering of electrons by small, heavy-element particles located on, or embedded in, light-element supports. The visibility of Pt nanoparticles in BE images depends on many factors including the size and the location of the Pt particles, the energy of the incident electrons, and the size of the electron probe. The SE signals generated by backscattered electrons may not significantly contribute to the visibility of small Pt particles in high-resolution SE images of carbon supported Pt catalysts. Only those small Pt particles that are located on or very close to the surface of the carbon support can be revealed in high-resolution SE images.

[Intrapulmonary expression of tumor necrosis factor alpha mRNA and its significance in rats with acute pancreatitis]

It is thought that tumor necrosis factor (TNF) plays an important role in pathogenesis of acute lung injury or ARDS. So we want to get insight into the relationship between intrapulmonary expression of TNF-alpha gene and lung injury during acute necrotizing pancreatitis (ANP). In our study, acute edematous pancreatitis (AEP) and ANP were induced in rats by caerulein and sodium taurocholate respectively. After acute pancreatitis was induced, serum TNF-alpha was assessed by ELISA assay while endotoxin was assessed by limulus lysate test. Intrapulmonary expression of TNF-alpha mRNA was detected by semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR) technique. Moreover, content of pulmonary lesion was investigated and graded with microscope. It was found that TNF-alpha concentration in blood elevated markedly after acute pancreatitis was induced, especially in ANP group. Results of RT-PCR revealed that no TNF-alpha mRNA could be detected in lung tissue from those rats undergoing sham-operation, but marked expression appeared 1 hour after AEP or ANP was induced. Upregulation of expression of TNF-alpha gene in the early 3 hours was similar in the two groups with pancreatitis, and since then expression of TNF-alpha mRNA in ANP group was stronger than that in AEP group. Serum endotoxin increased significantly 6 hours after ANP was induced, with a higher level at 12 hour. However, there was no marked change of endotoxin level in AEP group and control group. It is noted that intrapulmonary expression of TNF-alpha gene in ANP group reached its peak as soon as serum endotoxin increased markedly. Lung damage in ANP group was more serious than that in AEP group significantly. Score of lung injury correlated well with TNF-alpha concentration in blood and expression of its gene in lung tissue in either AEP group or ANP group, as well as with serum endotoxin in ANP group. So overwhelm expression of some harmful cytokines like TNF-alpha in lung tissue may be the main cause of lung injury during acute necrotizing pancreatitis, and stimulation of endotoxiemia can at least partly explain the upregulation of expression of TNF-alpha gene.

[Cell cycle analysis and pathological changes of malignant tumors treated with electrochemical therapy]

To investigate the mechanism and to observe the effectiveness of electrochemical therapy(ECT), 33 patients of late stage cancers which treated by ECT were included in this study. Flow cytometry (FCM) and pathology were used to observe the changes of tumor cells before and after ECT. Tumor cells of G1, G2/M, S phases and aneuploid cells were found to be killed almostly and the ratio of apoptosis was elevated greatly after ECT. Also, pathological evidence proved the death of tumor cells and some characters of apoptosis. So, ECT can non-selectively kill tumor cells and induce the apoptosis of them, and FCM was a way to evaluate the effectiveness of ECT.

[Determination of decomposition products of di-t-butyl peroxide by gas chromatography]

In this work we found that there were five decomposition products of di-t-butyl peroxide at 320 degrees C by GC-MS. The peak area of acetone as a chief product in the thermal decomposition was related to di-t-butyl peroxide concentration in a linear manner. The range was from 22.91 to 114.93 microg (r=0.9997, n=4). By use of the calibration, we can possibly determine the content of the peroxide rapidly. The present method is more suitable for the determination of peroxide that is liable to decompose and difficult to be vaporized.

[Effects of high dose of dynorphin on NMDA receptor and NOS activities in spinal cord of rats]

OBJECTIVE

To elucidate the effects of N-methyl-D-aspartate(NMDA) receptor and nitric oxide synthase (NOS) activity in dynorphin (Dyn)-induced spinal cord injury.

METHODS

The NMDA receptor activity was measured by radio-ligand of 3H-MK801. The constitutive and inducible NOS (cNOS and iNOS) activities were assayed by 3H-arginine conversion.

RESULTS

In ventral samples, both 3H-MK801 binding and cNOS activity increased at 0.5 h and persisted for 48 h while iNOS activity enhanced at 4 h after intratheacal injection (i.t.) Dyn A(1-17) at dose of 20 nmol/L. However, the 3H-MK801 binding activity reduced significantly from 4 h to 24 h and cNOS activity did not change at the same time in dorsal samples. 7-nitroindozol (7-NI) and aminoguanidine (AG) inhibited the effects of Dyn A(1-17) (20 nmol/L) on 3H-MK801 binding and NOS activities in ventral samples. N-nitro-L-arginine methyl ester (L-NAME) did not affect the elevation of Dyn A(1-17) on NOS activities but caused 3H-MK801 binding activity reduction in ventral samples.

CONCLUSIONS

NMDA-NOS pathway might play important role in Dyn spinal neurotoxicity. NOS inhibitors and Dyn might produce cooperative down-regulation on the function of NMDA-NOS pathway in dorsal cord.

Effects of XW630 on bone formation in ovariectomized rats and in human osteoblast-like cells

OBJECTIVE

To study the effects of XW630 on bone formation in overiectomized (OVX) rats and in human osteoblast-like cell line TE85.

METHOD

Bone histomorphometric analysis was performed with undecalcified bone sections and tetracycline intraperitoneally labeling.

RESULTS

Compared with that of OVX rats, the static data of trabecular bone volume (TBV)/total tissue volume (TTV), TBV/sponge bone volume (SBV) and mean trabecular plate density (MTPD) were enhanced while mean trabecular plate spacing (MTPS) decreased after treated with XW630 for 13w. The dynamic data of single-labeled surface [Sfract(s)], double-labeled surface [Sfract(d)], Sfract(d+1/2s), trabecular osteoid surface (TOS) and bone formation rate in tissue level (Svf) were increased and osteoid maturation period (OMP) shortened in XW630 group. In osteoblast-like cells, both 3H-thymidine incorporation and cell count increased after treated with XW630 for 48. Treated with XW630 for 12 approximately 18h, inducible nitric oxide synthase (iNOS) activity and cGMP content increased in time-dependent manners.

CONCLUSIONS

XW630 enhanced bone activation frequency and increased trabecular connectivity, stability, and strength. The cellular mechanism related to effects of XW630 on bone formation in ovariectomized rats.

[Studies on tissue culture of Dendrobium chrysotoxum Lindl in vitro]

OBJECTIVE

To set up a system for the culture of Dendrobium chrysotoxum in vitro.

METHOD

Tissue culture, fire fly luminescence and phenol-H2SO4 method.

RESULT

The embryo could germinate with or without light, the MS, 1/2MS, B5, N6 mediums are suitable to the growth and the differentiation of sprout with light, 0.5 mg.L-1 NAA and 1 mg.L-1 6-BA, and ATP have regular changes, the content of polysaccharide was 2.833% in plant and 7.254% in sprout.

CONCLUSION

The light has no effects on the embryo germination, but the phytohormone, nitrogen source and organized elements are important to the growth and differentiation of the sprout which should be transferred to the MS, 1/2MS, B5, N6 mediums in time supplemented with NAA [symbol: see text] 6-BA, ATP may be served as the dynamic indication of nourishment demand in the plant. The content of polysaccharide in the sprout is higher and can be utilized.

[An experimental study on bone marrow purging in vitro for patients with chronic myelogenous leukemia]

OBJECTIVE

To investigate the effect of IL-2, IFN and bcr-abl AS-ODN on bone marrow purging in vitro for patients with chronic myelogenous leukemia (CML).

METHODS

By amplifying in vitro clone forming culture, and purging the bone marrow of 5 CML patients through different combined use of IL-2, IFN and bcr-abl AS-ODN, we compared the effects of 4 combined regimens.

RESULTS

It was found that the suppressive effects of the 4th regimen combining IL-2 (800 U/ml), IFN (800 u/ml) and bcr-abl AS-ODN (30 micrograms/ml) on leukemia cell clone forming unit (CFU) were significantly different from the suppressive effects of the other 3 regimens (P < 0.01). With the use of the 4th regimen, the GM-CFU and L-CFU survival rates were 26.91% and 3.49% respectively (P < 0.01).

CONCLUSION

The combined regimen of IL-2 (800 U/ml), IFN (800 u/ml) and bcr-abl AS-ODN (30 micrograms/ml) has good effect on selective CML bone marrow purging in vitro and can be used in clinical purging of CML bone marrow.

[Effect of estrogen on the expression of c-myc protein of bone in mice]

In order to study the mechanism by which estrogen effects on bone, the effect of estrone on expression of c-myc protein in the epiphyseal plate of fetal mouse long bone was detected by immunohistochemistry procedure in vitro. The result showed that the concentrations of estrone areas of positively staining cells increased significantly in proliferative zone at 10(-9) mol/L, in proliferative zone and resting zone at 10(-8) mol/L, and in resting zone, proliferative zone and hypertrophic zone at 10(-7) mol/L respectively. It was considered that estrogen might enforce endochondral bone formation by enhancing expression of c-myc in long bone.

Inheritance of plant regeneration from maize (Zea mays L.) shoot meristem cultures derived from germinated seeds and the identification of associated RAPD and SSR markers

The inheritance of shoot regeneration through shoot-tip meristem culture derived from maize seedling was evaluated, and the markers (RAPD and SSR) associated with this regeneration character were identified both in a group of North American maize inbreds and a crossing population. A discrete distribution of percent regeneration and no. of shoots per explant was observed in the inbred group and the F(2) population. The results suggested that this regenerable trait was controlled by several major genes. Five RAPD markers were identified to be relevant to percent regeneration in maize shoot-tip culture system. One RAPD marker and three SSR markers were associated with no. of shoot per explant and its relevant traits. Of them marker BC603-1600 explained 18% of the variation for no. of shoot per explant and 16% of the variation for callus size. The BC603-1600 was sequenced and assigned in linkage group 7 based on a NCBI blast search. The information provided here should benefit to determine the genetic mechanisms involved in the maize regeneration response related to shoot meristem culture pathway and benefit to select high regenerable germplasm by using marker assisted selection.

Performance analysis on hybrid ventilation system for residential buildings using a test house

Hybrid ventilation system is a two-mode system that can automatically switch between passive and mechanical modes at different times of the day or season of the year. In this study various ventilation systems, including hybrid system, are used for the investigation. These systems are set up in a full-scale test house constructed in the Tohoku University, Japan. Case studies for evaluating the performance of these systems, by field studies and numerical simulations, are described. The results obtained from this study show that, the hybrid system can supplement the under-ventilation even under a milder weather condition and the airflow rate can be fixed at a certain high level, in comparison with passive system.