Bilateral repetitive transcranial magnetic stimulation for treatment-resistant depression: a systematic review and meta-analysis of randomized controlled trials

There has been concern regarding the use of controversial paradigms for repetitive transcranial magnetic stimulation (rTMS) to manage treatment-resistant depression (TRD). This meta-analysis assessed the efficacy of bilateral rTMS compared with unilateral and sham rTMS in patients with TRD. PubMed, Embase, CENTRAL, PsycINFO, Web of Science, EAGLE and NTIS databases were searched to identify relevant studies, and randomized controlled trials (RCTs) on bilateral rTMS for TRD patients were included. The response was defined as the primary outcome, and remission was the secondary outcome. Ten RCTs that included 634 patients met the eligibility criteria. The risk ratio (RRs) of both the primary and secondary outcomes of bilateral rTMS showed non-significant increases compared to unilateral rTMS (RR=1.01, P=0.93; odds ratio [OR]=0.77, P=0.22). Notably, the RR of the primary bilateral rTMS outcome was significantly increased compared to that for sham rTMS (RR=3.43, P=0.0004). The results of our analysis demonstrated that bilateral rTMS was significantly more effective than sham rTMS but not unilateral rTMS in patients with TRD. Thus, bilateral rTMS may not be a useful paradigm for patients with TRD.

Advanced oxidation protein products as a biomarker of cutaneous lupus erythematosus complicated by nephritis: a case-control study

Oxidative stress is involved in the pathogenesis of lupus nephritis (LN). The current study investigated the significance of advanced oxidation protein products (AOPPs) as a biomarker of LN in patients with cutaneous lupus erythematosus. Ninety-two patients who initially presented with systemic lupus erythematosus were divided into the LN- and LN+ groups. Serum AOPP levels were determined, and the association between AOPP levels and LN was investigated in a case-control study. In the LN+ group, patients with higher AOPP levels exhibited higher levels of dsDNA and proteinuria but lower levels of eGFR and complement C3 compared to those in patients with lower AOPP levels. A multivariable logistic regression model showed that the AOPP level was an independent risk factor for LN. The risk of nephritis specifically increased 24% for each 10 μM increase in AOPP (95% confidence interval, 1.166-1.915, P = 0.030). In contrast, neither elevated dsDNA level nor decreased complement C3 level was an independent risk factor for LN. Higher serum AOPP levels were associated with an increased risk of LN. Therefore, future studies are warranted to determine the potential clinical value of this novel biomarker.

Meta-analysis on the efficacy and tolerability of the augmentation of antidepressants with atypical antipsychotics in patients with major depressive disorder

We assessed the efficacy and tolerability of the augmentation of antidepressants (ATDs) with atypical antipsychotics (AAPs) to treat patients with major depressive disorder. A retrograde study to identify relevant patient data included databases of PubMed, EMBASE, Cochrane Central Register of Controlled Trials, and Database of Abstracts of Reviews of Effects. Data from 17 trials, involving 3807 participants, were identified. The remission rate (RR) and overall response rate (ORR) of adjunctive treatment with AAPs were significantly higher than placebo treatment: RR=1.90 (95%CI=1.61-2.23, z=7.74, P<0.00001) and ORR=1.68 (95%CI=1.45-1.94, z=7.07, P<0.00001). We found that the short-term (4 weeks) treatment [ORR=1.70 (95%CI=0.98-2.95, Z=1.89, P=0.06)] was significantly different from the long-term (6-12 weeks) treatment [ORR=1.68 (95%CI=1.45-1.94, z=7.07, P<0.00001)]. No significant difference in ORR was observed between groups with or without sedative drugs. The discontinuation rate due to adverse effects was higher for adjunctive treatment with AAPs: ORR=3.32 (95%CI=2.35-4.70, z=6.78, P<0.00001). These results demonstrate that the augmentation of ATDs with AAPs (olanzapine, quetiapine, aripiprazole, and risperidone) was more effective than a placebo in improving response and remission rates, although associated with a higher discontinuation rate due to adverse effects.

Effect of CDH1 gene methylation on transforming growth factor (TGF-β)-induced epithelial-mesenchymal transition in alveolar epithelial cell line A549

The aim of this study was to investigate the specific molecular mechanism of the transforming growth factor β (TGF-β)-induced epithelial-mesenchymal transition in a lung cancer cell line, and to provide new ideas for targeting therapy of lung cancer. A549 cells were treated with different concentrations of TGF-β and 5-aza-deoxycytidine (5-aza-dC). The morphological changes after the intervention were observed. The change in the expression of the epithelial marker E-cadherin (E-cad) was detected by Western blot. The proliferation of A549 cells was measured using the MTT assay. Cell movement and invasion capacity was evaluated with the cell scratch test and invasion test. TGF-β induced A549 cells to transform to a mesenchymal cell morphology and downregulated the expression of E-cad, and 5-aza-dC inhibited this phenomenon. Compared with the control group, the number of transmembrane cells was higher and cell migration was markedly increased in the experimental group with continued culture in the presence of 10 ng/mL TGF-β, showing significant differences (P < 0.05). CDH1 gene methylation is involved in TGF-β-induced epithelial-mesenchymal transition in the alveolar epithelial cell line A549.

Enhanced tumor accumulation and cellular uptake of liposomes modified with ether-bond linked cholesterol derivatives

Novel liposomal formulations based on cholesterol modification had been designed previously by our lab, but we found them with a poor stability and short half-life, especially in blood circulation. The results might be attributed to the hydrolysis of ester linked cholesterol derivatives by esterase in plasma. Thus, in this study, we newly synthesized ether-linked cholesterol derivatives and compared them to other preparations. A comparison with the substrate cholesterol-PEG2000-maleimide showed that ether-linked cholesterol-PEG2000-maleimide could relatively maintain integrity in serum, with only a small mottle emerging on TLC (thin-layer chromatography) plates through the experiment. Then a cell-penetrating peptide TAT was attached to the distal end of CHO-PEG2000 to prepare liposomes and to further evaluate the two cholesterol derivatives. Optimized liposomes (65:35, lipid/cholesterol, molar ratio) composed of 3% CHO-PEG2000 and 3% CHO-PEG2000-TAT showed good stability in 50%FBS (fetal bovine serum). In vitro experiments showed that as incubation time prolonged, ether-linked-TAT LIP showed a 3.67-fold higher uptake amount than ester-linked-TAT LIP. In vivo, ether-linked-TAT LIP accumulated better in tumors and had a 40% higher cellular uptake amount. Altogether, we could conclude that our newly ether-linked cholesterol derivatives possessed better stability especially in blood circulation which led to increased tumor cellular uptake in vitro and in vivo. Our study may offer a better way in cholesterol modification to prepare functionalized liposomes.

Glucose regulates secretion of exogenously expressed insulin from HepG2 cells in vitro and in a mouse model of diabetes mellitus in vivo

Glucose-controlled insulin secretion is a key component of its regulation. Here, we examined whether liver cell secretion of insulin derived from an engineered construct can be regulated by glucose. Adenovirus constructs were designed to express proinsulin or mature insulin containing the conditional binding domain (CBD). This motif binds GRP78 (HSPA5), an endoplasmic reticulum (ER) protein that enables the chimeric hormone to enter into and stay within the ER until glucose regulates its release from the organelle. Infected HepG2 cells expressed proinsulin mRNA and the protein containing the CBD. Immunocytochemistry studies suggested that GRP78 and proinsulin appeared together in the ER of the cell. The amount of hormone released from infected cells varied directly with the ambient concentration of glucose in the media. Glucose-regulated release of the hormone from infected cells was rapid and sustained. Removal of glucose from the cells decreased release of the hormone. In streptozotocin-induced diabetic mice, when infected with adenovirus expressing mature insulin, glucose levels declined. Our data show that glucose regulates release of exogenously expressed insulin from the ER of liver cells. This approach may be useful in devising new ways to treat diabetes mellitus.

Cellular stress response in Eca-109 cells inhibits apoptosis during early exposure to isorhamnetin

The flavonol aglycone isorhamnetin shows anti-proliferative activity in a variety of cancer cells. Previous work, from our laboratory showed that isorhamnetin inhibits the proliferation of human esophageal squamous carcinoma Eca-109 cells in vitro, but only after 72 h of exposure. This led us to propose that isorhamnetin exposure induces a cellular stress response that inhibits the antiproliferative and apoptotic effects of the compound during early exposure. To test this hypothesis, the present study examined the effects of isorhamnetin on Eca-109 cells during the first 72 h of exposure. Cell growth was assessed using the trypan blue exclusion assay, and expression of IκBα, NF-κB/p65, NF-κB/p50, phospho-Akt, Bcl-2, COX-2, Mcl-1, Bax, p53 and Id-1 were analyzed by Western blot. During the first 72 h of exposure, NF-κB/p65 and NF-κB/p50 accumulated in nuclei and expression of COX-2, Bcl-2 and Mcl-1 increased. In contrast, expression of IκBα and Bax fell initially but later increased. Expression of phospho-Akt and p53 showed no detectable change during the first 48 h. Pretreatment with the NF-κB inhibitor MG132 before exposure to isorhamnetin blocked the nuclear accumulation of p50 and p65, thereby inhibiting cell proliferation. These results show that during early exposure of Eca-109 cells to isorhamnetin, the NF-κB signaling pathway is activated and COX-2 expression increases, and this increase in expression partially inhibits isorhamnetin-induced apoptosis. Beyond 72 h of exposure, however, the apoptotic effect of isorhamnetin dominates, leading to inhibition of the NF-κB pathway and of cellular proliferation. These results will need to be taken into account when exploring the use of isorhamnetin against cancer in vivo.

Controlling magnetoelectric coupling by nanoscale phase transformation in strain engineered bismuth ferrite

The magnetoelectric coupling in multiferroic materials is promising for a wide range of applications, yet manipulating magnetic ordering by electric field proves elusive to obtain and difficult to control. In this paper, we explore the prospect of controlling magnetic ordering in misfit strained bismuth ferrite (BiFeO(3), BFO) films, combining theoretical analysis, numerical simulations, and experimental characterizations. Electric field induced transformation from a tetragonal phase to a distorted rhombohedral one in strain engineered BFO films has been identified by thermodynamic analysis, and realized by scanning probe microscopy (SPM) experiment. By breaking the rotational symmetry of a tip-induced electric field as suggested by phase field simulation, the morphology of distorted rhombohedral variants has been delicately controlled and regulated. Such capabilities enable nanoscale control of magnetoelectric coupling in strain engineered BFO films that is difficult to achieve otherwise, as demonstrated by phase field simulations.

Effects of preventive acupuncture on streptozotocin-induced hyperglycemia in rats

BACKGROUND

Diabetes prevention has received increasing attention recently. Clinical and experimental studies showed that acupuncture could produce hypoglycemic effect. However, little is known about the effectiveness of acupuncture in diabetes prevention.

AIM

To investigate the preventive effects of acupuncture on streptozotocin (STZ)-induced hyperglycemia in rats.

METHODS

Hyperglycemia was induced by a single intraperitoneal injection of STZ (60 mg/kg). Rats were randomly divided into six groups (no.=8 each group): control, diabetes, preventive acupuncture plus STZ injection, STZ injection plus therapeutic acupuncture, STZ injection plus preventive and therapeutic acupuncture, and preventive and therapeutic acupuncture control. Body weight, blood glucose, serum insulin, lipid peroxidation, and antioxidant enzymes were measured by routine standard methods. Histological analysis of pancreatic islets was conducted.

RESULTS

Preventive acupuncture significantly relieved hyperglycemia, insulin deficiency, weight loss, and pancreatic islet damage in rats with STZ injection; it also significantly reduced serum lipid peroxidation and enhanced superoxide dismutase in the serum and the pancreas without significantly affecting serum glutathione peroxidase and catalase. Therapeutic acupuncture exhibited a hypoglycemic effect in the late stage, but did not significantly improve other parameters.

CONCLUSIONS

These results indicate that preventive acupuncture is beneficial to the control of STZ-induced hyperglycemia in rats.

Molecular analysis of the coat protein gene of peanut stripe virus from China

Peanut stripe virus (PStV) is one of the most common viruses infecting peanut that causes great economic losses every year. The 3ʹ-terminal 1082 bp of 74 PStV isolates collected from 12 districts of Shandong province, China were sequenced. Their coat protein (CP) genes were 864 bp in length and shared identities of 98.0%~100% and 98.3% ~100% at nt and aa levels. The identities between the CP genes of these isolates and other 36 isolates from the GenBank were 93.5%~100% and 92.0%~100% at nt and aa levels, respectively. PStV isolates can be clustered into two phylogenetic groups. The isolates from United States, mainland China, and Indonesia formed group I and those from Viet Nam, Thailand, and Taiwan formed group II. The PStV isolates in group I can be further classified to two subgroups. The gene flow of PStV populations within a country was frequent, but that between countries was infrequent.

Pharmacokinetics, tissue distribution and excretion study of dl-praeruptorin A of Peucedanum praeruptorum in rats by liquid chromatography tandem mass spectrometry

dl-Praeruptorin A (Pd-Ia), isolated from Chinese traditional herbal medicine Peucedanum praeruptorum Dunn, has been proved to be a novel Ca²+-influx blocker and K+-channel opener, and displayed bright prospects in prevention and therapy of cardiac diseases. The aim of this study was to investigate the pharmacokinetics, tissue distribution and excretion of Pd-Ia in rats following a single intravenous (i.v.) administration. The levels of Pd-Ia in plasma, tissues, bile, urine and feces were measured by a rapid and sensitive liquid chromatography-tandem mass spectrometry (LC-MS/MS) method. The results showed that Pd-Ia was rapidly distributed and then eliminated from rat plasma and manifested linear dynamics in dose range of 5-20 mg/kg. The mean elimination half-life (t(½) of Pd-Ia for 5, 10 and 20 mg/kg dose were 57.46, 60.87 and 59.01 min, respectively. The major distribution tissues of Pd-Ia in rats were spleen, heart and lung, and low polarity enabled Pd-Ia to cross the blood-brain barrier. There was no long-term accumulation of Pd-Ia in rat tissues. Total recoveries of Pd-Ia within 24 h were low (0.097% in bile, 0.120% in urine and 0.009% in feces), which might be resulted from liver first pass effect.

Genetic diversity of Potato virus Y infecting tobacco crops in China

Genetic variability of Potato virus Y (PVY) isolates infecting potato has been characterized but little is known about genetic diversity of PVY isolates infecting tobacco crops. In this study, PVY isolates were collected from major tobacco-growing areas in China and single-lesion isolates were produced by serial inoculation on Chenopodium amaranticolor. Most isolates (88%) caused systemic veinal necrosis symptoms in tobacco. Of these, 16 isolates contained a PVY(O)-like coat protein (CP) and PVY(N)-like helper component proteinase (HC-pro) and, in this respect, were similar to the PVY(N-Wi), PVY(N:O), and PVY-HN2 isolates characterized from potato in Europe, the United States, and China, respectively; two isolates contained a PVY(O)-like HC-pro and a PVY(N)-like CP; another two isolates had recombination junctions in the CP-encoding region. Both the HC-pro and CP of PVY were under negative selection as a whole; however, seven amino acids in HC-pro and six amino acids in CP were under positive selection. Selection pressures differed between the subpopulations of PVY distinguished by phylogenetic analysis of HC-pro and CP sequences. When PVY isolates from potato were included, no host-specific clustering of the PVY isolates was observed in phylogenetic and nucleotide diversity analyses, suggesting frequent spread of PVY isolates between potato and tobacco crops in the field.

+Antisense oligonucleotide targeting survivin inhibits growth by inducing apoptosis in human osteosarcoma cells MG-63

Survivin may play an important role in the development of osteosarcoma. In this study, we chose osteosarcoma cell line MG-63, which highly expressed survivin, to observe the effects of antisense oligonucleotide targeting survivin on the apoptosis induction and proliferation inhibition. It was shown in our results that the apoptosis rate and the proliferation inhibition rate increased significantly in survivin-positive cells MG-63 by using MTT and flow cytometry methods. We found that the growth inhibition rate and apoptosis rate were changed in a dose-dependent way. When the concentration of antisurvivin oligonucleotide was 600 nM, the effects reached the peak. RT-PCR and western-blot methods were used to detect the mRNA and protein expression of survivin in MG-63. We observed that the mRNA and protein expression of survivin reduced after transfected with antisurvivin oligonucleotides at the concentration of 200 nM, 400 nM and 600 nM. At the same time, we found that the mRNA and protein expression of Fas were up-regulated with the concentration of antisurvivin oligonucleotides from 200 nM to 600 nM. It was negative associated with the expression change of survivin. These data suggested that survivin should play an important role in the development of osteosarcoma and the survivin blockaded by using antisurvivin oligonucleotide could inhibit the proliferation and induce apoptosis of osteosarcoma by decreasing the expression of survivin and activate the Fas-mediated apoptosis. Down-regulation of survivin by antisense oligonucleotide might be an effective strategy to the treatment of osteosarcoma and might improve the therapeutic effect.

KEYWORDS

osteosarcoma, Survivin, apoptosis, Fas.

Identification of differentially expressed genes at two key endosperm development stages using two maize inbreds with large and small grain and integration with detected QTL for grain weight

Maize endosperm accounts for more than 80% of the grain weight. Cell division and grain filling are the two key stages for endosperm development. Previous studies showed that gene expression during differential stages in endosperm development is greatly different. However, information on systematic identification and characterization of the differentially expressed genes between the two stages are limited. In this study, suppression subtractive hybridization (SSH) was used to generate four subtracted cDNA libraries for the two stages using two maize inbreds with large and small grain. Totally, 4,784 differentially expressed sequence tags (ESTs) were sequenced and 902 were non-redundant, which consisted of 344 unique ESTs. Among them 192 had high sequence similarity to the GenBank entries and represent diverse of functional categories, such as metabolism, cell growth/division, transcription, signal transduction, protein destination/storage, protein synthesis and others. The expression patterns of 75.7% SSH-derived cDNAs were confirmed by reverse Northern blot and semi-quantitative reverse transcription polymerase chain reaction, and exhibited the similar results (75.0%). Genes differentially expressed between two key stages for the two inbreds were involved in diverse physiological process pathway, which might be responsible for the formation of grain weight. 43.8% (70 of the 160 unique ESTs) of the identified ESTs were assigned to 39 chromosome bins distributed over all ten maize chromosomes. Eleven ESTs were found to co-localize with previous detected QTLs for grain weight, which might be considered as the candidate genes of grain weight for further study.

RACK1, a potential target to decrease morphine reward in mice

Morphine reexposure induces the decrease of receptor for activated C-kinase 1 protein (RACK1) levels in frontal cortex, and the increase of p-ERK (extracellular signal-regulated kinase) levels in mouse frontal cortex, striatum, hippocampus and nucleus accumbens (NAcc). Moreover, RACK1 is associated with the core kinases of the ERK pathway, Raf, MEK, and ERK. The purpose of this study is to investigate the effect of overexpression of RACK1 on the conditioned place preference (CPP) and the level of p-ERK in morphine reexposure mice. Mice were subcutaneously injected with morphine on the 2nd, 4th, 6th, and the 8th day, saline was delivered the next day. After mice showed place preference, RACK1 was administered by intraventricular injection 20 minutes after injection of morphine on the 11th, 13th, 15th, and 17th day. CPP was measured on the 18th day. It was found that morphine reexposured mice showed a decreased RACK1 level in the frontal cortex, striatum and an increased RACK1 level in hippocampus and NAcc, but this effect was reversed after administration of RACK1. In this study we demonstrated that RACK1 decreased p-ERK and erased CPP during reexposure of morphine and there was no an effect in reexposure saline mice. It strongly suggests that RACK1 may play a crucial role in morphine reexposured mice and the RACK1 has the potential to be a remedy to the morphine reward.

Comparison of three diagnosis criteria for metabolic syndrome in Mongolian people of agricultural and pastoral regions

OBJECTIVE

To compare application of the metabolic syndrome (MetS) 3 definitions, proposed by International Diabetes Federation (IDF) in 2005, Adult Treatment Panel III (ATPIII) in 2005 and Chinese Diabetes Society (CDS) in 2004, in Mongolian people of agricultural and pastoral areas in Inner Mongolia, China.

METHODS

A cross-sectional survey was conducted in Chaoluto and Guribanhua township of Tongliao City of Inner Mongolia, between June 2003 and August 2004. A total of 2536 Mongolian people aged 20 yr and older completed all the surveys and examinations. Anthropometry, blood pressure, and fasting biochemistry were measured according to standard methods.

RESULTS

The age-standardized prevalence of MetS using the IDF, ATPIII, and CDS definitions was 17.1% (men 11.4%, women 21.6%), 22.9% (men 19.6%, women 25.8%) and 8.1% (men 7.6%, women 8.6%), respectively. The agreement of IDF and ATPIII, IDF and CDS, ATPIII and CDS were 93.5%, 85.0%, and 81.6%, and Kappa values were 0.822, 0.434, and 0.419, respectively. Among the subjects who had 3 or more MetS components, 100% were screened by ATPIII criteria, 76.1% by IDF criteria (men 57.3%, women 85.7%), and 33.5% by CDS criteria (men 7.6%, women 8.6%) respectively.

CONCLUSIONS

This investigation in Mongolian people showed very high agreement between IDF and ATPIII definitions, and moderate agreement between CDS and 2 other criteria. The cut points of waist circumference for males in IDF and ATPIII seemed high, and whether CDS definition should lower the fasting plasma glucose value from 6.1 to 5.6 mmol/l needs examination through further prospective studies in the Chinese population.

Anti-tumour effects of exosomes in combination with cyclophosphamide and polyinosinic-polycytidylic acid

We examined the anti-tumour activity of exosomes derived from dendritic cells (DCs) in combination with cyclophosphamide (CTX) and polyinosinic-polycytidylic acid sodium salt (poly I:C). DCs were pulsed with L1210 lymphocytic leukaemia cell antigen and lipopolysaccharide. The exosomes that the DCs secreted were purified. In vitro, the anti-tumour activity of exosomes was assessed by measuring their ability to induce spleen cell proliferation and the extent to which they induced spleen cells to kill L1210 cells. Poly I:C was able to induce DC maturation. DC-derived exosomes stimulated spleen cell proliferation and enhanced the cytotoxic effects of spleen cells in vitro. DC-derived exosomes, in combination with CTX and poly I:C, suppressed L1210 tumour growth in vivo and gave the greatest prolongation of survival time in tumour-bearing DBA2 mice. These findings suggest that this combination of a tumour vaccine, a conventional anti-cancer agent and a promoter of DC maturation might be a useful anti-cancer therapy.

Molecular variability of five Cucumber mosaic virus isolates from China

Cucumber mosaic virus (CMV) isolates are currently divided into two main groups, I and II according to their genomic sequences. The group I is further divided into two subgroups IA and IB. We performed a phylogenetic analysis of the genome regions containing 1a, 2a, 2b, coat protein (CP), and movement protein (MP) genes of 5 CMV isolates from China and other 28 CMV isolates available in the GenBank. The results indicated that CMV isolates could be genetically divided into three groups I, II, and III according to the genes encoding MP, CP, 1a, and 2a proteins and to the 2 groups according to the gene 2b. Group I could be further divided into two subgroups (IA and IB) according to the genes encoding CP, MP, 2a, and 2b proteins and to the three subgroups (IA, IB, and IC) according to the gene encoding 1a protein. Four of 5 examined Chinese CMV isolates belonged to the subgroup IB, while the remaining isolate was a natural inter-subgroup reassortant. We found that the 2b gene of CMV was under positive selection, while the other genes were under negative selection. No evidence of the selection associated with a host adaptation or geographic distribution was found.

Urinary metabolites and health effects in workers exposed chronically to chloronitrobenzene

For workers exposed to 4-chloronitrobenzene (4CNB), the major metabolites were determined. Urine were analysed before and after acid hydrolysis to qualify the free and conjugated metabolites of 4CNB. Three conjugated metabolites were identified in exposed workers: the mercapturic acid N-acetyl-S-(4-nitrophenyl)-L-cysteine (NANPC) was the only metabolite detected in non-hydrolysed urine, and accounted for approximately 51% of the total metabolites detected. The two remaining metabolites 4-chloroaniline (4CA) and 2-chloro-5-nitrophenol (CNP) were identified as cleavage products in hydrolysed urine, and accounted for approximately 18 and 30% of the total metabolites detected, respectively. No metabolites were found in factory controls within the limits of quantitation (LOQ) of the assay. There is a moderate correlation between NANPC and both 4CA and CNP. The correlation between 4CA and CNP is minor. The correlation between the total metabolites and both 4CA and CNP are good. The best correlation was found between the total metabolites and NANPC. There is a moderate inverse correlation between age and the creatinine levels. The raw metabolite levels CNP and NANPC decrease with age. The urine metabolites increase and correlate significantly with the creatinine levels. 4CA, NANPC and the total metabolite levels correlate with the haemoglobin adduct levels. NANPC is the most appropriate biomarker in the urine for a recent absorbed dose of 4CNB, since NANPC reflects the levels of 4CA and CNP and is the most prevalent metabolite detected in all the exposed workers.

Comparison of biomarkers in workers exposed to 2,4,6-trinitrotoluene

2,4,6-Trinitrotoluene (TNT) is an important occupational and environmental pollutant. In TNT-exposed humans, notable toxic manifestations have included aplastic anaemia, toxic hepatitis, cataracts, hepatomegaly, and liver cancer. Therefore, methods were developed to biomonitor workers exposed to TNT. The workers were employed in a typical ammunition factory in China. The external dose (air levels and skin exposure), the internal dose (urinary metabolites), the biologically effective dose (haemoglobin adducts, urinary mutagenicity), biological effects (chromosomal aberrations and health effects), and individual susceptibility (genotypes of xenobiotic-metabolizing enzymes) were determined. Haemoglobin-adducts of TNT, 4-amino-2,6-dinitrotoluene (4ADNT) and 2-amino-4,6-dinitrotoluene (2ADNT), and the urinary metabolites of TNT, 4ADNT and 2ADNT, were found in all workers and in some controls. The levels of the haemoglobin-adducts or the urinary metabolites correlated weakly with the skin or air levels of TNT. The urinary mutagenicity determined in a subset of workers correlated strongly with the levels of 4ADNT and 2ADNT in urine. The haemoglobin-adducts correlated moderately with the urinary metabolites and with the urinary mutagenicity. The genotypes of glutathione S-transferases (GSTM1, GSTT1, GSTP1) and N-acetyltransferases (NAT1, NAT2) were determined. In general, the genotypes did not significantly influence the haemoglobin-adduct levels and the urine metabolite levels. However, TNT-exposed workers who carried the NAT1 rapid acetylator genotype showed an increase in urinary mutagenicity and chromosomal aberrations as compared with slow acetylators. The haemoglobin adduct 4ADNT was significantly associated with a risk of hepatomegaly, splenomegaly and cataract; urine metabolites and genotypes were not associated with health effects. These results indicate that a set of well-selected biomarkers may be more informative regarding exposure and effect than routinely performed chemical measurements of pollutants in the air or on the skin.

Urinary metabolites of workers exposed to nitrotoluenes

Nitrotoluenes are important intermediates in the chemical industry. 2,6-Dinitrotoluene (26DNT), 2,4-dinitrotoluene (24DNT) and 2-nitrotoluene (2NT) are carcinogenic in animals and possibly carcinogenic in humans. Thus, it is important to develop methods to biomonitor workers exposed to such chemicals. The authors have monitored the air and urine metabolite levels for a group of workers in China exposed to 24DNT, 26DNT, 2NT and 4-nitrotoluene (4NT). The metabolites 2,4-dinitrobenzylalcohol (24DNBAlc), 2-amino-4-nitrobenzoic acid (2A4NBA), 4-amino-2-nitrobenzoic acid (4A2NBA) and 2,4-dinitrobenzoic acid (24DNBA) resulting from exposure to 24DNT were found in 89, 88, 91 and 78% of the exposed workers, respectively. The metabolites 2,6-dinitrobenzylalcohol (26DNBAlc) and 2,6-dinitrobenzoic acid resulting from 26DNT exposure were found in 99 and 86% of the exposed workers, respectively. Quantitatively, 2A4NBA, 4A2NBA and 26DNBAlc were the major metabolites. The nitrobenzoic acids were the major metabolites resulting from exposure to 2NT and 4NT and were present in 96 and 73% of the exposed workers, respectively. Air concentrations of DNT and 2NT did not correlate with the levels of metabolites in the urine. In conclusion, the dinitrobenzyl alcohols and aminonitrobenzoic acids determined in the urine provided a good marker for recently absorbed dose and were intrinsically related to the bioactivation and detoxification pathways of DNT. Air measurements were not a good measure to predict internal exposure.

Effect of fermented soybean meal on intestinal morphology and digestive enzyme activities in weaned piglets

The objective of the current experiment was to investigate the effect of Bacillus subtilis fermented soybean meal (FSBM) on intestinal morphology and digestive enzyme activities in piglets. Sixty crossbred (Duroc x Landrance x Yorkshire) piglets at an average weight of 8.62 kg were randomly allotted to two treatments and fed diets containing soybean meal (SBM) and FSBM, respectively. At the end of the experimental period, six piglets of each treatment were slaughtered humanly to collect the contents and tissue samples at three different locations in small intestine. Light microscopy and scanning electron indicated that piglets fed FSBM had a higher (P<0.05) villus height at three different locations of small intestine and had la ower (P<0.05) crypt depth in the duodenum compared to piglets fed SBM. The results showed that activities of total protease and trypsin at the duodenum and jejunum of piglets fed with FSBM increased (P<0.05) compared with the control. The trypsin activity in the pancreas of piglets decreased (P<0.05) when they were fed with FSBM. The results showed that FSBM improved intestinal morphology and digestive enzyme activities in weaned piglets.

Identification of trait-improving quantitative trait loci for grain yield components from a dent corn inbred line in an advanced backcross BC2F2 population and comparison with its F2:3 population in popcorn

Normal maize germplasm could be used to improve the grain yield of popcorn inbreds. Our first objective was to locate genetic factors associated with trait variation and make first assessment on the efficiency of advanced backcross quantitative trait locus (AB-QTL) analysis for the identification and transfer of favorable QTL alleles for grain yield components from the dent corn inbred. A second objective was to compare the detection of QTL in the BC2F2 population with results using F(2:3) lines of the same parents. Two hundred and twenty selected BC2F2 families developed from a cross between Dan232 and an elite popcorn inbred N04 were evaluated for six grain yield components under two environments, and genotyped by means of 170 SSR markers. Using composite interval mapping (CIM), a total of 19 significant QTL were detected. Eighteen QTL had favorable alleles contributed by the dent corn parent Dan232. Sixteen of these favorable QTL alleles were not in the same or near marker intervals with QTL for popping characteristics. Six QTL were also detected in the F(2:3) population. Improved N04 could be developed from 210 and 208 families with higher grain weight per plant and/or 100-grain weight, respectively, and 35 families with the same or higher popping expansion volume than N04. In addition, near isogenic lines containing detected QTL (QTL-NILs) for grain weight per plant and/or 100-grain weight could be obtained from 12 families. Our study demonstrated that the AB-QTL method can be applied to identify and manipulate favorable QTL alleles from normal corn inbreds and combine QTL detection and popcorn breeding efficiently.

Identification of trait-improving quantitative trait loci for grain yield components from a dent corn inbred line in an advanced backcross BC2F2 population and comparison with its F2:3 population in popcorn

Normal maize germplasm could be used to improve the grain yield of popcorn inbreds. Our first objective was to locate genetic factors associated with trait variation and make first assessment on the efficiency of advanced backcross quantitative trait locus (AB-QTL) analysis for the identification and transfer of favorable QTL alleles for grain yield components from the dent corn inbred. A second objective was to compare the detection of QTL in the BC2F2 population with results using F(2:3) lines of the same parents. Two hundred and twenty selected BC2F2 families developed from a cross between Dan232 and an elite popcorn inbred N04 were evaluated for six grain yield components under two environments, and genotyped by means of 170 SSR markers. Using composite interval mapping (CIM), a total of 19 significant QTL were detected. Eighteen QTL had favorable alleles contributed by the dent corn parent Dan232. Sixteen of these favorable QTL alleles were not in the same or near marker intervals with QTL for popping characteristics. Six QTL were also detected in the F(2:3) population. Improved N04 could be developed from 210 and 208 families with higher grain weight per plant and/or 100-grain weight, respectively, and 35 families with the same or higher popping expansion volume than N04. In addition, near isogenic lines containing detected QTL (QTL-NILs) for grain weight per plant and/or 100-grain weight could be obtained from 12 families. Our study demonstrated that the AB-QTL method can be applied to identify and manipulate favorable QTL alleles from normal corn inbreds and combine QTL detection and popcorn breeding efficiently.

Lithium as adjuvant to radioiodine therapy in differentiated thyroid carcinoma: clinical and in vitro studies

OBJECTIVE

Lithium has been reported to increase radioactive iodine (RaI) doses in benign thyroid disease and in differentiated thyroid carcinoma (DTC). It is not known whether lithium influences the outcome of RaI therapy in DTC. We therefore studied the clinical effects of RaI without and with lithium carbonate in patients with proven metastatic DTC. Controversy also exists on the mechanism by which lithium increases RaI dose in DTC. We performed an in vitro study specifically aimed at examining the effects of lithium on the sodium iodide symporter (NIS).

DESIGN

In a clinical study, 12 patients were selected with metastases of DTC who had received previous RaI therapy without lithium (control) that had not influenced tumour progression, despite RaI accumulation in metastases. The patients received 1200 mg lithium carbonate/day followed by 6000 MBq RaI. Outcome parameters were RaI uptake, serum thyroglobulin (Tg) levels and radiological dimensions of metastases compared between RaI with lithium and control. In an in vitro study, iodide uptake was studied in the benign rat thyroid cell line FRTL-5, in the polarized non-thyroid MDCK cell line, stably transfected with human sodium iodide symporter (hNIS) to study the effects of lithium on NIS in a non-thyroid background, and the human follicular thyroid carcinoma cell line FTC133-hNIS to study lithium effects in a background of DTC. Lithium chloride (LiCl) was added in concentrations up to 2 mM for 0-48 h. Both steady-state iodide uptake (30 min) and initial rate (2 min) were studied using a specific activity of 100 mCi/mmol I, the latter experiment to determine lithium effects on substrate dependency. Iodide efflux studies were performed as well.

RESULTS

Despite an increased uptake of RaI in seven patients, no beneficial effect of RaI with lithium was observed on the clinical course as assessed by serum Tg measurements and radiographically. In the in vitro studies, no effects of LiCl on iodide uptake or efflux were observed.

CONCLUSIONS

The addition of lithium to RaI did not have any beneficial effects on the clinical course in 12 patients with metastatic DTC. No beneficial effects of lithium on iodide uptake were observed in vitro. Therefore, the clinical value of lithium in DTC remains subject to debate.

Recycling mineral nutrients to farmland via compost application

Increased cultivation of farmland has resulted in nutrient deficiency and consequently fertility degradation of soils. This research examined the application of composted wastes in terms of the feasibility and effectiveness of recycling plant essential minerals. Minerals in composts (derived from sewage sludge, livestock excrement, and municipal solid wastes, respectively) and in amended soils were observed. Ca/Mg ratios in amended soils and the effect of compost applications (mineral nutrients and heavy metals) on plant uptake were also studied. Results showed that composts, especially those made from sewage sludge and livestock excrement, were richer in mineral nutrients but also contained more heavy metals than untreated soil. The increase in some elements and plant-growth-essential Ca/Mg ratios were found in amended farmlands, implying that compost applications have made up for the nutrient deficiency and have adjusted chemical conditions of the soil. The soil contamination from heavy metals was noticeable. However, some results showed that the large existence of mineral nutrients and heavy metals in soils has caused no significant increase in the plant uptake of elements. The controlled composting process and farmland uses are believed necessary for reducing the heavy metal accumulation in agricultural plants.

Dysbaric osteonecrosis by X-ray and CT scan in Chinese divers

OBJECTIVE

To compare the results of X-ray and CT scan for dysbaric osteonecrosis in Chinese divers.

METHODS

Both shoulders, hips and knees of 66 asymptomatic divers with diving duration of more than one year were examined by X-ray and CT scan.

RESULTS

The most frequent locations of dysbaric osteonecrosis were the upper femurs, followed by the upper humerus, lower femurs and upper tibias, and the most frequent radiographic lesions were calcification spots and cystic changes. Of the lesions detected, 38% (27/71) and 42% (95/229) werejuxta-articular of the femoral and humeral heads by X-ray and CT respectively. The detection rates of dysbaric necrosis (juxta- and/or other lesions) of X-ray and CT scan were 42.4% (95% confidence interval: 30.5%-54.3%) and 81.8% (95% CI: 72.4%-91.2%) respectively (p<0.05). If CT scan was used as the gold standard, the sensitivity of X-ray was 100% and the specificity was 31.6%.

CONCLUSION

CT scan showed a higher detection rate of dysbaric necrosis than X-ray. We recommend that CT scan be used for early diagnosis of dysbaric osteonecrosis.

Distributions of iron, manganese, copper and zinc in various composts and amended soils

A detailed observation was conducted on Fe, Mn, Cu and Zn in the composts derived from seafood processing by-product, garbage, swine manure and sewage sludge, respectively, as well as in amended farmlands. All elements were at lower levels of total contents but a higher percentage of water-soluble and exchangeable forms in composted seafood processing by-product and composted garbage than in composted swine manure and composted sewage sludge. Total contents increased in the order: composted seafood processing by-product approximately composted garbage < composted swine manure < composted sewage sludge. The applications of composted seafood processing by-product and composted garbage have neither caused Fe, Mn, Cu and Zn accumulation nor changed their distribution in soils; while the application of composted swine manure has largely increased Cu and Zn contents in soils, mainly in organic matter-bound form, and that of composted sewage sludge increased Mn, Cu and Zn in soils mainly in carbonate-bond and Fe-Mn oxides-bound ones. Fe is an exception, its total contents in soils decreased with the applications of composts except for composted garbage. Also, the rainfall and irrigation were another two main factors that affected available elements in soils.

Alterations in g-protein-linked signal transduction in vascular smooth muscle in diabetes

The present studies were undertaken to determine the levels of stimulatory and inhibitory guanine nucleotide regulatory proteins (Gs and Gi respectively) and their relationship with adenylyl cyclase activity in aorta from 5-day streptozotocin-induced diabetic (STZ) rats. The levels of Gi alpha-2 as determined by immunoblotting techniques using AS/7 antibody were significantly decreased by about 60% in STZ as compared to control rats, whereas the levels of Gs alpha were not altered. In addition, the stimulatory effect of cholera toxin (CT) on GTP-sensitive adenylyl cyclase was not different in STZ as compared to control rats. On the other hand, the stimulatory effects of GTPgammaS, isoproterenol, glucagon, forskolin (FSK) and sodium fluoride on adenylyl cyclase were enhanced in STZ-rats. Furthermore, GTPgammaS inhibited FSK-stimulated adenylyl cyclase activity in a concentration-dependent manner (receptor independent functions of Gi) in control rats which was almost completely abolished in STZ rats. In addition, receptor-mediated inhibition of adenylyl cyclase by angiotensin II (AII), oxotremorine and atrial natriuretic peptide (ANP) was attenuated in STZ rats. These results suggest that the decreased expression of Gi alpha, but not of Gs alpha, may be responsible for the observed altered responsiveness of adenylyl cyclase to hormonal stimulation and inhibition in STZ-rats. It may thus be suggested that the decreased Gi activity may be one of the possible mechanisms responsible for the impaired vascular functions in diabetes.

[Computer-assisted acquisition and analysis of high-resolution spectrum]

Based on the unique characteristic of spectral line center in the whole spectrum and noise threshold, a computer approach and program for the determination of spectral line position and relative intensity automatically are presented in this paper. Exploring this approach and computer program, we pre-analyzed the partially overlapped 16 line TuFIR experiment spectra of CHF3. The results of line positions and intensities for these TuFIR spectra are in excellent agreement with the results by least-square fit with heavily manual inference. The accuracy and efficiency of this method and program will ensure their wide application in complex high-resolution molecular spectrum.

Isolation of an esterase-producing Trichosporon brassicae and its catalytic performance in kinetic resolution of ketoprofen

A yeast strain CGMCC 0574, identified as Trichosporon brassicae, was selected from 92 strains for its high (S) selectivity in the hydrolysis of ketoprofen ethyl ester. The effective strains of the microorganisms were isolated from soil samples with the ester as the sole carbon source. The ethyl ester proved to be the best substrate for resolution of ketoprofen among several ketoprofen esters examined. The resting cells of CGMCC 0574 could catalyze the hydrolysis of ketoprofen ethyl ester with an enantiomeric ratio of 44.9, giving (S)-ketoprofen an enantiomeric excess of 91.5% at 42% conversion.

Improved binding of a bivalent single-chain immunotoxin results in increased efficacy for in vivo T-cell depletion

Anti-CD3 immunotoxins exhibit considerable promise for the induction of transplantation tolerance in pre-clinical large animal models. Recently an anti-human anti-CD3epsilon single-chain immunotoxin based on truncated diphtheria toxin has been described that can be expressed in CHO cells that have been mutated to diphtheria toxin resistance. After the two toxin glycosylation sites were removed, the bioactivity of the expressed immunotoxin was nearly equal to that of the chemically conjugated immunotoxin. This immunotoxin, A-dmDT390-sFv, contains diphtheria toxin to residue 390 at the N-terminus followed by VL and VH domains of antibody UCHT1 linked by a (G(4)S)(3) spacer (sFv). Surprisingly, we now report that this immunotoxin is severely compromised in its binding affinity toward CD3(+) cells as compared with the intact parental UCHT1 antibody, the UCHT1 Fab fragment or the engineered UCHT1 sFv domain alone. Binding was increased 7-fold by adding an additional identical sFv domain to the immunotoxin generating a divalent construct, A-dmDT390-bisFv (G(4)S). In vitro potency increased 10-fold over the chemically conjugated immunotoxin, UCHT1-CRM9 and the monovalent A-dmDT390-sFv. The in vivo potency of the genetically engineered immunotoxins was assayed in the transgenic heterozygote mouse, tgepsilon 600, in which the T-cells express human CD3epsilon as well as murine CD3epsilon. T-cell depletion in the spleen and lymph node observed with the divalent construct was increased 9- and 34-fold, respectively, compared with the monovalent construct. The additional sFv domain appears partially to compensate for steric hindrance of immunotoxin binding due to the large N-terminal toxin domain.

Quantitative evaluation of synaptophysin-like immunoreactive nerve terminals or varicosities in anterior pituitary of normal and adrenalectomized rats

Our previous studies have demonstrated the presence of substantial amounts of peptidergic nerve fibres in the anterior pituitary of monkeys, dogs and rats. The nerve fibres increase in number following adrenalectomy and ovariectomy. Furthermore, typical synapses between nerve fibres and anterior pituitary glandular cells have been demonstrated in the dog and rat, strongly suggesting the existence of some direct neural regulation. However, it is difficult to evaluate the functional importance of synapses or nerve terminals in general, unless quantitative data can be provided. The present study therefore aimed to quantify the number of terminals or varicosities in the anterior pituitary of the rat and its changes following adrenalectomy. Nerve terminals or varicosities were identified by their synaptophysin (SYN)-like immunoreactivity. Under the light microscope, SYN-like immunoreactivity appeared mainly as dots, mostly among glandular cells, and some were found distributed along blood vessels. SYN-like immunoreactive dots were found under the electron microscope to be localized in the nerve terminals or varicosities. Synapse-like contracts between the nerve terminals or varicosities and the glandular cells could be identified. The number of SYN-like immunoreactive nerve terminals or varicosities was then counted under the light microscope. There were as many as 12424.2 +/- 2941.5 and 20700.4 +/- 6128 (mean +/- SD) nerve terminals or varicosities per anterior pituitary of normal and adrenalectomized rats, respectively. The increase in number following adrenalectomy was statistically significant. It is concluded that nerve fibres may play an important role in the regulation of the anterior pituitary.

Increase in cytochrome oxidase activity in regenerating nerve fibers of hemitransected spinal cord in the rat

We explored the possibility of cytochrome oxidase (CO) involvement in spinal cord regeneration in adult rats. The spinal cord was hemitransected at T9. After one month's survival, the animals were deeply anesthetized and perfused. The spinal cord segments including the lesion site were removed and sectioned horizontally for CO histochemistry. Under light microscope, a substantial number of CO-reactive nerve fibers and boutons were identified in the lateral funiculus adjacent to the lesion site. Under electron microscope, moderately to highly CO-reactive mitochondria could be seen within nerve fibers and boutons. Synaptic contacts were identified among them. The increase in CO activity in nerve fibers and boutons may indicate their high-energy demand for synaptic and spontaneous activity following spinal cord hemisection.

Distribution and colocalization of neurotransmitters and receptors in the pre-Bötzinger complex of rats

The pre-Bötzinger complex (PBC), thought to be the center of respiratory rhythm generation, is a cell column ventrolateral to the nucleus ambiguus. The present study analyzed its cellular and neurochemical composition in adult rats. PBC neurons were mainly oval, fusiform, or multipolar in shape and small to medium in size. Neurokinin-1 receptor, a marker of the PBC, was present in the plasma membrane of mostly medium and small neurons and their associated processes and boutons. Among neurons immunoreactive for different neurotransmitter or receptor candidates, various numbers were colocalized with neurokinin-1 receptor. The highest ratio was with nitric oxide synthase (52.72%), and the lowest was with glycine receptors (31.93%). Glutamic acid decarboxylase- and glycine transporter 2-immunoreactive boutons, as well as GABA(A) receptor-immunoreactive plasma membrane processes and boutons, were also identified in the PBC. PBC neurons exhibited different levels of cytochrome oxidase activity, indicating their various energy demands. Our results suggest that synaptic interactions within the PBC of adult rats involve a variety of neurotransmitter and receptor types and that nitric oxide may play an important role in addition to glutamate, GABA, glycine, and neurokinin.

[Effects of several different irritation factors on leukocytes adhesion in microvessels]

AIM

The interrelation of adhesion between leukocyte and endothelium was studied by several irritation factors.

METHODS

Leukocyte adhesion was observed by impulse electricity irritation, ischemia/reperfusion, endotoxin and IL-8 in venular of rat mesentery.

RESULTS

The results showed these irritation factors resulted in a significant increase in the number of leukocytes adhesion along the venular endothelium of rat mesentery. IL-8 leaded to the most increase of leukocytes adhesion. Especially treated by IL-8 for 30 minutes. The number of leukocytes adhesion of the others was approximately identical.

CONCLUSION

The study suggests that impulse electricity irritation, ischemia/reperfusion, endotoxin and IL-8 are able to induce leukocytes and endothelium adhesion, and IL-8 of them has the most effect.

Simultaneous determination of clozapine, norclozapine and clozapine-N-oxide in human plasma by high-performance liquid chromatography with ultraviolet detection

A reversed-phase high-performance liquid chromatographic (HPLC) method for the simultaneous determination of clozapine and its two major metabolites, norclozapine and clozapine-N-oxide in human plasma has been developed and validated. The isocratic HPLC assay uses a mobile phase consisting of an acetonitril-buffered aqueous solution containing 146 microL of triethylamine and 200 microL of 85% phosphoric acid, adjusted to pH 3.3 with 10% potassiumhydroxide solution (400:600, v/v) at a flow-rate of 0.8 ml/min and a Lichrospher 100 RP-18 reversed-phase column and UV detection at 215 nm. Doxepine was used as the internal standard. Mean recoveries for clozapine, norclozapine, clozapine-N-oxide and doxepine were 95%, 98%, 96% and 94%, respectively, whereas the respective mean repeatability coefficients of variation were 3.4%, 2.7%, 4.3% and 0.9%. Reproducibility coefficients of variation were 1.3%, 1.8%, 3.6% and 0.5%, respectively. The mean correlation coefficient for the linear calibration curve (n = 2) for clozapine and norclozapine at a concentration range of 100-1600 ng/mL was 0.9998 and 0.9997, respectively; for clozapine-N-oxide (20-200 ng/mL) it was found to be 0.9986. The lower limits of quantitation were 12.5 ng/mL, 10 ng/mL and 12.5 ng/mL for clozapine, norclozapine and clozapine-N-oxide, respectively.

Taxol-induced ceramide generation and apoptosis in human breast cancer cells

PURPOSE

Taxol has emerged as a valuable antimitotic chemotherapeutic agent, particularly in advanced breast and ovarian cancers. Although much is known about cytotoxic mechanisms, the effectiveness of Taxol cannot be solely explained by microtubular interaction. This study was undertaken to determine whether ceramide generation plays a role in Taxol-induced apoptosis.

METHODS

Hormone-independent MDA-MB-468 and hormone-dependent MCF-7 breast cancer cell lines were employed, and ceramide metabolism was characterized using [3H]palmitic acid as lipid precursor.

RESULTS

Exposure of cells to Taxol resulted in enhanced formation of [3H]ceramide. Ceramide increased nearly 2-fold in MDA-MB-468 cells exposed to 50 nM Taxol, and more than 2.5-fold in MCF-7 cells exposed to 1.0 microM Taxol. These concentrations mirrored the EC50 (amount of drug eliciting 50% cell kill) for Taxol in the two cell lines. Use of cell-permeable C6-ceramide as a medium supplement revealed that MDA-MB-468 cells were 20-fold more sensitive to ceramide than MCF-7 cells (P < 0.001). Ceramide was generated as early as 6 h after exposure to Taxol in MDA-MB-468 cells, whereas the earliest signs of apoptosis were detected 12 h after treatment, and by 24 h the apoptotic index was six times that of untreated cells. Both fumonisin B1, a ceramide synthase inhibitor, and L-cycloserine, a serine palmitoyltransferase inhibitor, blocked Taxol-induced ceramide generation, whilst sphingomyelin levels remained unchanged, indicating a de novo pathway of ceramide formation. L-Cycloserine reduced Taxol-induced apoptosis by 30% in MDA-MB-468 cells and totally blocked Taxol-induced apoptosis in MCF-7 cells.

CONCLUSIONS

These results suggest that Taxol-induced apoptosis is, in part, attributable to ceramide and sphingoid bases. This is of relevance to drug mechanism studies, as ceramide is a known messenger of apoptosis. Clinical use of Taxol with ceramide-enhancing agents may maximize cytotoxic potential.

Differential regulation of heterodimerization by 1alpha,25-dihydroxyvitamin D(3) and its 20-epi analog

Twenty-epi analogs of 1alpha,25-dihydroxyvitamin D(3) (1alpha,25(OH)(2)D(3)) are 100-1000 times more potent transcriptionally than the natural hormone. To determine to what extent this enhanced activity is mediated through modulation of the dimerization process, we performed quantitative dimerization assays with in vitro translated vitamin D receptor (ivtVDR) and fusion proteins containing glutathione-S-transferase (GST) and either the ligand-binding domain of VDR (GST-VDR) or retinoid X receptor (RXR)alpha (GST-RXR). We found that VDR did not form homodimers in either the presence or absence of ligand, but heterodimerization of the ligand-binding domains of RXRalpha and VDR was primarily deltanoid-dependent. The ED(50) for induction of heterodimerization was 1-2 x 10(-)(9) M for 1alpha,25(OH)(2)D(3) and 0.5 x 10(-)(11) M for 20-epi 1alpha,25(OH)(2)D(3). Mutations in VDR's activation function 2 domain (AF-2) diminished the abilities of 1alpha,25(OH)(2)D(3) to induce a protease-resistant conformation and heterodimerization. These mutations changed neither the potency of 20-epi-1alpha,25(OH)(2)D(3) to induce protease-resistant conformation nor its potency to induce dimerization. Mutations in heptad 9/helix 10 abolished the ability of both 1alpha,25(OH)(2)D(3) and the 20-epi analog to induce dimerization, but not their potency to fold VDR into a protease-resistant conformation. We hypothesize that both the hormone and the analog stabilize receptor conformations that expose VDR's dimerization interface, and that interfaces exposed by these ligands are probably not significantly different. However, the mechanisms by which the two ligands expose the dimerization interface are different with respect to participation of the AF-2 domain.

Ceramide glycosylation potentiates cellular multidrug resistance

Ceramide glycosylation, through glucosylceramide synthase (GCS), allows cellular escape from ceramide-induced programmed cell death. This glycosylation event confers cancer cell resistance to cytotoxic anticancer agents [Liu, Y. Y., Han, T. Y., Giuliano, A. E., and M. C. Cabot. (1999) J. Biol. Chem. 274, 1140-1146]. We previously found that glucosylceramide, the glycosylated form of ceramide, accumulates in adriamycin-resistant breast carcinoma cells, in vinblastine-resistant epithelioid carcinoma cells, and in tumor specimens from patients showing poor response to chemotherapy. Here we show that multidrug resistance can be increased over baseline and then totally reversed in human breast cancer cells by GCS gene targeting. In adriamycin-resistant MCF-7-AdrR cells, transfection of GCS upgraded multidrug resistance, whereas transfection of GCS antisense markedly restored cellular sensitivity to anthracyclines, Vinca alkaloids, taxanes, and other anticancer drugs. Sensitivity to the various drugs by GCS antisense transfection increased 7- to 240-fold and was consistent with the resumption of ceramide-caspase-apoptotic signaling. GCS targeting had little influence on cellular sensitivity to either 5-FU or cisplatin, nor did it modify P-glycoprotein expression or rhodamine-123 efflux. GCS antisense transfection did enhance rhodamine-123 uptake compared with parent MCF-7-AdrR cells. This study reveals that GCS is a novel mechanism of multidrug resistance and positions GCS antisense as an innovative force to overcome multidrug resistance in cancer chemotherapy.

[The trends and preventive strategies of esophageal cancer in high-risk areas of Taihang Mountains, China]

OBJECTIVE

To analyze and predict the trends of incidence and mortality rates of esophageal cancer in areas of Taihang Mountains, and explore the strategies for facilitating the reduction of the incidence and mortality of esophageal cancer.

METHODS

The data were collected from Linxian and Cixian Counties registries between 1988-1997. The trends of the incidence and mortality rates for esophageal cancer had been fitted and predicted by the model of BP (Back Propagation) Neural Networks. Then Linqi Xiang in Linxian County was taken as an example, to determine the power for reducing incidence and mortality of esophageal cancer using endoscopic technology as an early detection and treatment method.

RESULTS

There were slowly declining trends for both incidence and mortality rates during past 10 years in Taihang Mountains. The predicting rates of the esophageal cancer incidence in 2,002 are 115. 70/100,000 for male and 79.88/100,000 for female; mortality rates are 94.00/100,000 and 56.29/100,000 respectively. Both incidence and mortality rates a still in high level. But when using endoscopic technology as an early detection and treatment method, the incidence rate is nearly 1/3 of a control group and the power is 88.30% at the end of eight years. The mortality rate is 1/4 of the control group and power is 89.44% after five years intervention (both powers based on 0.05 significant levels).

CONCLUSIONS

The incidence and mortality rates for esophageal cancer are still on high levels in Taihang Mountains. We should continue to enhance our preventive effort there. After using endoscopic technology as an early detection and treatment method, the incidence and mortality rates will be decreased markedly during 5 to 8 years. It is recommended to implement a large-scale secondary prevention strategy in these areas.

[Vacuole formation and endothelial damage in microvessels after ischemia reperfusion]

AIM

Damage of endothelial cells and adhesion of leukocytes and platelets were studied in rat mesentery microvessels after ischemia reperfusion.

METHODS

The model was made by losing blood and reperfusion from carotid artery in rat. Changes of mesentery microvessels were observed by high magnify microscope.

RESULTS

Leukocytes and platelets adhesions were found in venules and co capillaries 1-3 hours after ischemia reperfusion. Endothelial cells were edema and vascular walls were thickening. Vacuoles formed in intracytoplasm of some vascular endothelium and some bigger endothelial vacuoles prominence toward the luminal surface. Vacuoles liked circle shape and the diameter was 10-30 microm. More vacuoles were found in arterioles, even there were several vacuoles in a arteriole. The biggest vacuole almost occupied 2/3 of vascular lumen.

CONCLUSION

Edema and vacuole formation in vascular endothelium indicate that endothelial cells are injured seriously after ischemia reperfusion.

Developmental study of cytochrome oxidase activity in the brain stem respiratory nuclei of postnatal rats

We utilized cytochrome oxidase (CO) as a marker of neuronal functional activity to examine metabolic changes in brain stem respiratory nuclei of rats from newborn to 21 day of age. The pre-Bötzinger complex (PBC), upper airway motoneurons of nucleus ambiguus (NA(UAM)), ventrolateral nucleus of solitary tract (NTS(VL)), and medial and lateral parabrachial nuclei (PB(M) and PB(L), respectively) were examined at postnatal days (P) 0, 1, 2, 3, 4, 5, 7, 14, and 21. CO histochemistry was performed, and the intensity of CO reaction product was quantitatively analyzed by optical densitometry. In addition, CO histochemistry was combined with neurokinin-1 receptor (NK1R) immunogold-silver staining to doubly label neurons of PBC in P14 animals. The results showed that levels of CO activity generally increased with age in all of the nuclei examined. However, a significant decrease was found in NA(UAM) at P3 (P < 0.01), and a distinct plateau of CO activity was noted at P3 in PBC and at P3 and P4 in NTS(VL), PB(M), and PB(L). Of the neurons examined in PBC, 83% were doubly labeled with CO and NK1R. Of these, CO activity was high in 33.9%, moderate in 27.3%, and light in 38.8% of neurons, suggesting different energy demands in these metabolic groups that may be related to their physiological or synaptic properties. The transient decrease or plateau in CO activity at P3 and P4 implies a period of synaptic adjustment or reorganization during development, when there may be decreased excitatory synaptic drive or increased inhibitory synaptic drive, or both, in these brain stem respiratory nuclei. The adjustment, in turn, may render the system less responsive to respiratory insults. This may bear some relevance to our understanding of pathological events during postnatal development, such as occurs in sudden infant death syndrome.

The sulfonylurea glimepiride regulates intracellular routing of the insulin-receptor complexes through their interaction with specific protein kinase C isoforms

Sulfonylureas may stimulate glucose metabolism by protein kinase C (PKC) activation. Because interaction of insulin receptors with PKC plays an important role in controlling the intracellular sorting of the insulin-receptor complex, we investigated the possibility that the sulfonylurea glimepiride may influence intracellular routing of insulin and its receptor through a mechanism involving PKC, and that changes in these processes may be associated with improved insulin action. Using human hepatoma Hep-G2 cells, we found that glimepiride did not affect insulin binding, insulin receptor isoform expression, and insulin-induced receptor internalization. By contrast, glimepiride significantly increased intracellular dissociation of the insulin-receptor complex, degradation of insulin, recycling of internalized insulin receptors, release of internalized radioactivity, and prevented insulin-induced receptor down-regulation. Association of PKC-betaII and -epsilon with insulin receptors was increased in glimepiride-treated cells. Selective depletion of cellular PKC-betaII and -epsilon by exposure to 12-O-tetradecanoylphorbol-13-acetate (TPA) or treatment of cells with PKC-betaII inhibitor G06976 reversed the effect of glimepiride on intracellular insulin-receptor processing. Glimepiride increased the effects of insulin on glucose incorporation into glycogen by enhancing both sensitivity and maximal efficacy of insulin. Exposing cells to TPA or G06976 inhibitor reversed these effects. Results indicate that glimepiride increases intracellular sorting of the insulin-receptor complex toward the degradative route, which is associated with both an increased association of the insulin receptor with PKCs and improved insulin action. These data suggest a novel mechanism of action of sulfonylurea, which may have a therapeutic impact on the treatment of type 2 diabetes.

The relationship between social support and well-being of rural elderly women

The purpose of this study is to examine the relationship between social support and well-being of rural elderly women. A sample of 284 women aged 60 and older (M = 69.12, SD = 6.40) in a rural area of southern Taiwan completed all interview questions. The Chinese versions of the Personal Resource Questionnaire (PRQ) and the Positive Affect and Negative Affect Scale (PANAS) were used to measure social support and well-being. Content validity of the Chinese versions of the instruments was estimated as satisfactory. The alpha reliability coefficients were .86 for the entire PRQ-85 Part 2 and from .65 to .78 for the subscales. The alpha reliability coefficients were .85 and .65 for the PA subscale and NA subscale respectively. Pearson correlation coefficients were used to examine the relationship between social support and well-being. The findings demonstrated that not only the entire social support but also its five dimensions were positively correlated with positive affect (r ranged from .24 to .48, p < .01) and were inversely correlated with negative affect (r ranged from -.15 to -.21, p < .05 or .01). A substantive intervention design may help verify the effectiveness of social support on elderly women's positive affect and negative affect. Using social support as a strategy to promote these women's well-being, therefore, should be the subject of future study.

Regulation of ligand-induced heterodimerization and coactivator interaction by the activation function-2 domain of the vitamin D receptor

Twenty-epi analogs of 1alpha,25-dihydroxyvitamin D3 (1,25D3) are 100-1000 times more potent transcriptionally than the natural hormone. To determine whether this enhanced activity is mediated through modulation of the dimerization process or through interaction with coactivators, we performed quantitative protein-protein interaction assays with in vitro translated vitamin D receptor (ivtVDR) and fusion proteins containing glutathione-S-transferase (GST) and either the ligand-binding domain of retinoid X receptor (RXRalpha), or the nuclear receptor-interacting domain of the steroid receptor coactivator 1 (SRC-1), or the glucocorticoid receptor-interacting protein 1 (GRIP-1). We found that heterodimerization of the ligand-binding domains of RXRalpha and VDR was primarily deltanoid dependent as was the interaction of VDR with the SRC-1 or with GRIP-1. The ED50 for induction of heterodimerization was 2 nM for 1,25D3 and 0.05 nM for 20-epi-1,25D3. However, the ED50 for induction of VDR interaction with SRC-1 was similar for both 1,25D3 and the 20-epi analog (ED50 = 0.7-1.0 nM) as was the ED50 for ligand-mediated interaction of VDR with GRIP-1 (ED50 = 0.1-0.3 nM). Mutations in heptad 9 diminished both 1,25D3 and the 20-epi analog-mediated dimerization, without changing binding of these ligands to VDR. Mutations in VDR's activation function 2 (AF-2) domain/helix 12 residues diminished the ability of 1,25D3 to induce heterodimerization and interaction with SRC-1. These mutations did not change the ability of 20-epi-1,25D3 to induce dimerization but did diminish its ability to induce interaction with SRC-1. We hypothesize that both the hormone and the analog stabilize receptor conformations that expose VDR's functional interfaces. The mechanisms by which the two ligands expose these functional interfaces differ with respect to participation of the AF-2 domain.

A mammalian cytochrome fused to a chloroplast transit peptide is a functional haemoprotein and is imported into isolated chloroplasts

The small subunit of ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco) is a major chloroplast stromal protein that is cytosolically synthesized as a precursor with an N-terminal extension, known as the transit sequence or transit peptide (Tp). The Tp is essential for the post-translational uptake of the precursor by the chloroplast. The Tp is thought to influence the conformation of the precursor protein and to facilitate polypeptide translocation across the chloroplast envelope barrier via a Tp-selective translocon. To address these issues we have devised a novel strategy to generate substrate amounts of a chloroplast targeting sequence as a fusion with the chromogenic globular domain of cytochrome b(5) (Cyt). The chimaeric protein is an ideal probe for investigating the conformation of a preprotein and events surrounding protein import into isolated chloroplasts. The Cyt of liver endoplasmic reticulum was fused at its N-terminus with the Tp of the small subunit of Rubisco of Pisum sativum (pea). To enhance its production by clearance from the cytoplasm of Escherichia coli, the chimaera was engineered by further N-terminal linkage of a prokaryotic secretory signal. Expression of this tripartite fusion resulted in mg quantities of the signal sequence-processed Tp-Cyt protein, which was eventually targeted to the membranes. The chromogenic nature of the chimaera and its localization to the bacterial membrane facilitated the biochemical isolation of the precursor in a soluble and functional form. The purified preprotein displayed spectral and enzymic properties that were indistinguishable from the native parental Cyt, implying an absence of observable influence of the Tp on the conformation of the haemoprotein. The chimaeric precursor was imported into the stroma of the isolated chloroplasts in a dose-dependent manner. Import was also strongly dependent upon exogenously supplied ATP. The stromally imported chimaeric precursor protein was processed to a size characteristic of Cyt.