[A prospective cohort study on effects of levonorgestrel-releasing intrauterine system for adenomyosis with severe dysmenorrhea]

OBJECTIVE

To investigate treatment effects of levonorgestrel-releasing intrauterine system (LNG-IUS) for adenomyosis with severe dysmenorrhea in a prospective cohort study.

METHODS

From December 2006 to December 2014, patients of symptomatic adenomyosis diagnosed by transvaginal ultrasound in outpatient or inpatient clinics of Peking Union Medical College Hospital were given the treatment of LNG-IUS. Before and after placement of LNG-IUS, all the patients' parameters were recorded prospectively, including symptoms and scores of dysmenorrhea, menstruation scores, biochemical indicators, physical parameters, carrying status of LNG-IUS, menstruation patterns and adverse effects. Changes of scores and patterns of pain during follow-up were analyzed.

RESULTS

Totally 1 100 women meets inclusion criteria, among which 640 cases (58.18%, 640/1 100) had severe dysmeorrhea, with median follow-up period of 35 months (range 1-60 months), and accumulative carrying rate of 65% at 60 months follow-up. After placement of LNG-IUS, scores of pain and ratio of severe dysmenorrhea had decreased significantly compared with baselines (all P<0.01), the scroes of visual analog scale (VAS) were 8.1±0.9, 5.5±2.4, 4.6±2.4, 3.3±2.2, 2.2±2.1, 2.2±1.8, 1.4±1.6 and 1.3±1.3 at 0, 3, 6, 12, 24, 36, 48 and 60 months respectively. During 36 months after placement of LNG-IUS, scores of pain had improved significantly compared with preceding period (all P<0.01). We found no universal dependent factors predicting improvement of pain, which was neither relevant with simultaneous changes of menstruation patterns nor adverse effects (all P>0.05).

CONCLUSION

LNG-IUS is effective for adenomyosis of severe dysmenorrhea. Improvement of pain is independent on patients characters, menstruation patterns or adverse effects.

Electronic transport in NbSe₂ two-dimensional nanostructures: semiconducting characteristics and photoconductivity

The electronic transport properties of two-dimensional (2D) niobium diselenide (NbSe2) layer materials with two-hexagonal single-crystalline structures grown by chemical vapor transport were investigated. Those NbSe2 nanostructures isolated simply using mechanical exfoliation were found to exhibit lower conductivity and semiconducting properties, compared with their bulk metallic counterparts. Benefiting from lower dark conductivity, NbSe2 nanoflakes exhibit a remarkable photoresponse under different wavelengths and intensity excitations. The photocurrent responsivity and photoconductive gain can reach 3.8 A W(-1) and 300, respectively; these values are higher than those of graphene and MoS2 monolayers and are comparable with those of GaS and GaSe nanosheets. The presence of electron trap states at the surface was proposed as an explanation for the reduced dark conductivity and enhanced photoconductivity in the 2D NbSe2 nanostructures. This work identifies another possibility for the application of a metallic layer material as an optoelectronic component in addition to an ultrathin transparent conducting material.

Association Between Smoking and p53 Mutation in Oesophageal Squamous Cell Carcinoma: A Meta-analysis

AIMS

Several studies have evaluated the association between smoking and p53 mutation in oesophageal squamous cell carcinoma (ESCC), but the conclusions are inconsistent. The aim of the present study was to carry out a meta-analysis evaluating the relationship between smoking and p53 mutation in patients with ESCC.

MATERIALS AND METHODS

Eligible studies were identified through searches in PubMed and EMBASE. The odds ratio with 95% confidence interval was used to assess the association. In total, 20 studies were identified that met the selection criteria; these studies were analysed using STATA 12.0 software.

RESULTS

The 20 studies identified comprised 1524 ESCC patients, of whom 72.97% were smokers and 27.03% were non-smokers. The pooled odds ratio of p53 mutation in ESCC for any cigarette smoking versus no smoking was 1.28 (95% confidence interval=0.88-1.88). The estimated odds ratios were 1.06 (95% confidence interval=0.56-2.00, based on five studies, 129 light smokers and 70 non-smokers) for light smoking and 2.01 (95% confidence interval=1.12-3.60, based on five studies, 223 heavy smokers and 73 non-smokers) for heavy smoking.

CONCLUSION

The results of our meta-analysis indicate an overall positive relationship between heavy smoking and p53 mutation in ESCC. Heavy smokers with ESCC have a higher risk for p53 mutation than non-smokers. Large-scale clinical studies are still needed to draw a more precise conclusion.

Molecular characterization, phylogenetic analysis and expression profiling of myoglobin and cytoglobin genes in response to heat stress in channel catfish Ictalurus punctatus

To understand the function of myoglobin (Mb) and cytoglobin (Cygb) in channel catfish Ictalurus punctatus in response to heat stress, mb and cygb genes were identified and characterized in this study. These genes were widely expressed in all the tested tissues, but strong tissue preferences were observed, with the mb gene being expressed most highly in the heart, cygb1 most highly expressed in the intestine and cygb2 most highly expressed in the brain. After heat-stress challenge, mb and cygb genes were up-regulated in almost all tested tissues. In general, such up-regulation was more dramatic in the tolerant group than in the intolerant group, suggesting that higher expression of mb and cygb genes contributed to greater tolerance of I. punctatus to heat stress.

Large in-plane deformation of RuO6 octahedron and ferromagnetism of bulk SrRuO3

SrRuO3 is a ferromagnetic metal with several unusual physical properties such as zero thermal expansion below Tc, so-called Invar behavior. Another anomalous feature is that the a-axis lattice constant is larger than the b-axis lattice constant, a clear deviation from the predictions of the Glazer structural description with rigid RuO6 octahedron motion. Using high resolution neutron diffraction techniques, we show how these two structural anomalies arise from the irregular in-plane deformation, i.e. plastic behavior of the RuO6 octahedron, a weak band Jahn-Teller distortion. We further demonstrate that the ferromagnetic instability of SrRuO3 is related to the temperature-induced localization of Ru 4d bands.

Meta-analysis of temporary ileostomy versus colostomy for colorectal anastomoses

BACKGROUND/AIMS

Defunctioning stoma is a common surgical procedure, it is now generally acknowledged that defunctioning stoma significantly reduce the rates of complications in colorectal surgery, but the choice of temporary ileostomy or temporary colostomy for defunctioning colorectal anastomoses remains controversial. This meta-analysis evaluated two types of defunctioning stoma to determine whether one is superior to the other.

METHODOLOGY

Studies and relevant literatures comparing temporary ileostomy with temporary colostomy for defunctioning colorectal anastomoses were searched though PubMed, Embase and The Cochrane Library. The rates of complications were pooled and compared using a meta-analysis. The risk ratios were calculated with 95% confidence intervals to evaluate the safety and efficacy of each technique.

RESULTS

Five randomized controlled trials and seven non-randomized studies were included, with 1687 patients in total. The meta-analysis of the RCTs demonstrated a lower risk of stoma prolapse (RR 0.15; 95% CI: 0.04-0.48, p = 0.001) in the temporary ileostomy group. Meta-analysis of the non-randomized studies showed a lower risk of stoma prolapse (RR 0.26; 95% CI 0.10-0.67, p = 0.005) and wound infection after stoma closure (RR 0.28; 95% CI 0.5-0.52, p < 0.0001) in the temporary ileostomy group. No other statistically significant difference was observed for complications.

CONCLUSIONS

Each type of defunctioning stoma has its advantages and disadvantages, and there is not a strong evidence for the superiority of one temporary stoma over another for colorectal anastomoses. According to this, large scale RCTs and high quality studies are needed to conduct.

First evidence for the contribution of the genetic variations of BRCA1-interacting protein 1 (BRIP1) to the genetic susceptibility of cervical cancer

BRIP1 (BRCA1-interacting protein 1), a DNA-dependent ATPase and a DNA helicase, is critical for BRCA-associated DNA damage repair functions, and may be involved in the development of cervical cancer. Genetic markers in different regions of the BRIP1 gene have a plausible role in modulating the risk of cervical cancer. In this study, we evaluate the association between the BRIP1 variations and the risk of cervix cancer. We examined the potential association between cervical cancer and eighteen single nucleotide polymorphisms (SNPs, rs2048718, rs16945692, rs4968451, rs6504074, rs4988344, rs8077088, rs10515211, rs9897121, rs9906313, rs2159450, rs4986764, rs11871785, rs4986763, rs11079454, rs7213430, rs34289250, rs4988345 and rs12937080) of the BRIP1 gene using the MassARRAY system. The participants enrolled in this study included 298 patients with cervical cancer and 286 healthy women as the healthy controls from a Chinese Han population. The results showed that rs16945692 (intron 1), rs4968451 (intron 4), rs4986764 (exon 18) and rs7213430 (3'UTR) were significantly associated with cervical cancer (P<0.05). Furthermore, strong linkage disequilibrium (LD) was observed in three blocks (D'>0.9), and significantly more T-A-C-A haplotypes (block 1) (P=0.001) were found in the patients with cervical cancer. Significantly higher frequencies of C-A-T haplotypes (block 2) (P=0.018) and A-A haplotypes (block 3) (P=0.009) were detected in the healthy controls than in the patients with cervical cancer, suggesting that they may show protective effects against cervical cancer. These findings point to a role for the BRIP1 gene polymorphisms in cervical cancer in a Chinese Han population, and may be informative for future genetic or biological studies on cervical cancer.

An SNP in the MyoD1 gene intron 2 associated with growth and carcass traits in three duck populations

Myogenic differentiation 1 (MyoD1) genes belong to the MyoD gene family and play key roles in growth and muscle development. This study was designed to investigate the effects of variants in the MyoD1 gene on duck growth and carcass traits. Three duck populations (Cherry Valley, Jingjiang, and Muscovy) were sampled, their growth and carcass traits were measured, and they were genotyped using the PCR-RFLP method. The results showed one novel polymorphism, an alteration in intron 2 of the MyoD1 gene (A to T). It was associated with the traits of weight at 8 weeks, carcass weight, breast muscle weight, leg muscle weight, eviscerated percentage, percentage of leg muscle weight, dressing percentage, and lean meat percentage. This alteration in intron 2 of MyoD1 may be linked with potential major loci or genes affecting some growth and carcass traits.

Cryosurgery for treatment of subcutaneously xenotransplanted tumors in rats and its effect on cellular immunity

Cryosurgery has shown encouraging therapeutic effects on some solid tumors but its effect on the cellular immunity remains unclear. We developed a subcutaneously xenotransplanted tumor model in SD rats to directly evaluate the immune response by detecting the serum cytokine levels, T-cell responses to tumor derived antigens, and the cytolytic activity of peripheral blood mononuclear cells against the W256 cancer line with apoptosis of cells being detected using TUNEL method. 66 SD rats were divided into 2 groups with group A having 36 rats and group B having 30 rats. 30 rats in group B were equally divided into 3 groups, tumor group B, cryosurgery group B and surgery group B, with 10 rats each. 36 rats in group A were equally divided into 2 groups, cryosurgery group A and tumor group A and treatment was done accordingly. The results showed that cryosurgery induced not only destruction of the tumor cells but also cell apoptosis around the cryosurgery foci. The apoptosis ratio reached the peak 12 h after cryosurgery, with an apoptosis rate of (68.28 ± 7.85)% .Compared with surgical resection that caused significant reduction in CD31 and CD41 cell percentages, cryosurgery resulted in significantly increased percentages of CD31 and CD41 cells (P < 0.05) with a relative increase of the CD41/CD81 cell ratio. However, sIL-2R level of peripheral blood of rats in cryosurgery group which decreased more rapidly than that in surgery group over time was significantly different 3 and 5 weeks after treatment compared to surgery group (P < 0.01). Moreover, cytotoxicity of mononuclear cell was significantly enhanced after cryosurgery, which is significantly higher in cryosurgery group (P = 0.05). These results demonstrate that in addition to tumor cell destruction, cryosurgery also results in enhanced cellular immunity and antitumor immune response of the rats with subcutaneously xenotransplanted tumor, suggesting the great potential of argon-helium cryosurgery in clinical management.

The roles of Dippu-allatostatin in the modulation of hormone release in Locusta migratoria

Dippu-allatostatins (ASTs) have pleiotropic effects in Locusta migratoria. Dippu-ASTs act as releasing factors for adipokinetic hormone I (AKH I) from the corpus cardiacum (CC) and also alter juvenile hormone (JH) biosynthesis and release from the corpus allatum (CA). Dippu-AST-like immunoreactivity is found within lateral neurosecretory cells (LNCs) of the brain and axons within the paired nervi corporis cardiaci II (NCC II) to the CC and the CA, where there are extensive processes and nerve endings over both of these neuroendocrine organs. There was co-localization of Dippu-AST-like and proctolin-like immunoreactivity within these regions. Dippu-ASTs increase the release of AKH I in a dose-dependent manner, with thresholds below 10(-11)M (Dippu-AST 7) and between 10(-13) and 10(-12)M (Dippu-AST 2). Both proctolin and Dippu-AST 2 caused an increase in the cAMP content of the glandular lobe of the CC. Dippu-AST 2 also altered the release of JH from the locust CA, but this effect depended on the concentration of peptide and the basal release rates of the CA. These physiological effects for Dippu-ASTs in Locusta have not been shown previously.

A putative farnesoic acid O-methyltransferase (FAMeT) orthologue in Drosophila melanogaster (CG10527): relationship to juvenile hormone biosynthesis?

Juvenile hormones (JHs) are key regulators of both metamorphosis and adult reproductive processes. Farnesoic acid O-methyltransferase (FAMeT) is thought to be an important enzyme in the JH biosynthetic pathway, catalyzing methylation of farnesoic acid (FA) to methyl farnesoate (MF). Previous evidence in other insects suggested that FAMeT is rate limiting and regulated by a neuropeptide family, the allatostatins. A full-length cDNA encoding a 296 amino acid putative FAMeT has been isolated. A recombinant (r)FAMeT was cloned, expressed and a specific antiserum generated. rFAMeT was assayed for enzymatic activity using a radiochemical assay. In this assay, no activity was detected either with rFAMeT alone or when added to a corpus allatum CA extract. Immunohistochemical analysis was used to confirm the presence of FAMeT in the CA of Drosophila melanogaster ring gland. Analysis of MF, JHIII and JHB3 release in wild type and mutant stocks in the presence and absence of Drome AST (PISCF-type) suggest that Drosophila FAMeT has little if any effect on sesquiterpenoid biosynthesis. Drome AST appears to have a select effect on JH bisepoxide biosynthesis and not MF or JHIII. Additional analysis of MF, JHIII and JHB3 release in strains with a deficiency or decrease of FAMeT compared to wild type shows no significant decrease in MF, JHIII or JH bisepoxide synthesis. Deficiency strains that reduce the level of FAMeT showed reduced longevity relative to wildtype but this result may be due to other genetic influences.

ATP7B antisense oligodeoxynucleotides increase the cisplatin sensitivity of human ovarian cancer cell line SKOV3ipl

The objective of this study was to investigate the effect of ATP7B antisense oligodeoxynucleotides (ASODNs) on regulating the sensitivity to cisplatin in ovarian carcinoma cell line SKOV3ip1. The ATP7B ASODNs and the corresponding sense oligodeoxynucleotide (SODN) as control were transfected into SKOV3ip1 cells by lipofectamine-2000. The changes of ATP7B were detected by reverse transcription-polymerase chain reaction, flow cytometry, and Western blotting. The survival rate of the SKOV3ip1 cells was assessed by MTT assay. Compared with nontransfected cell, the transfer of ASODN/lipofectin (LF) into SKOV3ip1 cells resulted in (1) 73.70% and 48.30% reduction of ATP7B in messenger RNA and protein, respectively, (2) an obviously decreased intracellular fluorescence intensity from 79.42 to 50.87 (P < 0.01), and (3) a decreased IC(50) value for cisplatin from 126.63 to 80.90 micromol/L (P < 0.01), while no significant changes were detected for groups treated with SODN/LF and LF only. ASODN transfection can inhibit the expression of ATP7B and increase the cisplatin sensitivity in SKOV3ip1 cells.

Laparoscopically assisted sigmoid colon vaginoplasty in women with Mayer-Rokitansky-Kuster-Hauser syndrome: feasibility and short-term results

OBJECTIVES

To evaluate the technical feasibility and anatomical and functional outcomes of laparoscopically assisted sigmoid colon vaginoplasty (LASV) in women with Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome.

DESIGN

A retrospective review of prospectively collected data.

SETTING

Shanghai First People's Hospital, Shanghai Jiao Tong University.

POPULATION

Twenty-six women with MRKH syndrome.

METHODS

A record was made of mean operating time, length of hospital stay, perioperative complications and the anatomical and functional outcomes of surgery.

MAIN OUTCOME MEASURES

The perioperative results, complications and anatomical and functional outcomes of LASV (with median 20 months follow up, range 5-48 months).

RESULTS

The mean operating time and hospital stay were 238 minutes and 9.8 days, respectively. The mean fall in haemoglobin was 2.0 g/dl. The only significant perioperative complications were one case with blood transfusion and three cases with infection (one with urinary tract and two with adjunctive incision). A functioning vagina 10 to 15 cm in length and 4 cm in width was created in all women. Introital stenosis occurred in only two women (2 months later). Twenty-two women subsequently had intercourse and 20 women (91%) were satisfied with the surgery and subsequent sexual activity.

CONCLUSIONS

LASV is an effective approach for women with MRKH syndrome. Both the anatomical and functional outcomes are satisfactory.

In vitro induction of tetraploid plants from diploid Zizyphus jujuba Mill. cv. Zhanhua

Tetraploid plants of Zizyphus jujuba Mill. cv. Zhanhua were obtained with in vitro colchicine treatment. Shoot tips from in vitro-grown plants were treated with five different concentrations of colchicine (0.01, 0.03, 0.05, 0.1, 0.3%) in liquid MS medium (Murashige and Skoog 1962), and shaken (100 rpm) at 25 degrees C in darkness for 24, 48, 72 or 96 h, respectively. Tetraploids were obtained at a frequency of over 3% by using 0.05% colchicine (48 h, 72 h) and 0.1% colchicine (24 h, 48 h) treatment as determined by flow cytometry. Cytological and morphological evidence confirmed the results of flow cytometric analysis. The chromosome number of diploid plants was 24 and that of tetraploid plants was 48. The stomata sizes of tetraploid plants were significantly larger than those of diploid plants, while the frequency of stomata were reduced significantly. Similarly, the chloroplast number of guard cells of tetraploid plants increased significantly. The selected tetraploid plants were grafted onto mature trees of Z. jujuba Mill. cv. Zhanhua in the field, resulted in thicker stems, rounder and succulent leaves, larger flowers and a delay in florescence time (3-4 days later) than diploid plants.

Preparation of new amino acid complex nanoparticles of bismuth and leucine

The new amino acid complex nanoparticles of bismuth and leucine can be prepared very easily by a room temperature solid-solid reaction. The various characterizations indicate that the formula of the complex is BiCl[(CH(3))(2)CHCH(2)CHNH(2)COO](2)1.5H(2)O. The crystal structure of the solid complex belongs to monoclinic system with the lattice parameters: a = 1.6036 nm, b = 1.9903 nm, c = 2.1979 nm and beta=108.06 degrees . The new solid complex is nanoparticles with average size about 80 nm.

An efficient adventitious shoot regeneration system for Zhanhua winter jujube (Zizyphus jujuba Mill.) using leaf explants

The direct induction of adventitious shoots from leaf explants obtained from adult plants of Zhanhua winter jujube, an elite variety of Zizyphus jujuba Mill., is reported. The percentage of leaf explants producing shoots and the average number of shoots per explant were significantly improved when 10-day-old leaves were explanted onto Woody Plant Medium and maintained initially in the dark. The plant growth regulator thidiazuron (TDZ) was effective in stimulating shoot regeneration from leaf explants of Zhanhua winter jujube. The highest efficiency of shoot formation was observed with a 20-day culture in the dark on WPM containing 4.54 microM TDZ and 2.85 microM indoleacetic acid (IAA). The regenerated shoots were transferred to MS medium containing 0.89 microM benzyladenine and 5.77 microM gibberellic acid for growth. When the shoots were about 2 cm in height, they were transferred to Nitsch medium supplemented with 1.14 microM IAA and 2.46 microM indolebutyric acid to induce rooting. This system of adventitious shoot production from leaf explants of adult plants could be useful for the genetic engineering and polyploidization of winter jujube.

A study of signal transduction for the two diuretic peptides of Diploptera punctata

We investigated second messengers involved in the action of the CRF-related peptide Dippu-DH46 and the calcitonin-like peptide Dippu-DH31 in Diploptera punctata. Dippu-DH46 causes a dose-dependent increase in intracellular cAMP levels, its diuretic activity is mimicked by cAMP agonists, but is attenuated by Rp-cAMPS. Dippu-DH46 acts synergistically with kinins and thapsigargin; both mobilize intracellular Ca2+. Dippu-DH46 also acts synergistically with cAMP agonists, and its effect is inhibited by a PKC inhibitor, suggesting it also activates intracellular Ca2+. Dippu-DH31 has no effect on cAMP levels and its activity is not blocked by cAMP agonists. Neither peptide stimulated cGMP levels in a dose-dependent manner, nor does cGMP have any effect on fluid secretion.

A chitosan-arginine conjugate as a novel anticoagulation biomaterial

Chitosan (CS) was modified with arginine using 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide (EDC) and N-hydroxysuccinimide (NHS) as coupling agents. FTIR and 13C NMR spectra showed that arginine was chemically coupled to CS to form a chitosan-arginine conjugate (CS-ArgC). The substitution degree of arginine in CS estimated from elemental analysis was 20.1%. The circular dichroism spectra indicated that the incorporation of arginine significantly altered the conformation of thrombin; while no obvious variation in the conformation of thrombin was observed with the addition of CS. The anticoagulation activity of glucose aldehyde crosslinked CS-ArgC and CS membranes was evaluated by assaying prothrombin time (PT), thrombin time (TT) and activated partial thromboplastin time (APTT). The APTT of CS-ArgC membrane was prolonged two times as that of CS counterpart, suggesting that the CS-ArgC is a promising candidate as an anticoagulation biomaterial.

Localization and physiological effects of RFamides in the corpora allata of the cockroach Diploptera punctata in relation to allatostatins

The distribution of FMRFamide immunoreactivity in the brain-retrocerebral complex of adult female Diploptera punctata was examined. Immunoreactivity was observed in the brain and corpus allatum as well as in the corpus cardiacum. Immunoreactivity co-localized with allatostatin immunoreactivity within several lateral neurosecretory cells of the brain and in their endings within the corpus allatum. By in vitro radiochemical assay of juvenile hormone release, the effect of two native D. punctata RFamides, an FLRFamide (Leucomyosuppressin) and an FIRFamide were examined. The latter, for which the sequence (SKPANFIRFamide) is reported here, stimulated juvenile hormone release but acted only on corpora allata from females at the end of vitellogenesis (day 6). The interaction of these two RFamides and three D. punctata allatostatins, Dippu-AST 2, 5, and 7 were similarly examined. Only Dippu-AST 2 stimulated release of RFamides from the corpora allata and only on day 6 whereas both RFamides were able to attenuate the inhibitory activity of Dippu-AST 2.

Methyl farnesoate and juvenile hormone production in embryos of Diploptera punctata in relation to innervation of corpora allata and their sensitivity to allatostatin

Corpora allata (CA) of embryos of Diploptera punctata have been previously shown to produce JH III. We have re-examined sesquiterpenoid biosynthesis throughout embryonic development and have found that early embryos produce both methyl farnesoate (MF) and JH III; as development proceeds, less MF and more JH is produced. The cockroach allatostatin peptide Dippu-allatostatin (AST) 7 inhibits sesquiterpenoid production by CA of mid to late embryos whereas it exerts a dose-dependent stimulatory effect in early embryos. This stimulatory effect is particularly apparent on MF biosynthesis. CA become innervated by allatostatin-containing nerves in early embryos (35% development). Shortly thereafter, the allatostatin-containing innervation of the CA appears complete.

Carcinogenic potential of duodenal reflux juice from patients with long-standing postgastrectomy

AIM: To determine whether study on the carcinogenic potential of reflux juice from patients with remote gastrectomy could clarify the inherent relationship between duodenal reflux and gastric stump cancer.

METHODS: A total of 37 reflux juice samples (13 Billroth I, 24 Billroth II) were employed in the present study. A two-stage transformation assay using BALB/c 3T3 cells was carried out to test the initiating or promoting activity of these samples.

RESULTS: Two of 18 (11.1%) reflux samples exerted initiating activities, whereas 9/19 (47.4%) samples enhanced the MNNG-initiating cell transformation, suggesting the duodenal reflux juice might more frequently possess the tumor-promoter activity (P = 0.029). In addition, there was no difference in initiating activities of the samples irrespective of surgical procedures (P = 0.488), while Billroth II samples exhibited stronger tumor-promoter activity than Billroth I samples (P = 0.027). Furthermore, the promoter activities were well correlated with the histological changes of the stomas (r_s = 0.625, P = 0.004), but neither their cytotoxicities nor initiating activities had this correlation (Probabilities were 0.523 and 0.085, respectively).

CONCLUSION: The duodenal reflux juice from patients with remote postgastrectomy did have carcinogenic potential, and suggested that tumor-promoting activity should principally account for the high incidence of gastric cancer in gastrectomy patients. In contrast, it is difficult to explain the high stump-cancer incidence with the "N-nitroso compounds" theory-a popular theory for the intact stomach carcinogenesis, and it seemed to be justified to focus chemoprevention of this cancer on the tumor-promoting potential of reflux juice.

Effect of isolation of periosteum and dura on the healing of rabbit calvarial inlay bone grafts

Little is understood about the role of the recipient site in the revascularization and incorporation of autogenous inlay bone grafts in the craniofacial skeleton. Clinical experience demonstrates that secondary complex cranial vault reconstruction performed with scarred avascular dura or poor soft-tissue coverage may undergo significant resorption, thus compromising the aesthetic outcome. This study was designed to determine the effect of isolating autogenous orthotopic inlay calvarial bone grafts from the surrounding dura and/or periosteum on graft revascularization, healing, and volume maintenance in the adult rabbit. Adult rabbits were randomized into four groups (n = 10 per group); in each rabbit, the authors created a circular, 15-mm in diameter, full-thickness cranial defect followed by reconstruction with an autogenous calvarial bone graft, which was replaced orthotopically and held with microplate fixation. Silicone sheeting (0.5 mm thickness) was used to isolate the dura (group II), the periosteum (group II), or both dura and periosteum (group IV) from the graft interface. No silicone was placed in group I. Animals were killed 10 weeks postoperatively, and calvaria were harvested to assess graft surface area, morphology, quantitative histology, fluorochrome staining, and revascularization. Grafts isolated from both the dura and periosteum exhibited significant decreases in total bone (cortical and trabecular) surface area, blood vessel count, and interface healing compared with nonisolated control grafts. Isolation of either the dura or periosteum significantly (p < 0.05) decreased blood vessel count but had no significant effect on interface healing. Isolation of the dura alone was associated with a significant (p < 0.05) decrease in graft cross-sectional surface area and dural cortical thickness compared with nonisolated control grafts, but this effect was not observed when the periosteum alone was isolated. Quantitative histology performed 10 weeks after surgery indicated that graft isolation was associated with increased marrow fibrosis and necrosis compared with nonisolated controls; it also demonstrated evidence of increased activity in bone remodeling (osteoblast and osteocyte count, new trabecular bone, and surface resorption). Triple fluorochrome staining suggested increased bone turnover in the nonisolated grafts compared with isolated grafts at 1 and 5 weeks postoperatively. This study demonstrates that isolating a rabbit calvarial inlay autogenous bone graft from the dura and/or periosteum results in significantly (p < 0.05) decreased revascularization, interface healing, and cross-sectional areas of amount of mature bone compared with nonisolated control grafts 10 weeks after surgery. At this time point, histologic examination demonstrates a paradoxical increase in bone remodeling in isolated bone grafts compared with controls. It is possible that the inhibition of revascularization results in a delayed onset of the remodeling phase of graft incorporation. However, in the model studied, it is not known whether the quantitative histologic and morphometric parameters measured in these isolated grafts exhibit a "catch-up" phenomenon at time points beyond 10 weeks after surgery. The results of this study emphasize the importance of a healthy recipient site in the healing and incorporation of calvarial bone grafts but stress the need for further investigation at later time points.

The polymeric immunoglobulin receptor translocates pneumococci across human nasopharyngeal epithelial cells

The polymeric immunoglobulin receptor (pIgR) plays a crucial role in mucosal immunity against microbial infection by transporting polymeric immunoglobulins (pIg) across the mucosal epithelium. We report here that the human pIgR (hpIgR) can bind to a major pneumococcal adhesin, CbpA. Expression of hpIgR in human nasopharyngeal cells and MDCK cells greatly enhanced pneumococcal adherence and invasion. The hpIgR-mediated bacterial adherence and invasion were abolished by either insertional knockout of cbpA or antibodies against either hpIgR or CbpA. In contrast, rabbit pIgR (rpIgR) did not bind to CbpA and its expression in MDCK cells did not enhance pneumococcal adherence and invasion. These results suggest that pneumococci are a novel example of a pathogen co-opting the pIg transcytosis machinery to promote translocation across a mucosal barrier.

Hospital autopsies: still valuable in their traditional role but in need of reform

In 1997, 158 autopsies were performed at Charleston Area Medical Center, a community-based, teaching tertiary care center. The autopsies revealed 29 (18.4%) clinically undiagnosed principal causes of death, of which 79% were considered treatable. The five leading undiagnosed causes were: infarctions, 27.6%; malignant neoplasms, 17.2%; pulmonary emboli, 13.8%; dissecting or ruptured aortic aneurysms, 13.8%; and genetic or congenital disorders 10.2%. These results were significantly different from those reported from some other major tertiary care centers. Reports were completed in 5-302 days (average 59, median 32 days). For more than 40 (25%) of these autopsies, the purpose was only to confirm specific disorders such as occupational injury, which can be accomplished by a highly selective, cost-effective posthumous analysis. In summary, an autopsy in today's high-technology era is still useful, however, the high cost, long length of reporting time, and number of clinically non-enlightening cases are a reasons to reform both the format and procedure in which these procedures are conducted.

Molecular and cellular mechanisms for microbial entry into the CNS

A number of pathogenic microbes including neuroinvasive viruses, bacteria and parasites are capable of entry into the central nervous system (CNS) and cause a variety of clinical manifestations. The cellular and molecular mechanisms for the CNS invasion have been extensively studied in the last two decades. Viruses invade neurons and thereby cause encephalitis or peripheral neuritis, while bacteria enter the cerebrospinal fluid (CSF) and cause meningitis. In contrast, the mechanisms for parasitic neuroinvasion are much more complex and less clear. The capabilities that enable these elite subsets of pathogens to engineer uptake into the CNS will be the subject of this review.

Effects of an allatostatin and a myosuppressin on midgut carbohydrate enzyme activity in the cockroach Diploptera punctata

Neuropeptides of the cockroach allatostatin (AST) family are known for their ability to inhibit the production of juvenile hormone by the corpora allata of cockroaches. Since their discovery, they have also been shown to modulate myotropic activity in a range of insect species as well as to act as neurotransmitters in Crustaceans and possibly in insects. The midgut of cockroaches contains numerous endocrine cells, some of which produce AST whereas others produce the FMRFamide-related peptide, leucomyosuppressin (LMS). We have determined if ASTs and LMS are also able to influence carbohydrate-metabolizing enzyme activity in the midgut of the cockroach, Diploptera punctata. Dippu-AST 7 stimulates activity of both invertase and alpha-amylase in a dose-dependent fashion in the lumen contents of ligatured midguts in vitro, but not in midgut tissue, whereas the AST analog AST(b)phi2, a cyclopropyl-ala, hydrocinnamic acid analog of Dippu-AST 6, has no effect. Leucomyosuppressin also stimulates enzyme activity in lumen contents only, although the EC50 is considerably greater than for Dippu-AST. Dippu-AST is also able to inhibit proctolin-induced contractions of midgut muscle, and this action had already been described for LMS [18]. Thus, in this organ, AST and LMS have at least two distinct physiological effects.

Pneumococcal licD2 gene is involved in phosphorylcholine metabolism

Phosphorylcholine is an important bioactive adduct to the teichoic acid (TA) and lipoteichoic acid (LTA) of the surface of Streptococcus pneumoniae. We have identified and characterized a genetic locus lic that is required for phosphorylcholine metabolism in S. pneumoniae. The pneumococcal lic locus consists of eight genes, licA, licB, licC and licD1, licD2 and three additional open reading frames. Pneumococcal licA, licB, licC, licD1 and licD2 have significant sequence similarity to licA, licB, licC and licD of Haemophilus influenzae. Mutation of licD2 led to decreased [3H]-choline uptake, aberrant migration of LTA chains in SDS-PAGE gels, loss of several surface proteins, and a phase-locked hypertransparent colony phenotype. Moreover, the licD2- mutant falled to undergo lysis after treatment with penicillin at high cell density and showed decreased transformation competence. Finally, the licD2- mutant demonstrated decreased adherence to the human type II alveolar cells, reduced nasopharyngeal colonization in infant rats, as well as significantly impaired virulence upon intraperitoneal challenge of CF1 mice. Identification of the lic genes in the pneumococcus will facilitate further characterization of the role of surface choline in microbial physiology and pathogenesis.

Studies on the determination of diacetyl guanfubase A concentration in rabbit plasma and pharmacokinetics

A gas chromatographic method for monitoring diacetyl guanfubase A in plasma is described. The procedure involved a single solvent extraction of drug from rabbit plasma into ethyl acetate with guanfubase A as an internal standard. The extract was analyzed subsequently on a gas chromatograph equipped with a hydrogen flame ionization detector. The recovery was 86.43% +/- 6.90% (+/- SD); the RSD of within-day and between-day was 2.81%-5.26% and 5.22%-8.24%, respectively; the regression line was linear over the concentration range of 25-200 micrograms/mL, the limit of detection was 10 micrograms/mL. No endogeneous interference was found in chromatograms of the biological samples. This method was applied to the pharmacokinetic study of diacetyl guanfubase A in rabbits.

Kinetics and in vivo induction of genetic variation of vlsE in Borrelia burgdorferi

The Lyme disease agent, Borrelia burgdorferi, is able to persistently infect humans and animals for months or years in the presence of an active immune response. It is not known how the organisms survive immune attack in the mammalian host. vlsE, a gene localized near one end of linear plasmid lp28-1 and encoding a surface-exposed lipoprotein in B. burgdorferi B31, was shown recently to undergo extensive genetic and antigenic variation within 28 days of initial infection in C3H/HeN mice. In this study, we examined the kinetics of vlsE sequence variation in C3H/HeN mice at 4, 7, 14, 21, and 28 days and at 7 and 12 months postinfection. Sequence changes were detected by PCR amplification and sequence analysis as early as 4 days postinfection and accumulated progressively in both C3H/HeN and CB-17 severe combined immunodeficient (SCID) mice throughout the course of infection. The sequence changes were consistent with sequential recombination of segments from multiple silent vls cassette sites into the vlsE expression site. No vlsE sequence changes were detected in organisms cultured in vitro for up to 84 days. These results indicate that vlsE recombination is induced by a factor(s) present in the mammalian host, independent of adaptive immune responses. The possible inducing conditions appear to be present in various tissue sites because isolates from multiple tissues showed similar degrees of sequence variation. The rate of accumulation of predicted amino acid changes was higher in the immunologically intact C3H/HeN mice than in SCID mice, a finding consistent with immune selection of VlsE variants.

Genetic variation of the Borrelia burgdorferi gene vlsE involves cassette-specific, segmental gene conversion

The Lyme disease spirochete Borrelia burgdorferi possesses 15 silent vls cassettes and a vls expression site (vlsE) encoding a surface-exposed lipoprotein. Segments of the silent vls cassettes have been shown to recombine with the vlsE cassette region in the mammalian host, resulting in combinatorial antigenic variation. Despite promiscuous recombination within the vlsE cassette region, the 5' and 3' coding sequences of vlsE that flank the cassette region are not subject to sequence variation during these recombination events. The segments of the silent vls cassettes recombine in the vlsE cassette region through a unidirectional process such that the sequence and organization of the silent vls loci are not affected. As a result of recombination, the previously expressed segments are replaced by incoming segments and apparently degraded. These results provide evidence for a gene conversion mechanism in VlsE antigenic variation.

Antigenic variation in Lyme disease borreliae by promiscuous recombination of VMP-like sequence cassettes

We have identified and characterized an elaborate genetic system in the Lyme disease spirochete Borrelia burgdorferi that promotes extensive antigenic variation of a surface-exposed lipoprotein, VlsE. A 28 kb linear plasmid of B. burgdorferi B31 (lp28-1) was found to contain a vmp-like sequence (vls) locus that closely resembles the variable major protein (vmp) system for antigenic variation of relapsing fever organisms. Portions of several of the 15 nonexpressed (silent) vls cassette sequences located upstream of vlsE recombined into the central vlsE cassette region during infection of C3H/HeN mice, resulting in antigenic variation of the expressed lipoprotein. This combinatorial variation could potentially produce millions of antigenic variants in the mammalian host.

Direct measurement of lipid hydroperoxides in iron-dependent spinal neuronal injury

The relationship between iron-dependent fetal mouse spinal cord neuron injury and the generation of endogenous lipid hydroperoxides (LOOHs) has been investigated. Cultured spinal cord neurons were incubated with ferrous iron (3-200 microM). Cell viability was measured in terms of the uptake of alpha-[methyl-3H]aminoisobutyric acid ([3H]AIB). Both endogenously and iron-generated LOOH, i.e., free fatty acid hydroperoxide (FFAOOH), phosphatidylethanolamine hydroperoxide (PEOOH), and phosphatidylcholine hydroperoxide (PCOOH), were measured directly by an HPLC-chemiluminescence (HPLC-CL) assay. The FFAOOH, PEOOH, and PCOOH levels in neurons incubated with 200 microM Fe2+ for 40 min were, respectively, 22-, 158-, and sevenfold higher than those in non-iron-exposed cultures, demonstrating that phosphatidylethanolamine (PE) was most sensitive to peroxidation. The dose-response and time course of Fe(2+)-induced generation of these LOOHs were also established. In both experiments, the LOOH levels were correlated directly with loss of neuronal viability, suggesting strongly a direct relationship between lipid peroxidation and cell injury. On examination of the time course of the LOOH generation, an immediate increase in PEOOH and PCOOH levels with only 30 s of Fe2+ incubation was observed. In contrast, a lag phase in the increase in FFAOOH level (2 min after Fe2+ addition) suggested a delay in the activation of phospholipase A2 (PLA2) required for the hydrolysis and generation of FFAOOH. This culture system provides an excellent model for screening antioxidant neuroprotective compounds with regard to their ability to protect against iron-dependent peroxidative injury and the relationship of the neuroprotection to inhibition of lipid peroxidation and/or PLA2.

[Neural structural relations between the chemosensitive areas of the ventrolateral medulllary surface and the medullary nuclei in rats]

Experiments were done on 30 chloralose-urethane anesthetized Sprague-Dawley strain rats. The ventrolateral medullary surface was exposed and a small millipore filter paper soaked with horseradish peroxidase (HRP) was applied locally to different parts of the underlying chemosensitive areas separately, trying to identify location of the HRP-stained cells. (1) After HRP application to the rostral area (n = 10), quite a number of labelled cells were distributed at the ventrolateral part of the nucleus of trapezoid body (Tz), the lateroventral periolivary nucleus (LVPO) and the retrotrapezoid nucleus (NRT). (2) After HRP application to the caudal area (n = 10), HRP labelled cells were mainly located at the lateral reticular nucleus (LRt) and the ventral part of at the lateral paragigantocellular nucleus LPGi. (3) After HRP application to the intermediate area (n = 6), only 8 HRP labelled cells were observed at the (LPGi) in 6 rats. (4) After HRP application to the control area (n = 4), only 6 HRP labelled cells were found at the rostral ventrolateral reticular nucleus (RVL). The above findings demonstrated the existence of the neural structural relations between the chemosensitive areas of the ventrolateral medullary surface and Tz, LVPO, NRT, LPGi, LRt, which supports that all these nuclei might participate in the central chemoreception of respiration.

[Role of the lateroventral periolivary nucleus in the central chemoreception of respiration in rats]

Using the methods of microinjection, microiontophoresis, electrolytic destruction and electric stimulation, the present work was undertaken to investigate whether the lateroventral periolivary nucleus (LVPO) might play a role in the central mechanism of chemoreception on respiration. Experiments were performed on 38 chloralose-urethane anesthetized Sprague-Dawley rats. The results were as follows: (1) Bilateral microinjection of acidified mock CSF into the LVPO region, evoked an enhancement in respiratory activities. (2) Microiontophoretic application of H+ caused mainly excitatory effects on the spontaneously discharging units in LVPO region, and some of the excitatory units were also responsible to microinjection of acidified mock CSF to the ventrolateral medullary surface. (3) After the electrolytic destruction of bilateral LVPO region in carotid body denervated rats, respiratory response to inhaled CO2 was attenuated significantly. (4) Electric stimulation of LVPO region caused an increase in discharging frequency of some units in the NTS and NRA regions. The above results indicate that LVPO plays a significant role in the central mechanism of chemoreception.

HPLC-chemiluminescence and thermospray LC/MS study of hydroperoxides generated from phosphatidylcholine

Lipid hydroperoxides generated from phosphatidylcholine (PC) by two commonly employed phosphatidylcholine hydroperoxide (PCOOH) generation methods were examined by HPLC-chemiluminescence (CL) and thermospray LC/MS assay. This HPLC-CL assay is specific for hydroperoxides. In the HPLC-CL chromatograms, a major peak eluted at 4.7 min for the samples generated by the photooxidation of PC in the presence of methylene blue. The direct LC/MS analysis of the hydroperoxides contained in this peak determined that the hydroperoxides are mono- and di-PCOOH. Quantitation showed that over 90% of the hydroperoxides generated by photooxidation are PCOOH. In contrast, a different major peak appeared at 3.7 min for the hydroperoxides generated by the incubation of PC with the azo compound AMVN. We determined by LC/MS analysis that the hydroperoxides contained in this peak were not equivalent to either mono- or di-PCOOH. Indeed, 70%-95% of the hydroperoxides generated by AMVN incubation were not PCOOH, but rather a large portion were AMVN-derived hydroperoxides. The hydroperoxides contained in the 4.7-min peak (i.e., PCOOH) were preferentially responsive to cytochrome c-luminol CL cocktail (about 100-fold more responsive than the hydroperoxides in the 3.7-min peak), whereas the hydroperoxides in the 3.7-min peak (including AMVN-derived hydroperoxide) were preferentially responsive to microperoxidase-isoluminol CL cocktail (about 20-fold more responsive than the PCOOH), suggesting a substrate specificity for the CL cocktail.

Effects of alloxan on electric activity of mouse pancreatic B cells in vitro

Microelectrode method for recording membrane potentials was used. It was observed that alloxan possessed stimulative and toxic dual effects on the electric activity of pancreatic B cells. A 10-min exposure to alloxan 14 mmol.L-1 in the perfusion medium without glucose caused a significant depolarization of B cells from -44 +/- 13 mV to -36 +/- 12 mV (n = 7, P < 0.05) and evoked spikes in B cells. But the spikes disappeared at 24 +/- 12 min (n = 8). In the presence of glucose 5.5 mmol.L-1 or 11.0 mmol.L-1, the dual effects became weaker or not obvious. After 10-min exposure to diazoxide (an ATP sensitive K+ channel opener) 0.8 mmol.L-1 in the perfusion medium with alloxan 14 mmol.L-1 but devoid of glucose, the amplitude of membrane potential went up from -31 +/- 11 mV to -48 +/- 21 mV and the mean value of spikes dropped from 31 +/- 24 spikes.min-1 to 5 +/- 5 spikes.min-1. It was suggested that the stimulative effect of alloxan was due to blocking of ATP sensitive K+ channel and a higher concentration of glucose could prevent B cells from alloxan injury.

Direct measurement of hydroxyl radicals, lipid peroxidation, and blood-brain barrier disruption following unilateral cortical impact head injury in the rat

We present data correlating the time courses of hydroxyl radical (.OH) production, lipid peroxidation, and blood-brain barrier (BBB) damage following unilateral head injury in the rat. Using a controlled cortical impact device to inflict head injury, we have directly measured brain .OH levels via the salicylate trapping method, and phosphatidylcholine hydroperoxide (PCOOH) levels via the HPLC-chemiluminescence technique, at 5, 30, and 60 min postinjury. These results were then correlated with the time course of BBB disruption, as measured by the extravasation of Evans blue dye (EB) into the injured cortex, over the same time period. In the present study, .OH levels were 62% higher than sham at 5 min postinjury, 25% higher at 15 min (both p < or = 0.05), and no different from sham at 60 min. PCOOH, on the other hand, increased linearly between 5 and 60 min postinjury. Whereas PCOOH levels were 25% greater than sham at 5 min, they were 35% and 52% higher than sham at 30 and 60 min, respectively (both p < or = 0.05 vs sham). Blood-brain barrier disruption followed a similar time course to PCOOH generation, except that the magnitude of the effect was much greater. Whereas EB extravasation was only slightly elevated in the injured cortex at 5 min postinjury, there was nearly an 8-fold increase at 30 min and an 11-fold increase at 60 min (all p < or = 0.05 vs sham). An additional experiment demonstrated that BBB damage can be attenuated by treatment with the 21-aminosteroid lipid peroxidation inhibitor, tirilazad mesylate (U-74006F). Rats were given a single i.v. injection of 3 or 10 mg/kg of U-74006F 5 min postinjury and killed 30 min postinjury. The 10 mg/kg dose of U-74006F reduced EB extravasation 52% (p < 0.025) in comparison to vehicle-treated controls. This is the first study to correlate the time courses of .OH formation, lipid peroxidation, and BBB disruption in injured brain. The results suggest that there is an immediate, posttraumatic burst in .OH formation, followed by a progressive increase in lipid peroxidation and a similar, although slightly delayed, time-related opening of the BBB. The attenuation of BBB damage by U-74006F suggests that this chain of events can be interrupted by administration of an antioxidant/lipid peroxidation inhibitor.

[Analysis of the acetylcholine action on the electrical activities of pancreatic islet B-cells in mice]

Intracellular potential recording and extracellular microiontophoretic techniques were used to study the acetylcholine (ACh) action on the electrical activities of pancreatic islet B-cells in mice. The B cell membrane potential was decreased (5-10 mV) and the spikes were increased (11-17/30 s) by the ACh microinotophoresis. These effects were dependent on glucose and completely blocked by atropine. However, pirenzepine could attenuate the electrical activity by approximately 70%. The ACh-induced membrane depolarization was Ca(2+)-independent and blocked by TTX. But the effect of ACh on spikes was Ca(2+)-dependent and not blocked by verapamil. The results showed that ACh action in the enhancement of glucose-dependent electrical activities of B-cell were mediated by muscarinic receptor, mainly by subtype M1. Then TTX-sensitive Na channel and verapamil-insensitive Ca channel were activated by M1 receptors. Na+ influx resulted in membrane depolarization and Ca2+ influx enhanced spike discharges.

Age-related phospholipid hydroperoxide levels in gerbil brain measured by HPLC-chemiluminescence and their relation to hydroxyl radical stress

Phosphatidylcholine hydroperoxide (PCOOH) was directly quantified in the hippocampus, cortex and striatum from young (3 months), middle-aged (15 months) and old (20 to 24 months) gerbils by an HPLC-chemiluminescence assay. PCOOH levels in hippocampus and cortex were found between 8.05 to 8.58 pmol/mg tissue and no statistically significant difference was found across the age groups. In striatum, however, PCOOH levels were significantly higher in middle-aged and old gerbils compared to those in young animals. The regional comparison showed that PCOOH levels were significantly higher in striatum than in cortex or hippocampus for all the age groups. Moreover, this regional difference increased with aging, from approximately 20% in young animals to 30% and 40% in middle-aged and old gerbil striatum. PCOOH to phospholipid ratio is approximately the same for all age groups at the level of 1.5/10,000, although it is slightly lower in the cortex. The hydroxyl radical levels in the brain were also measured by the formation of its salicylate trapped product 2,3-DHBA and used as a measure of oxidative stress. The PCOOH levels was used as a measure of oxygen radical-induced lipid peroxidative damage. PCOOH as a function of hydroxyl radical stress was calculated and expressed as PCOOH/2,3-DHBA, representing the oxidative damage as a function of the level of oxidative stress. It also implies the tissue susceptibility to oxidative stress and the efficiency of the antioxidant systems. In hippocampus and cortex, the ratios are high in young gerbils, decrease at middle-age and significantly increase in the old.(ABSTRACT TRUNCATED AT 250 WORDS)

High in vitro endotoxin responsiveness of macrophages from an endotoxin-resistant wild rodent species, Sigmodon hispidus

It has been reported that macrophages primarily mediate endotoxin shock and cell death by synthesizing and releasing cytokines, largely tumor necrosis factor (TNF) and interleukin-1 (IL-1). However, macrophages from some laboratory mouse strains such as C3h/HeN are unresponsive to endotoxin both in vivo and in vitro. We found members of a wild rodent species, Sigmodon hispidus, to also be extremely resistant to bacterial endotoxin challenge. Intravenous administration of up to 100,000 micrograms/kg body mass of Escherichia coli O26:B6 endotoxin did not cause lethality in adult S. hispidus. In contrast to the endotoxin-resistant mouse strain, peritoneal macrophages derived from S. hispidus were responsive to in vitro endotoxin challenge as measured by high levels of TNF and IL-1 activity in supernatants of macrophage cultures. Thus, in vitro macrophage responsiveness to endotoxin does not always indicate high host sensitivity to endotoxin challenge.

Age-related regional changes in hydroxyl radical stress and antioxidants in gerbil brain

The levels of hydroxyl radicals and oxidized GSH have been examined as indices of oxidative stress in young (3 months), middle-aged (15 months), and old (20-24 months) gerbil brain hippocampus, cortex, and striatum. The hydroxyl radical stress was estimated by measuring the salicylate hydroxyl radical trapping products 2,5- and 2,3-dihydroxybenzoic acid. The stress was significantly higher in all three brain regions in middle-aged and old gerbils versus young animals (< or = 66.0%). Regional comparisons showed that the stress was significantly higher in cortex than in either the hippocampus or striatum of the middle-aged and old gerbils (< or = 32.0%). The ratio of oxidized to total GSH also increased progressively in middle-aged and old animals in all three brain regions (p < 0.05, < or = 41.1%), further indicating a general age-related increase in oxidative stress. Parallel to this age-related increase in oxidative stress, a significant, albeit slight (8%), decrease in neuronal number in hippocampal CA1 region was observed in both the middle-aged and old animals. Possible differences in antioxidant levels were also examined. Total GSH levels were similar across age groups (variance < 12%). However, the regional comparison showed that it was highest in striatum in all age groups. The levels of alpha-tocopherol (vitamin E) were significantly higher in the middle-aged and old animals in all three regions (< or = 70.4%). Vitamin E was highest in the hippocampus and the differences between the hippocampus and the cortex and striatum increased with age.(ABSTRACT TRUNCATED AT 250 WORDS)

[Inhibitory effect of diazepam or flurazepam on pressor response induced by the stimulation of midbrain in the rabbit]

Experiments were performed on 32 rabbits anaesthetized with alpha-chloralose and urethane, paralyzed with flaxidil and artificially ventilated. The pressor response was elicited by stimulation of dorsal part of midbrain periaqueductal gray (dPAG). Intravenous injection of diazepam (2 mg/kg) or intracerebroventricular application of flurazepam (2 mg/50 microliters) resulted in attenuation of the pressor response induced by the stimulation of midbrain. Bilateral microinjection of flurazepam (100 micrograms in 0.25 microliter) into rostral ventrolateral medulla (rVLM) depressed the pressor response to midbrain stimulation. Microinjection of flurazepam of the same dosage into caudal ventrolateral medulla (cVLM), however, had no depressant effect. Pretreatment with bicuculline in rVLM prevented the inhibitory effect of flurazepam on the pressor response. These results mentioned above suggest that diazepam or flurazepam inhibits the pressor response evoked by midbrain stimulation, and the effect may be mediated by the activation of the GABAA receptor in rVLM.

The genotoxic effects of arachidonic acid in V79 cells are mediated by peroxidation products

Chinese hamster lung fibroblasts (V79 cells) were exposed to 2, 20, 160, and 200 microM arachidonic acid (AA). At 20 microM, a stimulatory effect on cell growth was observed, while at 200 microM, an inhibitory effect was found. AA at 160 and 200 microM induced a 10- to 12-fold increase of 6-thioguanine-resistant mutants in V79 cells, whereas increased alkaline labile sites on DNA were consistently produced only with 200 microM treatment doses. The induction of alkaline labile lesions was partially inhibited in the presence of an antioxidant NDGA. [3H]AA metabolism in cells was examined by HPLC analysis following reductive transmethylation of the cell lipid extracts. Two fractions corresponding to [3H]AA-derived peroxidation products were identified by HPLC-radiochromatography and analyzed by mass spectrometry. Quantitative evaluation of the radioactivity associated with these peaks revealed an increase in [3H]AA peroxidation products when cells were exposed to increasing amounts of AA. The AA-dependent stimulation of lipid peroxidation product formation was partially inhibited when cells were treated in the presence of NDGA. The results provide evidence that substantially enlarged AA pools in cells may induce genotoxic effects mediated through increased endogenous lipid peroxidation products.

Effect of vitamin E on arachidonic acid peroxidation and its binding to Chinese hamster V79 cell DNA

Following 24 h incubation in standard culture medium (containing 2 microM of arachidonic acid, AA), and 10 and 20 microM supplemented AA, approx. 55, 40 and 33%, respectively, of the fatty acid was incorporated into Chinese hamster V79 cell lipids. The AA content of cells increased 5 to 7-fold with the 10 and 20 microM supplementations of AA and, there was a correspondingly marked decrease in the proportion of AA incorporated into phospholipids (94 vs. 50 and 32%), whereas an increased percentage of AA was recovered in triacylglycerols (1 vs. 30 and 50%) and free fatty acids (1 vs. 3 and 8%). AA at 12 and 22 microM induced a 50 and 80% increase, respectively, in cellular content of thiobarbituric acid reactive substances (TBARS), an indication of increased peroxidation of cell lipids. This formation of TBARS was inhibited by vitamin E but not by indomethacin or SKF-525. Binding of [3H]AA-derived counts to DNA increased in parallel to the levels of cellular lipid peroxidation. Vitamin E added to the culture medium at 10(-4) M was readily taken up by the cells within 48 h and significantly reduced both lipid peroxidation and binding of AA-derived counts to DNA, without affecting AA uptake. Cell vitamin E content was significantly reduced following 24 h incubation in the presence of 10 and 20 microM supplemented AA. This study indicates that products of lipid peroxidation can bind to DNA in cultured cells, and points to a potential cyto- and geno-toxic risk posed by increased cellular AA content relative to anti-oxidant defenses.