Metal nano-grid reflective wave plate

We propose an optical wave plate using a metal nano-grid. The wave plate operates in reflection mode. A single-mode truncated modematching theory is presented as a general method to design such nano-grid wave plates with the desired phase difference between the reflected TM and TE polarizations. This analytical theory allows angled incidence calculations as well, and numerical results agree-well with comprehensive finite-difference time-domain electromagnetic simulations. Due to the subwavelength path-length, the reflective wave plate is expected to have improved broad-band functionality over existing zero-order transmissive wave plates, for which an example is provided. The proposed wave plate is simple and compact, and it is amenable to existing nanofabrication techniques. The reflective geometry is especially promising for applications including liquid-crystal displays and laser feedback experiments.

Combination of short CAG and GGN repeats in the androgen receptor gene is associated with acne risk in North East China

BACKGROUND

Acne vulgaris is one of the most common skin disorders, and androgen is known to play a key role in the development of acne. However, the exact genetic mechanism by which androgen receptor (AR) gene affects acne development is still unclear.

OBJECTIVE

Our study aimed to investigate whether CAG and GGN polymorphism of the AR gene are associated with acne risk.

PATIENTS AND METHODS

Two hundred thirty-eight patients and 207 controls were included in the study. The repeat lengths of the AR gene were determined by GeneScan analysis.

RESULTS

Men with CAG < 23 and women with CAG < 24 had significant risk compared to those men with CAG > or = 23 [odds ratio (OR), 2.07; 95% confidence interval (95% CI), 1.21-3.54] and women with CAG > or = 24 (OR, 2.05; 95% CI, 1.18-3.56). In males, GGN repeats, considered independently of the CAG repeat, have no significant effect on the acne risk; however, when combined with CAG repeats, the acne patients exhibited significantly higher frequency of the haplotypes CAG < 23/GGN < or = 23 (OR, 3.33; 95% CI, 1.10-10.07; P < 0.05) compared with the controls.

CONCLUSION

Our results of this study strongly indicated that a shorter CAG repeat length and specific haplotypes of AR attributed to the risk of acne development and thus could serve as a susceptibility marker.

Abrogation of mitochondrial transcription in smooth muscle cells impairs smooth muscle contractility and vascular tone

BACKGROUND

Smooth muscle cells (SMC) constitute the major contractile cell population of blood vessels and inner organs. SMC contraction depends on energy provided by adenosine triphosphate (ATP) catabolism, which can be generated through oxidative phosphorylation in mitochondria or by anaerobic glycolysis. Mitochondrial activity may also modulate smooth muscle tone by biotransformation of vasoactive mediators. Here, we study the role of mitochondrial DNA gene expression for vascular function in vivo.

METHODS

Since loss of functional mitochondria in SMC may not be compatible with normal development, we generated mice with inducible SMC-specific abrogation of the mitochondrial transcription factor A (Tfam). Deletion of this gene leads to dysfunctional mitochondria and prevents aerobic ATP production in affected cells.

RESULTS

Invasive blood pressure monitoring in live animals demonstrated that SMC specific Tfam deletion results in lower blood pressure and a defective blood-pressure response to stress, changes that were not compensated by increased heart rate. The contractility to agonists was reduced in arterial and gastric fundus strips from Tfam-deficient mice. Endothelium-dependent relaxation of arterial strips in response to ACh was also blunted.

CONCLUSION

Our data show that mitochondrial function is needed for normal gastric contraction, vascular tone, and maintenance of normal blood pressure.

Expression of membrane progesterone receptors on human T lymphocytes and Jurkat cells and activation of G-proteins by progesterone

Although there is significant evidence for progesterone's role as an immunomodulator, nuclear progesterone receptors have not been consistently identified in immune cells. Recently, three new putative membrane progesterone receptors (mPRs), mPRalpha, mPRbeta, and mPRgamma have been described. The objective of this study was to examine whether mPRs are expressed in peripheral blood leukocytes (PBLs) in women of reproductive age, and to further characterize them in T lymphocytes and immortalized T cells (Jurkat cells). Transcripts for mPRalpha and mPRbeta but not mPRgamma, were detected by RT-PCR in PBLs, T lymphocytes, and Jurkat cells. Western blot analysis showed the presence of the mPRalpha and mPRbeta proteins on cell membranes of T lymphocytes and Jurkat cells. Expression of the mPRalpha mRNA was upregulated in the luteal phase of the menstrual cycle in cluster of differentiation (CD)8+, but not in CD4+, T lymphocytes. Radioreceptor assays revealed specific [(3)H]progesterone binding to T- and Jurkat cell membranes (K(d) 4.25 nM) characteristic of steroid membrane receptors. Progesterone activated an inhibitory G-protein (G(i)), suggesting that mPRs are coupled to G(i) in Jurkat cells. These results suggest a potential novel mechanism for progesterone's immunoregulatory function through activation of mPRs.

Activation of the novel estrogen receptor G protein-coupled receptor 30 (GPR30) at the plasma membrane

G protein-coupled receptor 30 (GPR30), a seven-transmembrane receptor (7TMR), is associated with rapid estrogen-dependent, G protein signaling and specific estrogen binding. At present, the subcellular site of GPR30 action is unclear. Previous studies using antibodies and fluorochrome-labeled estradiol (E2) have failed to detect GPR30 on the cell surface, suggesting that GPR30 may function uniquely among 7TMRs as an intracellular receptor. Here, we show that detectable expression of GPR30 on the surface of transfected HEK-293 cells can be selected by fluorescence-activated cell sorting. Expression of GPR30 on the cell surface was confirmed by confocal microscopy using the lectin concanavalin A as a plasma membrane marker. Stimulation of GPR30-expressing HEK-293 cells with 17beta-E2 caused sequestration of GPR30 from the cell surface and resulted in its codistribution with clathrin and mobilization of intracellular calcium stores. Evidence that GPR30 signals from the cell surface was obtained from experiments demonstrating that the cell-impermeable E2-protein conjugates E2-BSA and E2-horseradish peroxidase promote GPR30-dependent elevation of intracellular cAMP concentrations. Subcellular fractionation studies further support the plasma membrane as a site of GPR30 action with specific [3H]17beta-E2 binding and G protein activation associated with plasma membrane but not microsomal, or other fractions, prepared from HEK-293 or SKBR3 breast cancer cells. These results suggest that GPR30, like other 7TMRs, functions as a plasma membrane receptor.

Effects of Dietary Copper Supplementation and Copper Source on Digesta pH, Calcium, Zinc, and Copper Complex Size in the Gastrointestinal Tract of the Broiler Chicken

An experiment was conducted to study the effects of high dietary Cu and Cu source on the pH of digesta from the gizzard, duodenum + jejunum, ileum, and complex size of Ca, Zn, and Cu in the duodenum + jejunum digesta of broiler chickens. Ross 308 male broiler chicks were randomly assigned to 32 cages and fed 1 of 4 treatments: control, 250 ppm Cu from sulfate, 250 ppm Cu from lysinate, and 250 ppm tribasic Cu from chloride from 15 to 21 d of age. Copper supplementation and Cu source had no effects on pH of gizzard or duodenum + jejunum contents. Copper supplementation, however, increased the pH of the ileal contents (P < 0.05) but was not affected by Cu source. Neither Cu supplementation nor Cu source had significant effects on the solubility of Ca in the duodenum + jejunum contents, and the portions of Ca existing in different soluble complex sizes: >100,000, 100,000 to 30,000, 30,000 to 5,000, and <5,000 molecular weight (MW) in the duodenum + jejunum digesta. About 80% of soluble Ca, Cu, and Zn was associated with either large complexes (>100,000 MW) or small complexes (<5,000 MW). The solubility of supplemental Cu in digesta was from 59 to 61% (P < 0.05), but solubility was not affected by Cu source. No effects on portions of Cu existing in different sizes of complexes in the supernatant were noted. Copper lysinate decreased the Zn solubility in the digesta (P < 0.05), but Cu sulfate and tribasic Cu chloride supplementation did not. Copper supplementation increased (P < 0.05) the percentage of Zn associated with large complexes (>100,000 MW) and decreased (P < 0.05) the percentage of Zn associated with small complexes (<5,000 MW; P < 0.05), thereby suggesting an antagonism between Cu and Zn.

Role of Gab2 in mammary tumorigenesis and metastasis

Overexpression of the adaptor/scaffolding protein Gab2 has been detected in primary human breast cancer cells and cell lines, although its functional significance in breast carcinogenesis is not fully understood. Here, we show a requirement for Gab2 in promoting mammary tumor metastasis. Although Gab2 expression levels were elevated in mammary tumors induced by the Neu (ErbB-2) oncogene, homozygous deletion of Gab2 in mice had only a modest effect on the initiation of Neu-induced mammary tumors. Notably, ablation of Gab2 severely suppressed lung metastasis. Gab2-deficient cancer cells displayed normal Akt activities, and their proliferative rate in vitro was similar to control cells. However, Gab2(-/-) cancer cells exhibited decreased migration and impaired Erk activation, and the defects were rescued by re-introduction of Gab2 into Gab2(-/-) cells. These findings suggest that although Gab2 overexpression may confer growth advantage to tumor cells, the functional requirement for Gab2 in mammary tumor initiation/growth may be dispensable, and that Gab2 may have a prominent role in promoting mammary tumor metastasis.

An auditory vigilance task for mental fatigue detection

An Auditory Vigilance Task (AVT) as a validation criterion for monitoring mental fatigue was proposed in this study. The biological basis of this task design is on the understanding that mental fatigue is a cortical deactivation. This AVT is simple to perform, free of learning curve and independent on acquired skills (aptitude, knowledge). The validity and sensitivity of this task was verified by a scientifically controlled 25-hour fatigue experiment recorded by Electroencephalogram (EEG). Results showed that this AVT is highly sensitive to changes during fatigue process. The effectiveness of this AVT was compared to one subjective rating scale (FSS). The 5-level fatigue EEG datasets (labeled by AVT and FSS respectively) were fed into Support Vector Machines (SVM). SVM test accuracy indicated that AVT is more effective than subject's own estimation. The results demonstrate conclusively that this AVT is suitable for fatigue detection study as a reliable validation criterion.

Steroid and G protein binding characteristics of the seatrout and human progestin membrane receptor alpha subtypes and their evolutionary origins

A novel progestin receptor (mPR) with seven-transmembrane domains was recently discovered in spotted seatrout and homologous genes were identified in other vertebrates. We show that cDNAs for the mPR alpha subtypes from spotted seatrout (st-mPRalpha) and humans (hu-mPRalpha) encode progestin receptors that display many functional characteristics of G protein-coupled receptors. Flow cytometry and immunocytochemical staining of whole MDA-MB-231 cells stably transfected with the mPRalphas using antibodies directed against their N-terminal regions show the receptors are localized on the plasma membrane and suggest the N-terminal domain is extracellular. Both recombinant st-mPRalpha and hu-mPRalpha display high affinity (Kd 4.2-7.8 nm), limited capacity (Bmax 0.03-0.32 nm), and displaceable membrane binding specific for progestins. Progestins activate a pertussis toxin-sensitive inhibitory G protein (G(i)) to down-regulate membrane-bound adenylyl cyclase activity in both st-mPRalpha- and hu-mPRalpha-transfected cells. Coimmunoprecipitation experiments demonstrate the receptors are directly coupled to the G(i) protein. Similar to G protein-coupled receptors, dissociation of the receptor/G protein complex results in a decrease in ligand binding to the mPRalphas and mutation of the C-terminal, and third intracellular loop of st-mPRalpha causes loss of ligand-dependent G protein activation. Phylogenetic analysis indicates the mPRs are members of a progesterone and adipoQ receptor (PAQR) subfamily that is only present in chordates, whereas other PAQRs also occur in invertebrates and plants. Progesterone and adipoQ receptors are related to the hemolysin3 family and have origins in the Eubacteria. Thus, mPRs arose from Eubacteria independently from members of the GPCR superfamily, which arose from Archeabacteria, suggesting convergent evolution of seven-transmembrane hormone receptors coupled to G proteins.

[Molecular cloning and characterization of a novel WRKY gene from Brassica chinensis]

A new WRKY gene was cloned from Brassica chinensis by rapid amplification of cDNA ends (RACE). The full-length cDNA of BcWRKY was 1175 bp long and contained a 924 bp open reading frame (ORF) encoding a putative W-box-binding protein of 308 amino acids. The predicted BcWRKY protein was found to have a potential bipartite nuclear localization sequence (NLS-BP) in its N-terminal region followed by a WRKY DNA-binding domain. Bioinformatic analysis revealed that BcWRKY resembled other WRKY domain-containing proteins from Arabidopsis (AtWRKY18), tobacco (WIZZ), parsley (PcWRKY4) and wild oat (ABF2). Expression of the BcWRKY gene could be induced by salicylic acid (SA), and influenced by Pseudomonas syringae pv. tomato strain DC3000 infection and wounding treatment. Our study implies that BcWRKY might have similar functions possessed by other WRKY genes such as inducing the expression of some defense-related genes and increasing plant's disease resistance ability.

Role of interleukin-6 in lipopolysaccharide-induced brain injury and behavioral dysfunction in neonatal rats

There are increasing data in support of the hypothesis that inflammatory cytokines are involved in neonatal white matter damage. Despite extensive study of the proinflammatory cytokines tumor necrosis factor-alpha and interleukin-1beta, the role of interleukin-6 in the development of white matter damage is largely unknown. In the present study, the role(s) of interleukin-6 in mediating lipopolysaccharide-induced brain injury and behavioral changes was investigated by the intracerebral injection of lipopolysaccharide with interleukin-6 neutralizing antibody in the 5-day-old rat brain. Brain injury was examined in brain sections at postnatal day 8 and postnatal day 21. Behavioral tests including righting reflex, wire hanging maneuver, cliff avoidance, locomotor activity, gait analysis, responses in the elevated plus-maze and passive avoidance were performed from postnatal day 3 to postnatal day 21. Changes in astroglia, microglia and oligodendrocytes were studied using immunohistochemistry in the postnatal day 21 rat brain. Our results show that interleukin-6 antibody attenuated lipopolysaccharide-induced brain lateral ventricle dilation and improved neurobehavioral performance. Interleukin-6 antibody also suppressed lipopolysaccharide-induced astrogliosis and microglial activation, and increased the number of oligodendrocytes in white matter. However, no changes of tumor necrosis factor-alpha and interleukin-1beta were detected. In contrast, no histopathological changes and glial activation were observed in rats injected with only interleukin-6. The present study indicates that the contribution to brain injury by interleukin-6 depends on its interaction with other lipopolysaccharide-induced agents and not on interleukin-6 alone.

Minocycline alleviates hypoxic-ischemic injury to developing oligodendrocytes in the neonatal rat brain

The role of minocycline in preventing white matter injury, in particular the injury to developing oligodendrocytes was examined in a neonatal rat model of hypoxia-ischemia. Hypoxia-ischemia was achieved through bilateral carotid artery occlusion followed by exposure to hypoxia (8% oxygen) for 15 min in postnatal day 4 Sprague-Dawley rats. A sham operation was performed in control rats. Minocycline (45 mg/kg) or normal phosphate-buffered saline was administered intraperitoneally 12 h before and immediately after bilateral carotid artery occlusion+hypoxia and then every 24 h for 3 days. Nissl staining revealed pyknotic cells in the white matter area of the rat brain 1 and 5 days after hypoxia-ischemia. Hypoxia-ischemia insult also resulted in apoptotic oligodendrocyte cell death, loss of O4+ and O1+ oligodendrocyte immunoreactivity, and hypomyelination as indicated by decreased myelin basic protein immunostaining and by loss of mature oligodendrocytes in the rat brain. Minocycline significantly attenuated hypoxia-ischemia-induced brain injury. The protective effect of minocycline was associated with suppression of hypoxia-ischemia-induced microglial activation as indicated by the decreased number of activated microglia, which were also interleukin-1beta and inducible nitric oxide synthase expressing cells. The protective effect of minocycline was also linked with reduction in hypoxia-ischemia-induced oxidative and nitrosative stress as indicated by 4-hydroxynonenal and nitrotyrosine positive oligodendrocytes, respectively. The reduction in hypoxia-ischemia-induced oxidative stress was also evidenced by the decreases in the content of 8-isoprostane in the minocycline-treated hypoxia-ischemia rat brain as compared with that in the vehicle-treated hypoxia-ischemia rat brain. The overall results suggest that reduction in microglial activation may protect developing oligodendrocytes in the neonatal brain from hypoxia-ischemia injury.

Steinernema akhursti sp. n. (Nematoda: Steinernematidae) from Yunnan, China

A new species of entomopathogenic nematode, herein described as Steinernema akhursti sp. n., was recovered from soil samples collected from Yunnan Province, the People's Republic of China. Both morphological and molecular data show congruently that S. akhursti sp. n. belongs to the Steinernema feltiae group. It can be separated from all described Steinernema species by the combined morphological and morphometrical characters of various stages of the nematodes. For the first generation male, the new species can be recognized by spicule length 90 +/- 4.6 microm, spicule tip blunt with an aperture on the ventral side, gubernaculum with a long and needle-shaped cuneus, and tail conoid with a prominent mucron on the tip and a concave on ventral side. For the infective juvenile, the combination of the following characters: body length 812 +/- 19 microm, distance from anterior end to excretory pore 59 +/- 1.5 microm, tail length 73 +/- 2.9 microm, E% 77 +/- 4.5, lateral field with six evenly distributed and identical ridges at the middle body portion, and tail with long and slightly constrict hyaline portion can be used to separate the new species from other nematodes. For the female, the new species is characterized by: tail conoid with a short mucron and slightly swelling anal portion and a symmetrical, slightly protruding vulva with conspicuous double-flapped epiptygma. The nematode can be separated from other described species of Steinernema by DNA sequences of either a partial 28S rDNA or the internal transcribed spacer regions of rDNA and from the closely related species S. feltiae and Steinernema oregonense by cross-breeding tests.

Efficient expression of vip184DeltaP gene under the control of promoters plus Shine-Dalgarno (SD) sequences of cry genes from Bacillus thuringiensis

AIMS

To compare vip184DeltaP gene expression time course and Vip184 protein yield under the control of promoters and Shine-Dalgarno (SD) sequences of vip184, cry3A and cry1A gene from Bacillus thuringiensis respectively.

METHODS AND RESULTS

Derived from the shuttle vector pHT3101, recombinant plasmids pHPT3, pHTP3A(Delta)P and pHTP1A(Delta)P were constructed with the native vip184 gene and the vip184(Delta)P gene, either under the control of promoters and SD sequences of cry3A or cry1A genes. When the above plasmids were transformed into an acrystalliferous B. thuringiensis strain Cry(-)B, their expression time course were consistent with those of vip184, cry3A and cry1A gene respectively. The maximum yields of Vip184 protein were increased when under the control of promoters plus SD sequences of cry3A and cry1A gene.

CONCLUSIONS

The results showed that both cry3A and cry1A promoter/SD sequence combinations were able to enhance synthesis of Vip184 and change its expression time course.

SIGNIFICANCE AND IMPACT OF THE STUDY

Both cry3A and cry1A promoter/SD systems offer a method for improving the expression efficacy of the vip184 gene in B. thuringiensis and it is possible to co-express the vip184 gene and cry genes and accumulate Vip184 in the form of inclusion bodies by these systems in order to construct novel useful B. thuringiensis engineered strains.

MRI and 2D-CSI MR spectroscopy of the brain in the evaluation of patients with acute onset of neuropsychiatric systemic lupus erythematosus

MRI and 2D-CSI spectroscopy were performed in eight patients with systemic lupus erythematosus who presented with acute onset of neuropsychiatric lupus (NP-SLE), and in seven normal controls to evaluate for differences in metabolic peaks and metabolic ratios between the two groups. Also, the interval change of the metabolic peaks and their ratios during treatment in the NP-SLE patient group was evaluated. Metabolic peaks for N-acetyl-aspartate (NAA), choline (Cho), creatine (Cr), and lactate/lipids (LL) and their ratios (NAA/Cr, NAA/Cho, Cho/Cr, LL/Cr) were determined at initial presentation and 3 and 6 months later. In the eight lupus patients compared to the seven normal controls, NAA/Cho ratios were lower at presentation (1.05 vs 1.25; p = 0.004) and decreased even further at the three month follow-up (0.92 vs 1.05; p = 0.008). In contrast, both Cho/Cr (1.42 vs 1.26; p = 0.026) and LL/Cr ratios (0.26 vs 0.19; p = 0.002) were higher in the lupus patients at presentation compared to the controls and did not significantly change at three and six months follow-up. The NAA/Cr ratios were lower in the lupus patients compared to the controls at presentation but the difference was not statistically significant. However, the mean NAA/Cr significantly decreased from the initial examination to the three month follow-up (1.42 vs 1.32; p = 0.049) but did not significantly change from the three to the six month follow-up examinations. The NAA/Cr, Cho/Cr, and NAA/Cho ratios varied significantly (p < 0.05, p < 0.05, p < 0.05, respectively) between the 17 different locations measured in the brain in all eight patients and seven controls. Both the NAA/Cr ratios and the Cho/Cr ratios were also significantly lower in the gray matter than in the white matter (p < 0.0001) in both patients and controls, whereas the LL/Cr and NAA/Cho ratios were not significantly different. In conclusion, 2D-CSI MR spectroscopy may be useful in the early detection of metabolic CNS changes in NP-SLE patients with acute onset of new neurological symptoms as well as in the follow-up after treatment to assess presence and changes in metabolic brain injury. However, although there are detectable differences between normal individuals and lupus patients it is currently unclear whether these relate to the acute episode. Future studies are needed comparing NP-SLE patients with active CNS involvement with those inactive disease.

Minocycline attenuates lipopolysaccharide-induced white matter injury in the neonatal rat brain

Our previous studies have shown that intracerebral administration of endotoxin, lipopolysaccharide (LPS), induces selective white matter injury and hypomyelination in the neonatal rat brain and that the LPS-induced brain injury is associated with activation of microglia. To test the hypothesis that inhibition of microglial activation may protect against LPS-induced white matter injury, we examined roles of minocycline, a putative suppressor of microglial activation, on LPS-induced brain injury in the neonatal rat. A stereotactic intracerebral injection of LPS (1 mg/kg) was performed in postnatal day 5 Sprague-Dawley rats and control rats were injected with sterile saline. Minocycline (45 mg/kg) was administered intraperitoneally 12 h before and immediately after LPS injection and then every 24 h for 3 days. Inflammatory responses, activation of microglia and brain injury were examined 1 and 3 days after LPS injection. LPS injection resulted in brain injury in selective brain areas, including bilateral ventricular enlargement, cell death at the sub- and periventricular areas, loss of O4+ and O1+ oligodendrocyte (OL) immunoreactivity and hypomyelination, as indicated by decreased myelin basic protein immunostaining, in the neonatal rat brain. Minocycline administration significantly attenuated LPS-induced brain injury in these rat brains. The protective effect of minocycline was associated with suppressed microglial activation as indicated by the decreased number of activated microglial cells following LPS stimulation and with consequently decreased elevation of interleukin 1beta and tumor necrosis factor-alpha concentrations induced by LPS and a reduced number of inducible nitric oxide synthase expressing cells. Protection of minocycline was also linked with the reduction in LPS-induced oxidative stress, as indicated by 4-hydroxynonenal positive OLs. The overall results suggest that reduction in microglial activation may protect the neonatal brain from LPS-induced white matter injury and inhibition of microglial activation might be an effective approach for the therapeutic treatment of infection-induced white matter injury.

Identity of an estrogen membrane receptor coupled to a G protein in human breast cancer cells

Although nonclassical estrogen actions initiated at the cell surface have been described in many tissues, the identities of the membrane estrogen receptors (mERs) mediating these actions remain unclear. Here we show that GPR30, an orphan receptor unrelated to nuclear estrogen receptors, has all the binding and signaling characteristics of a mER. A high-affinity (dissociation constant 2.7 nm), limited capacity, displaceable, single binding site specific for estrogens was detected in plasma membranes of SKBR3 breast cancer cells that express GPR30 but lack nuclear estrogen receptors. Progesterone-induced increases and small interfering RNA-induced decreases in GPR30 expression in SKBR3 cells were accompanied by parallel changes in specific estradiol-17beta (E2) binding. Plasma membranes of human embryonic kidney 293 cells transfected with GPR30, but not those of untransfected cells, and human placental tissues that express GPR30 also displayed high-affinity, specific estrogen binding typical of mERs. E2 treatment of transfected cell membranes caused activation of a stimulatory G protein that is directly coupled to the receptor, indicating GPR30 is a G protein-coupled receptor (GPCR), and also increased adenylyl cyclase activity. The finding that the antiestrogens tamoxifen and ICI 182,780, and an environmental estrogen, ortho,para-dichlorodiphenyldichloroethylene (o,p'-DDE), have high binding affinities to the receptor and mimic the actions of E2 has important implications for both the development and treatment of estrogen-dependent breast cancer. GPR30 is structurally unrelated to the recently discovered family of GPCR-like membrane progestin receptors. The identification of a second distinct class of GPCR-like steroid membrane receptors suggests a widespread role for GPCRs in nonclassical steroid hormone actions.

Steinernema aciari sp. n. (Nematoda: Steinernematidae), a new entomopathogenic nematode from Guangdong, China

A new species of entomopathogenic nematode, Steinernema aciari sp. n. was described. It was recovered from a soil sample collected from Haimen town, Shantou district in the eastern coast of Guangdong province, the People's Republic of China during a survey for entomopathogenic nematodes. S. aciari sp. n. belongs to the Steinernema glaseri group. It can be separated from all described Steinernema species by the combined morphological and morphometrical characters of various stages of the nematodes. For male, the new species can be recognized by spicule length (86+/-6.3 microm); spicule tip blunt with a hook-like structure; gubernaculum with a short and Y-shaped cuneus and corpus well-separated posteriorly. For infective juvenile, the combination of the following characters: body length (1113+/-68 microm), distance from anterior end to excretory pore (95+/-3.7 microm), tail length (78+/-5.2 microm), and E % (123+/-7) can be used to differentiate the new species from other nematodes. For female, the tail (conoid with a long mamillate terminus and a distinct postanal swelling) and vulva (slightly protruding from body surface with conspicuous double flapped epiptygma) shapes can be used as diagnostic characters for the new species. The new species can also be distinguished from other Steinernema species by DNA sequences of either a partial 28S rDNA or the internal transcribed spacer regions of rDNA, and from the close related species S. glaseri, Steinernema longicaudum CWL05, and Steinernema guangdongense by cross-breeding test.

Expression of vip1/vip2 genes in Escherichia coli and Bacillus thuringiensis and the analysis of their signal peptides

AIMS

To determine the expression time courses and high expression level of Vip2A(c) and Vip1A(c) in Bacillus thuringiensis, and survey their insecticidal toxicity and insecticidal spectrum.

METHODS AND RESULTS

A kind of new vegetative insecticidal toxin genes encoded by a single operon from B. thuringiensis had been cloned and sequenced. The individual genes, 5-terminus truncated genes and the operon were respectively expressed in Escherichia coli. Only N-terminus deleted Vip2A(c) and Vip1A(c) proteins could be purified by Ni-NTA agarose, while others were processed and their N-terminal signal peptides were cleaved. The individual genes and the operon were also expressed in B. thuringiensis. Both proteins were mostly secreted into the cell supernatants. The expression level of Vip1A(c) was influenced because of the interruption of vip2A(c) gene on the operon. Bioassays showed that neither separate protein nor both performed any toxicity against tested lepidopteran and coleopteran insects.

CONCLUSIONS

Vip2A(c) and Vip1A(c) have similar secretion mechanism in E. coli and B. thuringiensis. Vip1A(c) remained its high expression level only when being expressed with vip2A(c) gene as an operon in B. thuringiensis.

SIGNIFICANCE AND IMPACT OF THE STUDY

Expression of vip2A(c) and vip1A(c) genes in E. coli and B. thuringiensis were investigated. This would help to make clear the secretion mechanism of VIP proteins and study the function of ADP-ribosyltransferase Vip2.

Bipolar Microscissors

The authors present a novel bipolar-coagulation microscissors exclusively designed for microsurgical use which can be applied easily, safely and effectively. The device is particularly helpful in the management (coagulation and cutting) of cerebral microvessels during the resection of brain tumors rich in vascularity or AVMs. The advantages of the instrument are the avoidance of exchanges of bipolar and microscissors under the microscope, reduction of fatigue for the operator, and decreases of operative time and blood loss while still achieving a good result.

Alteration of heme-oxygenase-carbon monoxide pathway in calcified rat vascular smooth muscle cells

OBJECTIVE

The aim of the present study was to investigate the changes in heme-oxygenase (HO)-carbon monoxide (CO)-cyclic guanosine monophosphate (cGMP) pathway in clacified rat vascular smooth muscle cells (VSMCs).

METHODS

Calcification of cultured rat VSMCs was induced by incubation of VSMCs with beta-glycerophosphate. Cellular calcium content, ALP activities and (45)Ca uptake were measured. HO activity, HbCO formation and content of cGMP in VSMCs were determined. Immunocytochemistry for HO-1 expression was observed.

RESULTS

In comparison of control VSMCs, the cellular calcium content, ALP activity and (45)Ca uptake in calcified VSMCs were obviously increased. Immunocytochemistry showed that HO-1 expression was weak and not well distributed in calcified cells as compared to non-calcified VSMCs, but interestingly, there was stronger staining in calcified nodules than in VSMCs. Compared with VSMCs, HO-1 activity in calcified cells decreased by 42.7% [36.4 +/- 2.8 pmol (mg Pr x h)(-1) vs 63.5 x 5.3 pmol (mg Pr x h)(-1), p < 0.01], and HbCO formation decreased by 39.2% (3.38 x 0.69 micromol/mg Pr vs 5.56 +/- 0.48 micromol/mg Pr, p < 0.05). The cGMP content in calcified VSMCs was 78.1% lower than that of non-calcified VSMCs (4.3 +/- 0.51 vs 19.6 +/- 1.2 pmol/mg, p < 0.01).

CONCLUSION

The results showed that HO-CO-cGMP pathway in calcified vascular cells obviously changed, which might contribute to disturbance of vascular function.

Comparison of the expression of Bacillus thuringiensis full-length and N-terminally truncated vip3A gene in Escherichia coli

AIMS

Studies were performed to demonstrate the function of the putative signal peptide of Vip3A proteins in Escherichia coli.

METHODS AND RESULTS

The full-length vip3A-S184 gene was isolated from a soil-isolated Bacillus thuringiensis, and the vip3AdeltaN was constructed by deleting 81 nucleotides at the 5'-terminus of vip3A-S184. Both were transformed and expressed in E. coli. About 19.2% of Vip3A-S184 proteins secreted soluble proteins and others formed inclusion bodies in the periplasmic space. In contrast, the Vip3AdeltaN was insoluble and formed inclusion bodies in the cytoplasm. Bioassay indicated that Vip3A-S184 showed different toxicity against Spodoptera exigua, Helicoverpa armigera and S. litura, but Vip3AdeltaN showed no toxicity to either of them because of the deletion of the first 27 amino acids at the N-terminus.

CONCLUSIONS

The results suggest that the deleted N-terminal sequences were essential for the secretion of Vip3A-S184 protein in E. coli and might be required for toxicity.

SIGNIFICANCE AND IMPACT OF THE STUDY

The function of the putative signal peptide of Vip3A protein in E. coli was investigated. These would be helpful to make clear the unknown secretion pathway of Vip3A protein in B. thuringiensis and determine the receptor-binding domain or toxic fragment of Vip3A-S184 protein.

The effect of vascular endothelial growth factor on the healing of ischaemic skin wounds

The effect of exogenous vascular endothelium growth factor (VEGF) on wound healing in an ischaemic skin flap model was evaluated in this study. Seventy-two Sprague-Dawley rats were used. Normal incisional wound and H-shaped double flaps were used as the wound models. The study was divided into two parts. In Part I, VEGF protein levels were determined from the incisional and H-shaped ischaemic wounds at 12 and 24 h, postoperatively. In Part II, tensile strength and immunohistochemical stains were examined to determine the level of microvessel density (MVD) at 1 and 2 weeks, postoperatively in simple incisional wounds, ischaemic wounds, and ischaemic wounds following 1 ml (1 microg/ml) exogenous VEGF injections into the subcutaneous tissue. The results showed a significantly higher level of VEGF protein in the ischaemic wounds than the incisional wounds. Tensile strength was statistically higher in the incisional wound group and in the ischaemic flap wounds with VEGF treatment compared to the ischaemic flaps with no treatment at 1 week, postoperatively (p>0.05). MVD data indicated that ischaemic wound repair with VEGF treatment had significantly higher MVD than the normal incisional wounds and ischaemic wounds without treatment. We conclude that exogenous application of VEGF can increase early angiogenesis and tensile strength in the ischaemic wound.

[First discovery of Taenia saginata asiatica infection in Yunnan province]

AIM

To investigate the aetiology, species and epidemiological factors of Taenia infection in a pilot area of Lanping County, Yunnan Province.

METHODS

Two patients with taeniasis were treated with antiscolex capsule and praziquantel, respectively. Five local weaning pigs free from tapeworm infection were fed with gravid proglottids obtained from the patients. After 2-3 months, the pigs were necropsied to examine cysticerci. In addition, one pig naturally infected with Taenia was treated as well.

RESULTS

Based on morphological characteristics of the scolex and gravid proglottid of four tapeworms obtained from the patients, the worms were similar to T. saginata. 23 cysticerci recovered from two experimentally infected pigs were found in the livers, omentum majus and mesenterium, and 3 cysticerci were found in the liver and omentum majus in a naturally infected pig as well. The protoscolex of mature Cysticercus had two rows of rudimentary hooklets, one rostellum and four acetabula resembling to C. cellulosae. According to morphological characteristics and the location of cysticerci, the tapeworm was identified as Taenia saginata asiatia.

CONCLUSION

T. saginata asiatica infection was first reported in Yunnan Province.

Effects of adrenomedullin on vascular calcification in rats

OBJECTIVE

The aim of the present study was to investigate the effect of adrenomedullin (ADM) on vascular calcification.

METHODS

The vascular calcification model was established in rats (VND group) by using vitamin D3 (300,000 IU/kg) and nicotine (25 mg/kg, two doses). The effect of liposome-encapsulated ADM was observed. Vascular calcium content, alkaline phosphatase (ALP) activity, ADM in aortic tissue and plasma, binding ability of 125I-ADM for ADM receptor on vascular plasma membrane and content of cAMP in vessels were measured.

RESULTS

Compared with control rats, the aortic calcium content and vascular ALP activity in rats of the VDN group was obviously increased; in addition ADM concentrations in plasma and vessels of rats in VDN group were increased. But the maximum binding sites of 125I-ADM for ADM receptor (Bmax) on vascular plasma membrane in rats of VDN group were significantly decreased compared with control rats. The affinity of 125I-ADM for the ADM receptor was reduced, as shown by the Kd value and vascular cAMP content being reduced in rats of the VDN group compared to the control group. The in vitro response of isolated vessels to ADM incubation was weakened. Administration of empty liposome had no effect on vascular calcification. But administration of ADM significantly decreased vascular calcium content and ALP activity. The Bmax of 125I-ADM for ADM receptors on vascular plasma membrane increased by 17.7% (p < 0.01), and the value of Kd decreased by 36.2% (P < 0.01) in rats treated with ADM as compared with rats of the VDN group. In addition, the vascular cAMP content and the response to ADM in isolated aorta were markedly increased.

CONCLUSION

Vascular calcification induced an alteration of the vascular ADM-ADM receptor-cAMP pathway. Treatment with exogenous ADM inhibited vascular calcification by improving the vascular ADM-ADM receptor-cAMP pathway.

[Functional analysis of SpltMNPV envelope protein SL136]

Our previous research showed that the Spodoptera litura multinucleocapsid nucleopolyhedrovirus (SpltMNPV) Sl136 product had a function to befused with membrane when expressed alone. In this study, the Sl136 and its product were characterized. RT-PCR results showed that Sl136 could be transcribed at 6 hpost infection, indicating it was an early gene. Then the antiserum against SL136 protein was generated and utilized to verify that SL136 was a BV envelope protein, by using SDS-PAGE and Western blot. Two main protein bands in SpltMNPV-infected Sl-zsu-1 cells were detected; their molecular weights were about 86 kD and 65 kD, respectively. It was found that the size of smaller band coincided with amajor band of BV envelope proteins. SL136 protein was transferred to cell surfaces both in SpltMNPV-infected Sl-zsu-1 cells and recombinant Bac-Sl136-infected Hi5 cells, as detected by cell ELISA(cell enzyme-linked immunosorbant assay, CELISA). From the bioassay results, it was found that furin cleavage of SL136 was not necessary for viral propagation, and inhibition of its glycosylation decreased the BV virulence.

Compositional changes of cottonseed hull substrate during P. ostreatus growth and the effects on the feeding value of the spent substrate

The dry matter and composition of cottonseed hull substrate for P. ostreatus cultivation were tested at different growth stages. As protein, cellulose, hemicellulose and lignin were used by P. ostreatus, the compositional profiles of the substrate were changed greatly, but their rates of change varied at different growing stages. The increase of protein content and the reduction of lignocellulose content contributed to the increase in the dry matter digestibility of the spent substrate, making it possibly acceptable as a potential ruminant feed. This could provide an alternative to environmentally sound use of P. ostreatus spent substrate.

Analysis of genes differentially expressed in astrocytes stimulated with lipopolysaccharide using cDNA arrays

We used cDNA arrays to investigate differentially expressed genes in astrocytes challenged with lipopolysaccharide (LPS). Astrocyte cultures were prepared from 1-day-old rat brains. Purified astrocytes were treated with LPS (1 microg/ml) for 2, 8 and 48 h. Differentially expressed genes in these astrocytes were examined with Atlas rat cDNA arrays. At all the three time points studied, three genes were found consistently up-regulated: I-kappaB alpha chain, NF-kappaB, and interferon induced protein. In addition to these three, six other genes were also up-regulated at 2 and 8 h. They were genes encoding vascular cell adhesion protein 1 (VCAM-1), interferon regulatory factor 1 (IRF-1), mitochondrial hydroxymethylglutaryl-CoA synthase (HMG-CoA synthase), aldehyde dehydrogenase 2, macrophage inflammatory protein 1 (MIP-1) and neurotensin receptor 2. At these two time points, three genes were down-regulated: copper-zinc-containing superoxide dismutase 1 (SOD-1), insulin-like growth factor binding protein 1 (IGFBP-1), and insulin-like growth factor binding protein 3 (IGFBP-3). Expression of several differentially expressed genes in cDNA array (I-kappaB, VCAM-1 and MIP-3) were further confirmed by reverse transcription polymerase chain reaction study. The prominently modulated genes could be classified into three categories: nuclear transcription factors, pro-inflammatory cytokines/chemokines and metabolic enzymes. Application of pyrrolidine dithiocarbamate, an inhibitor of nuclear factor-kB (NF-kappaB), prior to LPS stimulation not only prevented up-regulation of NF-kappaB gene expression, but also completely blocked up-regulation of pro-inflammatory cytokine genes (TNF-alpha and interleukin-1beta) and two chemokine genes: CXC chemokine LIX and CC chemokine MIP-3 alpha. These results indicate that both up-regulation of inflammatory cytokine expression and down-regulation of growth factor expression are probably involved in the response of astrocytes upon exposure to LPS.

Pathological, ultrastructural and immunohistochemical observations of adenoma of retinal pigment epithelium

PURPOSE

To Study the clinical, pathological, ultrastructural and immunohistchemical characters of adenoma of the retinal pigment epithelium in order to offer evidence to diagnose this tumor.

METHODS

Routine paraffin slices HE stain, histochemistry PAS and VG stain, transmission electron microscopy, and immunohistochemistry for S-100 and vimentin with LSAB method were used.

RESULTS

The tumor cells were oval and cuboidal in shape. Part of the tumor had a tubular arrangement. Around the sheets of tumors cells there was a large amount of uniform red stick-like substances. The above matter represented positive in PAS stain. Most of the above matter was yellow, while less of the matter showed red in VG stain. Transmission electron microscopy showed that there were tight junctions between tumor cells. Immunohistochemistry showed positive for S-100, negative for vimentin.

CONCLUSIONS

The ultrastructural and immunohistochemical characters of the adenoma of retinal pigment epithelium are consistent with the retinal pigment epithelium.

Sequence analysis of the Spodoptera litura multicapsid nucleopolyhedrovirus genome

The complete Spodoptera litura multicapsid nucleopolyhedrovirus (SpltMNPV) genome contained 139,342 bp with a G+C content of 42.7%, and 141 putative open reading frames (ORFs) or genes of 150 nucleotides or greater that showed minimal overlap. Ninety-six ORFs had homologues in Autographa californica multicapsid nucleopolyhedrovirus (AcMNPV), 16 had homologues in other baculoviruses, and 29 were unique to SpltMNPV. The homologues of ubiquitin and gp37 are fused in SpltMNPV. The genome lacked a homologue of the major budded virus glycoprotein gene gp64, but it contained a homologue of ORF130 of Lymantria dispar multicapsid nucleopolyhedrovirus (LdMNPV). There were two homologues of AcMNPV ORF2 (bro gene), and a DnaJ protein gene (SpltORF39) in which the N-terminus showed homologies with the J domain of DnaJ family proteins. Seventeen homologous regions (hrs) were identified, each containing 2-29 palindromic repeats, with an average length of 534 bp and base content (G+C%) of 33.0.

A longitudinal investigation of aggregate oral intake of copper

Four-day composite solid food and beverage duplicate plates and 1-L samples of drinking water were collected from a stratified random sample of 80 individuals as part of the National Human Exposure Assessment Survey in Maryland. The media were obtained from each participant in up to six equally spaced sampling cycles over a year and analyzed for copper by inductively coupled plasma mass spectrometry. Copper concentrations (microg/kg) and consumption rates (kg/d) of solid food, beverage and drinking water were used to derive average daily aggregate oral intake of copper (microg/d). The mean aggregate copper intake of 263 measurements obtained from 68 people was 923.2 +/- 685.6 microg/d (mean +/- SD). Intake through solid food accounted for the majority of aggregate daily intake of copper contributing 87% on average. According to results from mixed model analysis of variance procedures, the mean log-transformed average daily copper intake in each medium except beverage exhibited significant (P < 0.05) variability among sampling cycles. Between-person variability accounted for 50% of the total variance in aggregate copper intake. As measured by the coefficient of variation, distributions of copper intake consisting of one observation per individual were more variable than the distribution consisting of the long-term average intake for each person. These results suggest that estimates of the fraction of a population at risk from chronic copper deficiency or excess copper intake can be overestimated if based upon short-term measures of copper intake. In addition, these results indicate that longitudinal information is required for accurate assessment of aggregate oral intake of copper for an individual.

Highly toxic and broad-spectrum insecticidal Bacillus thuringiensis engineered by using the transposon Tn917 and protoplast fusion

The chromosome of the Bacillus thuringiensis strain S184 that was toxic against the third instar larvae of Spodoptera litura with the LC(50) of 9.74 microg/ml was successfully integrated into two genes of cyt1Aa and cry11Aa using the transposon Tn917, yielding the primary engineered strain TnX. The strain TnX was highly toxic to the third instar larvae of Culex pipiens fatigans with the LC(50) of 5.12 ng/ml which was 1.82-fold higher than that of B. thuringiensis subsp. israelensis, but lowly toxic to lepidopterous larvae. By the protoplast fusion of the strain TnX and the strain S184-Tet(r) (resistance to tetracycline), the target engineered strain TnY was obtained. Against the third instar larvae of S. litura, the strain TnY LC(50) was of 4.68 micro g/ml and increased by 2.08-fold in comparison with the parent strain S184. Against the third instar larvae of C. pipiens fatigans, the strain TnY LC(50) was of 103.20 ng/ml. The two target genes of cyt1Aa and cry11Aa integrated into the chromosome were extremely stable and had little possibility of a second transposition. It was unclear whether some factors existing in the parent strain, S184, contributed to the high toxicity of the strains TnX and TnY.

Functional dynamics in the active site of the ribonuclease binase

Binase, a member of a family of microbial guanyl-specific ribonucleases, catalyzes the endonucleotic cleavage of single-stranded RNA. It shares 82% amino acid identity with the well-studied protein barnase. We used NMR spectroscopy to study the millisecond dynamics of this small enzyme, using several methods including the measurement of residual dipolar couplings in solution. Our data show that the active site of binase is flanked by loops that are flexible at the 300-micros time scale. One of the catalytic residues, His-101, is located on such a flexible loop. In contrast, the other catalytic residue, Glu-72, is located on a beta-sheet, and is static. The residues Phe-55, part of the guanine base recognition site, and Tyr-102, stabilizing the base, are the most dynamic. Our findings suggest that binase possesses an active site that has a well-defined bottom, but which has sides that are flexible to facilitate substrate access/egress, and to deliver one of the catalytic residues. The motion in these loops does not change on complexation with the inhibitor d(CGAG) and compares well with the maximum k(cat) (1,500 s(-1)) of these ribonucleases. This observation indicates that the NMR-measured loop motions reflect the opening necessary for product release, which is apparently rate limiting for the overall turnover.

Acute exposure to environmental tobacco smoke and heart rate variability

Environmental tobacco smoke (ETS) has been associated with cardiovascular mortality. Pathophysiologic pathways leading from ETS exposure to cardiopulmonary disease are still being explored. Reduced cardiac autonomic function, as measured by heart rate variability (HRV), has been associated with cardiac vulnerability and may represent an important pathophysiologic mechanism linking ETS and risk of cardiac mortality. In this study we evaluated acute ETS exposure in a commercial airport with changes in HRV in 16 adult nonsmokers. We conducted ambulatory electrocardiographic (ECG) monitoring for 8-hr periods while participants alternated 2 hr in nonsmoking and smoking areas. Nicotine and respirable suspended particle concentrations and participants' blood oxygen saturation were also monitored. We calculated time and frequency domain measures of HRV for periods in and out of the smoking area, and we evaluated associations with ETS using comparative statistics and regression modeling. ETS exposure was negatively associated with all measures of HRV. During exposure periods, we observed an average decrement of approximately 12% in the standard deviation of all normal-to-normal heart beat intervals (an estimate of overall HRV). ETS exposures were not associated with mean heart rate or blood oxygen saturation. Altered cardiac autonomic function, assessed by decrements in HRV, is associated with acute exposure to ETS and may be part of the pathophysiologic mechanisms linking ETS exposure and increased cardiac vulnerability.

Genomic structure and promoter characterization of an imprinted tumor suppressor gene ARHI

We have recently identified a maternally imprinted tumor suppressor gene, ARHI (aplysia ras homolog I), the expression of which is lost in ovarian and breast cancers. We have now characterized the genomic structure of the gene including its promoter and the methylation status of its upstream CpG islands. The ARHI gene spans approximately 8 kb containing two exons and one intron. Exon 1 contains 81 non-translated nucleotides, connected to exon 2 with a 3.2-kb intron. The entire protein-coding region is located within exon 2 and encodes a 229-residue small GTP-binding protein belonging to the Ras superfamily. Genomic structure analysis has identified three potential CpG islands. Two of them (CpG island I and II) are located within the promoter and adjacent exon 1 of the ARHI gene. Aberrant methylation of these CpG islands has been detected in breast cancer cells but not in normal epithelial cells, supporting the possibility that appropriate methylation status of the CpG islands in the promoter region may play a role in the downregulation of ARHI gene expression. A TATA box is found 27 bp upstream of the transcription start site associated with several putative transcription factor binding sites. Transient transfection with nested deletion constructs of the 2-kb ARHI promoter regions fused to a luciferase reporter indicated a 121-bp sequence upstream of the transcription initiation site is required for basal promoter activity. Interestingly, this is the region where lower promoter activity has been observed in cancer cells than in normal cells.

[The pathology and DNA quantitative study of renal clear cell carcinoma in children]

OBJECTIVE

To investigate the pathological features of renal clear cell carcinoma (RCCC) in children and its relationship to the DNA content of cancer cells and DNA ploidy.

METHODS

The pathologic morphology of 4 cases of RCCC in children were observed. Using image analysis instruments the quantity of tumor cell DNA was measured.

RESULTS

The cytoplasm of the tumor cells were clear in all four cases. Papillary structures were present in these tumors, of which the papillary structure in two cases was over 50%, three cases had small calcified bodies with prominent bleeding and necrosis. Around tumor the glomerular and tubular of kidney always is normal the average DNA index was 1.31. They presented diploidy, high diploidy or subtetraploidy.

CONCLUSIONS

The specific features of most RCCC in children are clear cytoplasm, most contain papillary structures, calcified bodies, often with bleeding and necrosis. Around tumor the glomerular and tubular of kidney is always normal. The DNA contents of cancer cells present diploidy, high diploidy or subtetraploidy.

[Identification and location of the toxin protein genes in 56 Bacillus thuringiensis isolates]

Polymerase chain reaction was performed to screen Bacillus thuringiensis isolates for cryI, cryIII, and cryV genes with cryI-, cryIII-, and cryV-specific primers respectively. The results indicated that, in the 56 Bt isolates examined, 7 isolates contain cryI gene, 2 isolates contain cryIII gene, and 21 isolates contain both cryI and cryV genes. The cryV gene was located by Southern hybridization in the large plasmid of about 150 MD molecular mass.

Intracellular redistribution of cardiac endothelin-1 receptor in rat during myocardial hypertrophy

OBJECTIVE

In a model of rat cardiac hypertrophy, the changes in the distribution of ET-1 receptors in two subcellular fractions, the sarcolemma and the light vesicles during myocardial hypertrophy were studied.

METHODS

Cardiac hypertrophy was produced by placing a constricting clip around the suprarenal abdominal aorta of rats, and ET-1 receptor was assayed with radioactive analysis method.

RESULTS

It was found that plasma and ventricular ET-1 levels increased significantly on week 2 and week 4 of pressure overload. ET-1 binding studies showed that during myocardial hypertrophy, the maximum binding capacity (B(max)) was increased by 41% (P < 0.01) and 65% (P < 0.01) in sarcolemma in H-2 week and H-4 week groups, but was decreased by 24% (P < 0.01) and 21% (P < 0.01) in light vesicles. The sum of B(max) of sarcolemmal and light vesicle fractions was increased by 33% (P < 0.01) and 57% (P < 0.01) in group H-2 week and H-4 week, respectively.

CONCLUSION

ET-1 receptors in rat heart were externalized from light vesicles to sarcolemma, which may contribute to the development of myocardial hypertrophy.

Chronic ischemia preferentially causes white matter injury in the neonatal rat brain

Chronic ischemic brain injuries were studied in 7- and 14-day-old rat pups, which were subjected to bilateral carotid artery occlusion (BCAO) on postnatal day 1. BCAO preferentially injured white matter in the corpus callosum, subcortex and internal capsule areas while largely spared cortical neurons. White matter rarefaction in the corpus callosum was observed in 12 out of the 17 BCAO rat brains and significantly enlarged lateral ventricles were found in five out of seven P14 BCAO rat brains. These white matter changes were similar to injuries found in newborn infants with periventricular leukomalacia (PVL). White matter injuries in the 7-day-old BCAO rat brain were accompanied with increased activation of microglia/macrophages, as indicated by ED1 and OX42 positive immunostaining. Immature oligodendrocytes in the 7-day-old BCAO rat brain, as indicated by O4+/O1+ staining, were much fewer than in the sham-operated rat brain. Immunostaining for myelin basic protein (MBP) at the fimbria hippocampus and the internal capsule areas in the 7-day-old BACO rat brain was also much less than in the control rat brain. Consistent with the immunostaining data, MBP mRNA expression in the 7-day-old, but not in the 14-day-old, BCAO rat brain was significantly less than in the control rat brain. The overall results suggest that pre-oligodendrocytes and immature oligodendrocytes might be major targets for chronic ischemic insults and activated microglia/macrophages are possibly involved in the process of white matter injury.

[Detection of enterotoxin genes in Bacillus thuringiensis by PCR]

The presence of hemolysin HblA (hblA), enterotoxin BceT (bceT) and enterotoxin S (entS) genes from 45 strains of B. thuringiensis, 4 strains of B. cereus and B. sphaericus have been detected respectively by multiple PCR. The results showed that 95.6% B. thuringiensis strains contain the B component of hblA gene, 91.1% and 93.3% of them contain bceT and entS genes sequences respectively. The enterotoxin productions in all strains have also been analysis using two commercial immunoassay kits(TECRA and RPLA) and it has proved that most of B. thuringiensis stains and the positive B. cereus strain can produce entero toxins during their growth. However, the two hblA sequence positive stains, DBT007 was negative when tested both by RPLA and Tecra, T24 001 was negative when assayed by Tecra and positive by RPLA. One hblA sequence negative strain Dmu39 was negative when tested by RPLA but positive by Tecra. No enterotoxin and enterotoxin gene could be detected in B. thuringiensis DBT248 and the B. sphaericus strains. The results suggest that the potential risk of using B. thuringiensis, as biopesticide needs to be further evaluated.

Role of calcineurin in angiotensin II-induced cardiac myocyte hypertrophy of rats

OBJECTIVE

The present study investigated the role of calcineurin in angiotensin II(AngII) -induced cardiac myocyte hypertrophy of rats.

METHOD

The primary cardiac myocytes were cultured under the standard conditions. The calcineurin activity in AngII-treated cardiomyocytes was tested by using PNPP; protein synethsis rate was assessed by 3H-leucine incorporation; atrial natriuretic factor(ANF) mRNA level was determined by Northern blot analysis. Cell viability was estimated by lactate dehydrogenase (LDH) levels in cultured medium and by dyed cell numbers.

RESULT

After stimulation of 10, 100 and 1 000 nmol/L of AngIi, calcineurin activities in the cardiomyocytes were increased by 13%, 57% (P < 0.05) and 228% (P < 0.01) respectively, compared with control group. Cyclosporin A(CsA), a specific inhibitor of calcineurin, markedly inhibited the calcineurin activity and decreased the 3H-leucine incorporation in AngII-treated cardiomyocytes in a dose-dependent manner. It was also found that CsA slightly reduced the mRNA level of ANF gene in AngII-stimulated cardiomyocytes.

CONCLUSION

During AngII-induced cardiac myocyte hypertrophy, calcineurin signal pathway is activated, and inhibition of the pathway can attenuate AngII-induced cardiac myocyte hypertrophy, which suggests that the calcineurin signal pathway may play an important role in AngII-induced myocardial hypertrophy of rats.