Involvement of the mt1 melatonin receptor in human breast cancer

Two putative melatonin receptors have been described including the cell surface G-protein-linked receptors, mt1 and MT2, and the nuclear retinoic orphan receptor alpha (RORalpha). The mt1 receptor, but not the MT2 receptor, is expressed in human breast tumor cell lines, and melatonin-induced growth suppression can be mimicked by the mt1 and MT2 agonist, AMMTC, and blocked by the antagonist, CBPT. RORalpha receptors are also expressed in MCF-7 breast cancer cells and the putative RORalpha agonist CPG-52608 inhibits MCF-7 cell growth but with a very different dose-response than melatonin. Finally, melatonin and AMMTC, but not CPG-52608, can repress RORalpha transcriptional activity in MCF-7 cells.

Tumor prevention by 9-cis-retinoic acid in the N-nitroso-N-methylurea model of mammary carcinogenesis is potentiated by the pineal hormone melatonin

Our laboratory has demonstrated that treatment of MCF-7 breast cancer cells with melatonin (Mlt) followed 24h later with physiological concentrations of all-trans retinoic acid (atRA) results in apoptosis. These studies were extended into trials using the N-nitroso-N-methylurea (NMU)-induced rat mammary tumor model. Initial studies conducted by feeding the animals 9-cis-retinoic acid (9cRA in the chow) and administering melatonin by subcutaneous injection in the late afternoon demonstrated that the combination of Mlt and 9cRA was able to significantly prevent tumor development, and that the combination was more efficacious that either Mlt or 9cRA alone. In this report, we conducted studies to determine if lower doses of 9cRA could be used in combination with Mlt while still maintaining anti-tumor activity and if the route of administration of 9cRA (bolus (gavage) v.s. chronic (chow) routes) affected its interaction with Mlt. The studies presented here demonstrate that significantly reduced doses of 9cRA can be used in combination with Mlt while maintaining anti-tumor efficacy. Furthermore, our studies demonstrate that 9cRA is equally effective when it is administered chronically (chow) or as a bolus (gavage). These data demonstrate that the combined use of Mlt and 9cRA produces additive or synergistic effects, which are more efficacious than 9cRA alone. This combination of Mlt and 9cRA could be a potentially useful clinical treatment regimen for breast cancer since it allows the use of lower doses of retinoic acid, thus, avoiding the toxic side effects associated with the use of high dose retinoids.

Radioimmunotherapy for model B cell malignancies using 90Y-labeled anti-CD19 and anti-CD20 monoclonal antibodies

In recent years, radioimmunotherapy (RIT) with beta(-) particle emitting radionuclides targeting the CD20 antigen on B cells in the treatment of non-Hodgkin's lymphoma has provided the most compelling human clinical data for the success of RIT. CD19, like CD20, is an antigen expressed on the surface of cells of the B lineage, and CD19 may provide an alternative target for radioimmunotherapy of B cell neoplasms. CD19 has been largely overlooked as a target for conventional 131I RIT, because the antigen rapidly internalizes upon binding of antibody, resulting in catabolism and significant release of 131I. Such modulation may be an advantage to RIT with radiometals such as 90Y, 177Lu, 213Bi and 225Ac. Herein, we have compared beta(-) particle RIT with antibodies targeting either CD19 or CD20. The anti-CD19 and anti-CD20 antibodies, B4 or C2B8, respectively, were appended with the SCN-CHX-A''-DTPA bifunctional chelating agent and labeled with 90Y. In the tumor model used, there were three times as many CD20 target sites on lymphoma cells as compared to CD19 sites (62000 vs 20000 binding sites, respectively). We compared the efficacy of the 90Y-labeled antibodies to reduce lymphoma in a nude mouse xenograft solid tumor model, after measurable lymphoma appeared. Reduction in tumor size began at day 3 in all three 90Y-treated groups, but tumor began to recur in many animals 9 days after the treatments. There was one cure in each specific treatment group. In contrast, the tumor in the two control groups showed no regression. There was a significant prolongation of median survival time from xenograft (P < 0.0001) in all the 90Y-labeled antibody construct-treated groups (32 days for 0.15 mCi 90Y-B4; 26 days for 0.20 mCi 90Y-C2B8, and 23 days for 0.15 mCi 90Y-C2B8) in comparison to the two control groups (11 days for 0.02 mg of C2B8 and 9 days for untreated growth controls). Specificity of the radioimmunotherapy was also shown. In conclusion, 90Y-labeled anti-CD19 antibody has efficacy comparable to 90Y-labeled anti-CD20 antibody in the treatment of mice bearing human lymphoma xenografts. These data suggest that CD19-targeted RIT merits further study.

Moloney murine leukemia virus integrase protein augments viral DNA synthesis in infected cells

Mutations in the IN domain of retroviral DNA may affect multiple steps of the virus life cycle, suggesting that the IN protein may have other functions in addition to its integration function. We previously reported that the human immunodeficiency virus type 1 IN protein is required for efficient viral DNA synthesis and that this function requires specific interaction with other viral components but not enzyme (integration) activity. In this report, we characterized the structure and function of the Moloney murine leukemia virus (MLV) IN protein in viral DNA synthesis. Using an MLV vector containing green fluorescent protein as a sensitive reporter for virus infection, we found that mutations in either the catalytic triad (D184A) or the HHCC motif (H61A) reduced infectivity by approximately 1,000-fold. Mutations that deleted the entire IN (DeltaIN) or 34 C-terminal amino acid residues (Delta34) were more severely defective, with infectivity levels consistently reduced by 10,000-fold. Immunoblot analysis indicated that these mutants were similar to wild-type MLV with respect to virion production and proteolytic processing of the Gag and Pol precursor proteins. Using semiquantitative PCR to analyze viral cDNA synthesis in infected cells, we found the Delta34 and DeltaIN mutants to be markedly impaired while the D184A and H61A mutants synthesized cDNA at levels similar to the wild type. The DNA synthesis defect was rescued by complementing the Delta34 and DeltaIN mutants in trans with either wild-type IN or the D184A mutant IN, provided as a Gag-IN fusion protein. However, the DNA synthesis defect of DeltaIN mutant virions could not be complemented with the Delta34 IN mutant. Taken together, these analyses strongly suggested that the MLV IN protein itself is required for efficient viral DNA synthesis and that this function may be conserved among other retroviruses.

An isothermal titration calorimetric method to determine the kinetic parameters of enzyme catalytic reaction by employing the product inhibition as probe

An isothermal titration calorimetric (ITC) method was developed to measure the kinetic parameters of ribonuclease A catalytic hydrolysis of cytidine 2',3'-cyclic monophosphate. Employing the inhibition of product as a probe, the K(m), K(i), k(c), and DeltaH(m) can be determined by two simple calorimetric measurements. First, the substrate was titrated into the cell containing high concentration of enzyme. The molar reaction heat was calculated from the titration peak area divided by substrate moles per titration, and the initial catalytic reaction rate in the presence of various concentrations of product can be calculated from the peak height and the molar reaction heat. From Michaelis-Menten function in the presence of inhibitors, the relationship between K(m) and K(i) can be obtained. Then, the dissociation constant, which is equal to K(i), was measured by a regular ITC experiment. Thus, K(m) and k(c) can be calculated. The method developed here can be applied in other enzyme catalytic systems with inhibitive products.

Microtubule assembly after treatment of pig oocytes with taxol: correlation with chromosomes, gamma-tubulin, and MAP kinase

In this study, taxol was used as a tool to study the correlation of microtubule assembly with chromosomes, gamma-tubulin and phosphorylated mitogen-activated protein (MAP) kinase in pig oocytes at different maturational stages. Taxol treatment did not affect meiotic resumption and chromosome condensation but inhibited/disrupted chromosome alignment at the metaphase plate and bipolar spindle formation and thus meiotic progression. Microtubules were co-localized with chromosomes and were found to emanate from the chromosomes in taxol-treated oocytes, suggesting that chromosomes may serve as a source of microtubule organization. In addition, the concentric emanation of microtubules within the chromosome-surrounded area in taxol-treated oocytes suggests that microtubule emanation from the chromosomes may be directed by other microtubule-organizing material. The formation of one large spindle or >/=2 spindles in oocytes after taxol removal shows that minus end microtubule-organizing material can be normally located on both sides of chromosomes only when the chromosomes are aligned on the metaphase plate. The co-localization of gamma-tubulin and phosphorylated MAP kinase with microtubule assembly in both control and taxol-treated oocytes suggests that these two proteins are associated microtubule-nucleating material in pig oocytes. However, Western blot analysis showed that neither cytoplasmic microtubule aster formation nor extensive microtubule assembly in the chromosome region induced by taxol was caused by super-activation of MAP kinase. Taxol also induced microtubule assembly depending on chromosome distribution in the first polar body. The results suggest that chromosomes are always co-localized with microtubules and that emanation of microtubules from the chromosomes may be regulated/directed by microtubule-organizing material including gamma-tubulin and phosphorylated MAP kinase in pig oocytes.

Developmental potential of porcine nuclear transfer embryos derived from transgenic fetal fibroblasts infected with the gene for the green fluorescent protein: comparison of different fusion/activation conditions

The in vitro developmental potential of porcine nuclear transfer (NT) embryos was evaluated. Oocytes were matured for 42-44 h, and metaphase II-oocytes were enucleated. Fetal fibroblasts infected with the enhanced green fluorescent protein (EGFP) gene were serum-starved for 3-5 days. A single cell was injected into the perivitelline space of the enucleated oocytes. The reconstructed oocytes were allocated to different fusion and activation conditions. In experiment 1, two different fusion/activation conditions were compared: two pulses of 1.2 kV/cm for 30 microsec (group A), or one pulse of 1.6 kV/cm for 30 microsec followed in 30 min by one pulse of 1.2 kV/cm for 30 microsec (group B). Parthenogenetic controls were created by using the group A parameter. The fusion rate in group A (mean +/- SEM, 68.4% +/- 3.9%) was higher (P < 0.05) than in group B (59.4% +/- 2.3%). The rates of cleavage (50.1% +/- 4.6% to 62.8% +/- 5.5%) were not different among control and treatment groups. However, the rate of parthenogenetic control embryos developing to the blastocyst stage (18.1% +/- 3.1%) was higher (P < 0.05) than the rate of NT embryos (5.9% +/- 1.7% and 4.9% +/- 2.5%). In experiment 2, we compared two pulses of 1.2 kV/cm (group C) versus two pulses of 1.3 kV/cm (group D). For two control groups, the same pulses as those given to group C or D, respectively, were supplied. The fusion rate in group D (70.6% +/- 4.2%) was higher (P < 0.05) than in group C (58.9% +/- 2.7%). The cleavage rates were not different among control and treatment groups (58.1% +/- 8.1% to 73.6% +/- 6.0%). However, the rate of embryos developing to the blastocyst stage in group D (3.5% +/- 1.7%) was lower (P < 0.05) than in controls and group C (11.4% +/- 2.0% to 16.4% +/- 1.1%). In experiment 3, we examined whether the presence of cytochalasin B (CB) during donor cell injection affects the development of NT embryos. The fusion rate of oocytes in the group with CB (78.4% +/- 1.4%) was higher (P < 0.05) than in the group without CB (70.9% +/- 0.2%). The cleavage rate of the control group (85.5% +/- 4.9%) was higher (P < 0.05) than those of the treatment groups (61.6% +/- 2.7% and 63.9% +/- 4.3%). However, the rates of embryos developing to the blastocyst stage (8.1% +/- 2.5% to 19.1% +/- 6.0%) and the mean cell number of blastocysts (29.4 +/- 5.2 to 45.7 +/- 6.4) were not different among control and treatment groups. Green fluorescence was observed at all stages in NT embryos. These results indicate that two pulses of 1.2 kV/cm are enough for fusion/activation of NT embryos to develop to the blastocyst stage, and that the presence of CB during donor cell injection is not necessary for early development of NT embryos.

Feasibility of producing porcine nuclear transfer embryos by using G2/M-stage fetal fibroblasts as donors

The type of donor cell most suitable for producing cloned animals is one of the topics under debate in the field of nuclear transfer. To provide useful information to answer this question, G2/M- and G0/G1-stage fetal fibroblasts were used as donor cells for nuclear transfer. In vitro-matured oocytes derived from abattoir ovaries were used as recipient cytoplasts. In both groups, nuclear envelope breakdown and premature chromosome condensation were completed within 1-2 h after donor cells were injected into the cytoplasm of oocytes. Microtubules were organized around condensed chromosomes and formed a spindle within 1-1.5 h after activation. Decondensation of chromosomes could be seen within 2-4 h after activation. Reformation of the new nuclear envelope occurred 4-6 h after activation and was followed by nuclear swelling and formation of a pronucleus-like structure (PN) 8-12 h after activation. Most (80.6%) of the reconstructed oocytes derived from G2/M cells extruded polar body-like structures (PB). However, a much lower frequency of PB (21.7%) was observed in the reconstructed oocytes derived from G0/G1 donors. A variety of PN and PB combinations were observed in reconstructed oocytes derived from G2/M-stage donors, including 1PN+0PB, 1PN+1PB, 1PN+2PB, 2PN+0PB, 2PN+1PB, 2PN+2PB, and 3PN+1PB. Chromosomes of most embryos (10/13) derived from G2/M stage were diploid. The percentage of cleavage and blastocysts and the average nuclear number of blastocysts in the G2/M and G0/G1 groups were not different. These results demonstrate that the G2/M stage can be morphologically remodeled by cytoplasm of MII oocytes in pigs. To maintain normal ploidy, the extra chromosomes derived from G2/M-stage cells could be expelled by oocytes as a second polar body. G2/M-stage fibroblast nuclei could direct reconstructed embryos to develop to the blastocyst stage.

Identification and antimicrobial susceptibility of Alcaligenes xylosoxidans isolated from patients with cystic fibrosis

In the past decade, potential pathogens, including Alcaligenes species, have been increasingly recovered from cystic fibrosis (CF) patients. Accurate identification of multiply antibiotic-resistant gram-negative bacilli is critical to understanding the epidemiology and clinical implications of emerging pathogens in CF. We examined the frequency of correct identification of Alcaligenes spp. by microbiology laboratories affiliated with American CF patient care centers. Selective media, an exotoxin A probe for Pseudomonas aeruginosa, and a commercial identification assay, API 20 NE, were used for identification. The activity of antimicrobial agents against these clinical isolates was determined. A total of 106 strains from 78 patients from 49 CF centers in 22 states were studied. Most (89%) were correctly identified by the referring laboratories as Alcaligenes xylosoxidans. However, 12 (11%) strains were misidentified; these were found to be P. aeruginosa (n = 10), Stenotrophomonas maltophilia (n = 1), and Burkholderia cepacia (n = 1). Minocycline, imipenem, meropenem, piperacillin, and piperacillin-tazobactam were the most active since 51, 59, 51, 50, and 55% of strains, respectively, were inhibited. High concentrations of colistin (100 and 200 microg/ml) inhibited 92% of strains. Chloramphenicol paired with minocycline and ciprofloxacin paired with either imipenem or meropenem were the most active combinations and inhibited 40 and 32%, respectively, of strains. Selective media and biochemical identification proved to be useful strategies for distinguishing A. xylosoxidans from other CF pathogens. Standards for processing CF specimens should be developed, and the optimal method for antimicrobial susceptibility testing of A. xylosoxidans should be determined.

Production of nuclear transfer-derived swine that express the enhanced green fluorescent protein

The ability to add or delete specific genes in swine will likely provide considerable benefits not just to agriculture but also to medicine, where pigs have potential as models for human disease and as organ donors. Here we have transferred nuclei from a genetically modified fibroblast cell line to porcine oocytes, matured in vitro under defined culture conditions, to create piglets expressing enhanced green fluorescent protein. The nuclear transfer-derived piglets were of normal size, although some mild symptoms of "large offspring syndrome" were evident. These experiments represent a next step towards creating swine with more useful genetic modifications.

Transgenic pigs produced using in vitro matured oocytes infected with a retroviral vector

Here we report the production of transgenic pigs that express enhanced green fluorescent protein (eGFP). Porcine oocytes were matured in vitro in a serum-free, chemically defined maturation medium, subsequently infected with a replication deficient pseudotyped retrovirus, fertilized and cultured in vitro before being transferred to a recipient female. Two litters were born from these embryo transfers; one pig from each litter was identified as transgenic and both expressed eGFP. From a tool in basic research to direct applications in production agriculture, domestic livestock capable of expressing foreign genes have many scientific applications.

Development of porcine embryos and offspring after intracytoplasmic sperm injection with liposome transfected or non-transfected sperm into in vitro matured oocytes

The objective of this study was to evaluate in vitro and in vivo development of porcine in vitro matured (IVM) porcine oocytes fertilised by intracytoplasmic sperm injection (ICSI) and the possibility of producing transgenic embryos and offspring with this procedure. Activated ICSI oocytes had a higher pronuclear formation than non-activated ICSI oocytes (mean 64.8+/-17.3% vs 28.5+/-3.4%, p<0.05). When the zygotes with two pronuclei were cultured to day 2, there was no difference (p<0.05) in the cleavage rate (mean 60.0+/-7.0% vs 63.3+/-12.7%) between the two groups. The blastocyst rate in the activation group was significantly higher than that in the non-activation group (mean 30.0+/-11.6% vs 4.6+/-4.2%, p<0.05). After injection of the sperm transfected with DNA/liposome complex, destabilised enhanced green fluorescent protein (d2EGFP) expression was not observed on day 2 in either cleaved or uncleaved embryos. But from day 3, some of the embryos at the 2-cell to 4-cell stage started to express d2EGFP. On day 7, about 30% of cleaved embryos, which were in the range of 2-cell to blastocyst stage, expressed d2EGFP. However, for the IVF oocytes inseminated with sperm transfected with DNA/liposome complex, and for oocytes injected with sperm transfected with DNA/liposome complex, and for oocytes injected with DNA/liposome complex following insemination with sperm not treated with DNA/liposome complex, none of the embryos expressed d2EGFP. Sixteen day 4 ICSI embryos derived from sperm not treated with DNA/liposome complex were transferred into a day 3 recipient. One recipient delivered a female piglet with normal birthweight. After transfer of the ICSI embryos derived from sperm transfected with DNA/liposome complex, none of the four recipients maintained pregnancy.

Development and expression of the green fluorescent protein in porcine embryos derived from nuclear transfer of transgenic granulosa-derived cells

Nuclear transfer (NT) techniques have advanced in the last few years, and cloned animals have been produced from somatic cells in several species including pig. In this study we examined the feasibility of using granulosa-derived cells (GCs) as donor cells combined with a microinjection procedure to transfer those nuclei. In vitro matured oocytes were enucleated by aspirating the first polar body and adjacent cytoplasm. Mural GCs infected with an enhanced green fluorescence protein (EGFP) gene were serum-starved (0.5% serum, 7 days), injected directly into cytoplasm of enucleated oocytes and the oocytes were electrically activated. The reconstructed embryos were cultured for 7 days and stained with Hoechst 33342 to determine the number of nuclei. Non-manipulated oocytes were electrically activated and cultured as controls. At 9 h post-activation, the pronuclear formation rates were 78.7+/-3.7% in NT and 97.4+/-4.4% in controls at 9 h post-activation. After 7 days culture, the cleavage rates were 24.5+/-7.2% in NT and 79.3+/-5.6% in controls. The blastocysts formation rates were 4.9+/-2.4% in NT and 26.8+/-3.8% in controls. To examine the effect of activation time on development of NT embryos, oocytes were activated at 0-0.5, 1-2, or 3-4 h post-injection. At 18 h post-activation the pronuclear formation rates were higher (62.5+/-7.3%) in the 3-4 h group as compared to the 0-0.5 h (22.0+/-12.5%) or 1-2h (44.5+/-6.3%) groups (P<0.05). However, the cleavage rates (9.6+/-4.6 to 10.7+/-4.2%) and the blastocysts formation rates (1.2+/-2.4 to 4.9+/-3.7%) were not different among treatments (P>0.05). The mean cell number of blastocysts was 15.7+/-5.7 in NT and 25.3+/-24.7 in controls. Green fluorescence was observed in roughly half of the embryos from the one-cell to the blastocyst stage. These results indicate that granulosa-derived cell nuclei can be remodeled in the cytoplasm of porcine oocytes, and that the reconstructed embryos can develop to the blastocyst stage. In addition, EGFP can be used as a marker for gene expression of donor nuclei.

Relationship between skin microbial counts and surgical site infection after neurosurgery

A prospective study was performed to describe the density of bacterial counts on the skin of neurosurgical patients and examine the association between total colony-forming unit (cfu) counts of skin flora at the operative site and surgical site infection (SSI). Two skin cultures were obtained, immediately before and after skin preparation, from the operative sites of 609 neurosurgical patients. SSI surveillance that used Centers for Disease Control/National Nosocomial Infection Surveillance definitions was performed. Predictors for high bacterial counts and SSI among craniotomies were analyzed by means of logistic regression. Neither pre- nor postpreparation counts were associated with SSI. Other SSI risk factors were obesity (relative risk [RR], 2.5), duration of surgery (RR, 1.3 for every additional 30 minutes) and age (RR, 0.7 for each additional 10 years). Duration of skin preparation was not correlated with postpreparation cfu counts. We were unable to detect an association between preoperative bacterial skin counts and SSI.

Antioxidants stimulate meiosis resumption, but inhibit mitogen-activated protein kinase phosphorylation and further cell cycle progression in porcine oocytes

In the present study the effects of two cell-permeant antioxidants, 2(3)-tert-butyl-4-hydroxyanisole (BHA) and nordihydroguaiaretic acid (NDGA), on porcine oocyte meiosis resumption, chromatin behaviour and spindle assembly were investigated. The antioxidants BHA and NDGA stimulated meiosis resumption in a dose-dependent manner in both cumulus-enclosed and denuded porcine oocytes. After in vitro culture for 8 h, few oocytes underwent germinal vesicle breakdown (GVBD) in control groups, whereas GVBD occurred in high percentages of oocytes treated with BHA or NDGA at concentrations that inhibit GVBD in rodent oocytes, although mitogen-activated protein (MAP) kinase was not phosphorylated as revealed by Western immunoblots. Orcein staining and fluorescein isothiocyanate-anti-alpha-tubulin labelling showed that chromosome and spindle formation, respectively, and further meiosis progression were inhibited 20 and 25 h after culture. Instead, chromatin was highly condensed or existed in scattered condensed clusters. Correspondingly, MAP kinase phosphorylation was inhibited by both BHA and NDGA in a dose-dependent manner. The inhibitory effects of BHA on meiosis completion and MAP kinase phosphorylation was reversible. These results suggest that, unlike in rodent oocytes, antioxidants stimulate GVBD in the absence of MAP kinase activation, but inhibit MAP kinase phosphorylation, meiotic apparatus formation and thus the further progression of the meiosis of porcine oocytes.

Cutting edge: Identification of a hybrid cytokine consisting of IL-7 and the beta-chain of the hepatocyte growth factor/scatter factor

Pre-pro-B cell growth-stimulating factor (PPBSF) is a heterodimer of IL-7 and a 30-kDa cofactor. Unlike monomeric IL-7, PPBSF selectively induces proliferation and differentiation of pre-pro-B cells and up-regulates IL-7Ralpha-chain expression. Here we clone the PPBSF cofactor from bone marrow stromal cells and identify it as a variant beta-chain of hepatocyte growth factor (HGF), a pleiotropic cytokine homologous to plasminogen that regulates cell growth, motility, and morphogenesis. We further demonstrate that, in the presence of low m.w. heparin sulfate-derived oligosaccharides, rHGFbeta combines with rIL-7 to form a biologically active heterodimer having the properties of PPBSF. The results indicate that PPBSF is a novel form of cytokine (hybrid cytokine) consisting of the bioactive components of two unrelated cytokines. Based on its heparin-binding and mitogenic properties, we postulate that the HGFbeta-chain in PPBSF enables IL-7 to participate in cognate interactions at the stromal cell surface and to transduce signals effectively at low levels of IL-7R.

Dipeptide frequency/bias analysis identifies conserved sites of nonrandomness shared by cysteine-rich motifs

This report describes the application of a simple computational tool, AAPAIR.TAB, for the systematic analysis of the cysteine-rich EGF, Sushi, and Laminin motif/sequence families at the two-amino acid level. Automated dipeptide frequency/bias analysis detects preferences in the distribution of amino acids in established protein families, by determining which "ordered dipeptides" occur most frequently in comprehensive motif-specific sequence data sets. Graphic display of the dipeptide frequency/bias data revealed family-specific preferences for certain dipeptides, but more importantly detected a shared preference for employment of the ordered dipeptides Gly-Tyr (GY) and Gly-Phe (GF) in all three protein families. The dipeptide Asn-Gly (NG) also exhibited high-frequency and bias in the EGF and Sushi motif families, whereas Asn-Thr (NT) was distinguished in the Laminin family. Evaluation of the distribution of dipeptides identified by frequency/bias analysis subsequently revealed the highly restricted localization of the G(F/Y) and N(G/T) sequence elements at two separate sites of extreme conservation in the consensus sequence of all three sequence families. The similar employment of the high-frequency/bias dipeptides in three distinct protein sequence families was further correlated with the concurrence of these shared molecular determinants at similar positions within the distinctive scaffolds of three structurally divergent, but similarly employed, motif modules.

Quinoline-4-acetamides as sPLA(2) inhibitors

Quinoline-4-acetamides were designed as potential phospholipase A(2) inhibitors by structural based method and synthesized. The chemical structures of the obtained compounds were confirmed by elemental analyses, 1H NMR and MS. Preliminary bioassay study shows that quinoline-4-acetamides display certain inhibition to sPLA(2).

Translocation of active mitochondria during pig oocyte maturation, fertilization and early embryo development in vitro

The distribution of active mitochondria during pig oocyte maturation, fertilization and early embryo development in vitro was revealed by using MitoTracker Green staining and confocal laser scanning microscopy. The regulation of mitochondrial translocation by microfilaments and microtubules was also studied. In oocytes collected from small follicles, strong staining of active mitochondria was observed in the cell cortex. Accumulation of active mitochondria in the peripheral cytoplasm and around the germinal vesicles was characteristic of fully grown oocytes collected from large follicles. Mitochondria accumulated in the perinuclear area during meiotic progression from germinal vesicle breakdown (GVBD) to anaphase I. Larger mitochondrial foci were formed and moved to the inner cytoplasm in mature oocytes. Compared with the oocytes matured in vivo, in which large mitochondrial foci were distributed throughout the cytoplasm, mitochondria were not observed in the central cytoplasm in most of the oocytes matured in vitro. Strong staining of mitochondria was observed in the first polar bodies in metaphase II oocytes. In fertilized eggs, active mitochondria aggregated in the pronuclear region. Perinuclear clustering and a cortical ring were the most marked features of early cleavage. Active mitochondria were distributed in both inner cell mass cells and trophectoderm cells of the blastocysts. Disassembly of microtubules with nocodazole inhibited both mitochondrial aggregations to the germinal vesicle area and their inward movement to the inner cytoplasm during oocyte maturation, as well as the translocation of mitochondria to the peri-pronuclear region during fertilization, whereas disruption of microfilaments by cytochalasin B had no effects. These data indicate that: (i) oocyte maturation, fertilization and early embryo development in pigs are associated with changes in active mitochondrial distribution; (ii) mitochondrial translocation is mediated by microtubules, but not by microfilaments; and (iii) in vitro maturation conditions may cause incomplete movement of mitochondria to the inner cytoplasm and thus affect cytoplasmic maturation.

Translocation of active mitochondria during pig oocyte maturation, fertilization and early embryo development in vitro

The distribution of active mitochondria during pig oocyte maturation, fertilization and early embryo development in vitro was revealed by using MitoTracker Green staining and confocal laser scanning microscopy. The regulation of mitochondrial translocation by microfilaments and microtubules was also studied. In oocytes collected from small follicles, strong staining of active mitochondria was observed in the cell cortex. Accumulation of active mitochondria in the peripheral cytoplasm and around the germinal vesicles was characteristic of fully grown oocytes collected from large follicles. Mitochondria accumulated in the perinuclear area during meiotic progression from germinal vesicle breakdown (GVBD) to anaphase I. Larger mitochondrial foci were formed and moved to the inner cytoplasm in mature oocytes. Compared with the oocytes matured in vivo, in which large mitochondrial foci were distributed throughout the cytoplasm, mitochondria were not observed in the central cytoplasm in most of the oocytes matured in vitro. Strong staining of mitochondria was observed in the first polar bodies in metaphase II oocytes. In fertilized eggs, active mitochondria aggregated in the pronuclear region. Perinuclear clustering and a cortical ring were the most marked features of early cleavage. Active mitochondria were distributed in both inner cell mass cells and trophectoderm cells of the blastocysts. Disassembly of microtubules with nocodazole inhibited both mitochondrial aggregations to the germinal vesicle area and their inward movement to the inner cytoplasm during oocyte maturation, as well as the translocation of mitochondria to the peri-pronuclear region during fertilization, whereas disruption of microfilaments by cytochalasin B had no effects. These data indicate that: (i) oocyte maturation, fertilization and early embryo development in pigs are associated with changes in active mitochondrial distribution; (ii) mitochondrial translocation is mediated by microtubules, but not by microfilaments; and (iii) in vitro maturation conditions may cause incomplete movement of mitochondria to the inner cytoplasm and thus affect cytoplasmic maturation.

Clonal Lines of Transgenic Fibroblast Cells Derived from the Same Fetus Result in Different Development When Used for Nuclear Transfer in Pigs1

Different factors are believed to influence the outcome of nuclear transfer (NT) experiments. Besides the cell cycle stage of both recipient cytoplast and donor karyoplast, the origin of the donor cells (embryonic, fetal, and adult) is of interest. We compared in vitro development of NT embryos derived from small serum-starved (G0) or small cycling (G1) porcine fetal fibroblast cells. Serum starvation did not have a positive effect on cleavage rate or the percentage of embryos that developed to the morula and blastocyst stages. Next, we investigated the development of porcine NT embryos derived from different transgenic clonal cell lines that had originated from the same fetus. When different clonal lines of fetal fibroblasts were fused to enucleated metaphase II oocytes, differences in fusion rates as well as in development to the morula and blastocyst stages were observed (P < 0.05). When oocytes derived from sow ovaries were used as recipient cytoplasts, significantly better cleavage (P = 0.03) and blastocyst formation (P < 0.014) was obtained when compared with oocytes derived from gilts. Our data indicate that not only different cell lines, but also different clones derived from one primary cell line, result in different development when used for NT. In addition, the use of sow oocytes as a cytoplast source also improves the efficiency of NT experiments.

Cytoplasmic changes in relation to nuclear maturation and early embryo developmental potential of porcine oocytes: effects of gonadotropins, cumulus cells, follicular size, and protein synthesis inhibition

Morphological and biochemical changes indicative of cytoplasmic maturation in relation to nuclear maturation progression and early embryo developmental potential was studied. Fluorescently labeled microfilaments and cortical granules were visualized by using laser scanning confocal microscopy. The mitogen-activated protein (MAP) kinase phosphorylation and cyclin B1 levels were revealed by Western blot. With the maturation of oocytes, cortical granules and microfilaments were localized at the cell cortex. A cortical granule-free domain (CGFD) and an actin-thickening area were observed over both the MII spindle of a mature oocyte and chromosomes of a nocodazole-treated oocyte, suggesting that chromosomes, but not the spindle, determined the localization of CGFD and actin-thickening area. In oocytes that are incompetent to resume meiosis, as indicated by the failure of germinal vesicle breakdown (GVBD), peripheral localization of cortical granules and microfilaments, phosphorylation of MAP kinase and synthesis of cyclin B1 did not occur after 44 hr in vitro. These cytoplasmic changes were also blocked when GVBD of meiotically competent oocytes was inhibited by cycloheximide. Culture of oocytes in a chemically defined medium showed that biological factors such as gonadotropins, cumulus cells and follicle size affected both nuclear and cytoplasmic maturation as well as embryo developmental potential. Absence of gonadotropins or removal of cumulus cells alone did not significantly influence GVBD or cyclin B1 levels, but decreased the final maturation and developmental ability of oocytes. A combination of gonadotropin absence and cumulus removal decreased GVBD, MAP kinase phosphorylation and embryo development. A high proportion of oocytes derived from small follicles were able to resume meiosis, synthesize cyclin B(1), phosphorylate MAP kinase and translocate CGs, but their maturation and embryo developmental ability were limited. Removal of cumulus cells from small follicle-derived oocytes severely affected their ability to undergo cytoplasmic and nuclear maturation.

Protein ligand docking based on empirical method for binding affinity estimation

An empirical protein-ligand binding affinity estimation method, SCORE, was incorporated into a popular docking program, DOCK4. The combined program, ScoreDock, was used to reconstruct the 200 protein-ligand complex structures and found to give good results for the complexes with high binding affinities. A quality assessment method for docking results from ScoreDock was developed based on the whole test set and tested by additionally selected complexes. The method significantly improves the docking accuracy and was shown to be reliable in docking quality assessment. As a docking tool in structural based drug design, ScoreDock can screen out final hits directly based on the predicted negative logarithms of dissociation equilibrium constants of protein-ligand complexes, and can explicitly deal with structure water molecules, as well as metal atoms.

Assessment of two hand hygiene regimens for intensive care unit personnel

OBJECTIVE

To compare skin condition and skin microbiology among intensive care unit personnel using one of two randomly assigned hand hygiene regimens: a 2% chlorhexidine gluconate (CHG)-containing traditional antiseptic wash and a waterless handrub containing 61% ethanol with emollients (ALC).

DESIGN

Prospective, randomized clinical trial.

SETTING

Two critical care units (medical and surgical) in a large, metropolitan academic health center in Manhattan.

SUBJECTS

Fifty staff members (physicians, nurses, housekeepers, respiratory therapists) working full time in the intensive care unit.

INTERVENTIONS

One of two hand hygiene regimens randomly assigned for four consecutive weeks.

MEASUREMENTS AND MAIN RESULTS

The two outcomes were skin condition (measured by two tools: Hand Skin Assessment form and Visual Skin Scaling form) and skin microbiology. Samples were obtained at baseline, on day 1, and at the end of wks 2 and 4. Participants in the ALC group had significant improvements in the Hand Skin Assessment scores at wk 4 (p = 0.04) and in Visual Skin Scaling scores at wks 3 (p = 0.01) and 4 (p = 0.0005). There were no significant differences in numbers of colony-forming units between participants in the CHG or ALC group at any time period. The ALC regimen required significantly less time than the CHG regimen (mean: 12.7 secs and 21.1 secs, respectively; p = 0.000) and resulted in a 50% reduction in material costs.

CONCLUSIONS

Changes in hand hygiene practices in acute care settings from the traditional antiseptic wash to use of plain, mild soap and an alcohol-based product should be considered. Further research is needed to examine the association between use of antiseptic products for hand hygiene of staff and reductions in nosocomial infection rates among patients.

Dynamic events are differently mediated by microfilaments, microtubules, and mitogen-activated protein kinase during porcine oocyte maturation and fertilization in vitro

The role of microfilaments, microtubules, and mitogen-activated protein (MAP) kinase in regulation of several important dynamic events of porcine oocyte maturation and fertilization is described. Fluorescently labeled microfilaments, microtubules, and cortical granules were visualized using either epifluorescence microscopy or laser scanning confocal microscopy. Mitogen-activated protein kinase phosphorylation was revealed by Western immunoblotting. We showed that 1) microfilament disruption did not affect meiosis resumption and metaphase I meiotic apparatus formation but inhibited further cell cycle progression (chromosome separation) even though MAP kinase was phosphorylated; 2) cortical granule (CG) migration was driven by microfilaments (but not microtubules), and once the chromosomes and CGs were localized beneath the oolemma their anchorage to the cortex was independent of either microfilaments or microtubules; 3) neither microfilaments nor microtubules were involved in CG exocytosis during oocyte activation; 4) sperm incorporation was mediated by microfilaments, while pronuclear (PN) syngamy was controlled by microtubules rather than microfilaments; 5) spindle microtubule organization was temporally correlated with MAP kinase phosphorylation, while the extensive microtubule organization in the sperm aster that is required for PN apposition and syngamy occurred in the absence of MAP kinase activation; and 6) MAP kinase phosphorylation did not change either when microtubules were disrupted by nocodazole or when cytoplasmic microtubule asters were induced by taxol. The present study suggests that the role of the cytoskeleton during porcine oocyte maturation is similar to that of rodents, while the mechanisms of fertilization in pig resemble those of lower vertebrates.