White matter apoptosis is increased by delayed hypothermia and rewarming in a neonatal piglet model of hypoxic ischemic encephalopathy

Therapeutic hypothermia is widely used to treat neonatal hypoxic ischemic (HI) brain injuries. However, potentially deleterious effects of delaying the induction of hypothermia and of rewarming on white matter injury remain unclear. We used a piglet model of HI to assess the effects of delayed hypothermia and rewarming on white matter apoptosis. Piglets underwent HI injury or sham surgery followed by normothermic or hypothermic recovery at 2h. Hypothermic groups were divided into those with no rewarming, slow rewarming at 0.5°C/h, or rapid rewarming at 4°C/h. Apoptotic cells in the subcortical white matter of the motor gyrus, corpus callosum, lateral olfactory tract, and internal capsule at 29h were identified morphologically and counted by hematoxylin & eosin staining. Cell death was verified by terminal deoxynucleotidyl transferase (TdT) dUTP nick end labeling (TUNEL) assay. White matter neurons were also counted, and apoptotic cells were immunophenotyped with the oligodendrocyte marker 2',3'-cyclic-nucleotide 3'-phosphodiesterase (CNPase). Hypothermia, slow rewarming, and rapid rewarming increased apoptosis in the subcortical white matter relative to normothermia (p<0.05). The number of white matter neurons was not lower in groups with more apoptosis after hypothermia or rapid rewarming, indicating that the apoptosis occurred among glial cells. Hypothermic piglets had more apoptosis in the lateral olfactory tract than those that were rewarmed (p<0.05). The promotion of apoptosis by hypothermia and rewarming in these regions was independent of HI. In the corpus callosum, HI piglets had more apoptosis than shams after normothermia, slow rewarming, and rapid rewarming (p<0.05). Many apoptotic cells were myelinating oligodendrocytes identified by CNPase positivity. Our results indicate that delaying the induction of hypothermia and rewarming are associated with white matter apoptosis in a piglet model of HI; in some regions these temperature effects are independent of HI. Vulnerable cells include myelinating oligodendrocytes. This study identifies a deleterious effect of therapeutic hypothermia in the developing brain.

Change in Biotypic Diversity of Russian Wheat Aphid (Hemiptera: Aphididae) Populations in the United States

A key component of Russian wheat aphid, Diuraphis noxia (Kurdjumov), management has been through planting resistant wheat cultivars. A new biotype, RWA2, appeared in 2003 which caused widespread damage to wheat cultivars containing the Dn4 gene. Biotypic diversity in Russian wheat aphid populations has not been addressed since 2005 when RWA2 dominated the biotype complex. Our objectives were to determine the biotypic diversity in the Central Great Plains and Colorado Plateau at regional (2010, 2011, 2013) and local (2012) levels and detect the presence of new Russian wheat aphid biotypes. Regional and within-field aphid collections were screened against Russian wheat aphid-resistant wheat genotypes containing genes Dn3, Dn4, Dn6, Dn7, Dn9, CI2401; and resistant barley STARS 9301B. In 2010, all aphid collections from Texas were avirulent to the Dn4 resistance gene in wheat. Regional results revealed Dn4 avirulent RWA6 was widespread (55-84%) in populations infesting wheat in both regions. Biotypes RWA1, 2, and 3/7 were equally represented with percentages<20% each while RWA8 was rarely detected. Combining percentages of RWA1, 6, and 8 across regions to estimate avirulence to Dn4 gene revealed high percentages for both 2011 (64-80%) and 2013 (69-90%). In contrast, the biotype structure at the local level differed where biotype percentages varied up to ≥2-fold between fields. No new biotypes were detected; therefore, Dn7, CI2401, and STARS9301B remained resistant to all known Russian wheat aphid biotypes. This study documents a shift to Dn4 avirulent biotypes and serves as a valuable baseline for biotypic diversity in Russian wheat aphid populations prior to the deployment of new Russian wheat aphid-resistant wheat cultivars.

Boll weevil (Coleoptera: Curculionidae) response to and volatilization rates of grandlure when combined with varying doses of eugenol in the extended-life pheromone lure

Boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), trapping and pheromone quantitative analysis of extended-life pheromone lures manufactured with 0, 10, 20, and 30 mg of eugenol was conducted in the Rio Grande Valley of Texas under spring and summer conditions. Boll weevils responded positively to eugenol on one of 12 trapping weeks when densities were high, but when densities were low (<2 weevils trap(-1) wk(-1)), there were no significant differences in captures for any dosage of eugenol offered in a standard boll weevil trap. Weekly grandlure volatilization did not differ by eugenol dose but was significantly different when evaluated over three different trapping periods and by week within trapping period due to differences in ambient temperature. The amount of grandlure that remained after 4 wk in moderate temperatures of spring was 13.1 +/- 0.19 mg (55.7% of original 25 mg of content) compared with 5.5 +/- 0.15 mg remaining (22.8% of original 25 mg content) after for 4 wk in summer heat. Weekly volatilization of grandlure for the summer trapping period was 9.8 +/- 0.32 mg for the first week, declining steadily to 1.0 +/- 0.09 mg by the fourth week of age. The data indicate that at high summer temperatures >30 degrees C, accumulative grandlure loss per week may be too high, leaving too little residual grandlure to effectively attract boll weevils at the end of 3 wk of trapping. Eugenol plays no role in reserving or encouraging the release of grandlure, or in increasing boll weevil captures when boll weevil densities are low.

Comparisons of boll weevil (Coleoptera: Curculionidae) pheromone traps with and without kill strips

Boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), eradication programs typically equip pheromone traps with an insecticide-impregnated kill strip. These strips are intended to kill captured insects, thereby simplifying trap servicing and reducing the loss of weevils from predation and escape. However, the effectiveness of kill strips has not been extensively evaluated. We examined the influences of kill strips on weevil captures, trap servicing, and the incidences of weevil predation and trap obstruction (e.g., by spider webs). Evaluations were conducted weekly during three different production periods (pre- to early-, late-, and postseason) of cotton, Gossypium hirsutum L., to represent different environmental conditions and weevil population levels. Within each period, mean weekly captures of weevils in traps with and without kill strips were statistically similar. On average, traps with kill strips took 9 s longer to service than traps without kill strips, but statistical differences were only detected during the late-season period. Overall, the mean weekly proportion of traps with evidence of weevil predation or trap obstruction was significantly lower for traps with kill strips (0.25) than for traps without kill strips (0.37). However, this reduction in the frequency of weevil predation or trap obstruction was too small to produce a corresponding increase in the numbers of weevils captured. In light of these findings, the use of kill strips is likely unnecessary in eradication programs, but may be a consideration in situations when the numbers of deployed traps are reduced and chronic problems with weevil predation or trap obstruction exist.

Role of calcium and cyclophilin D in the regulation of mitochondrial permeabilization induced by glutathione depletion

The mitochondrial permeability transition (MPT) is a calcium and oxidative stress sensitive transition in the permeability of the mitochondrial inner membrane that plays a crucial role in cell death. However, the mechanism regulating the MPT remains controversial. To study the role of oxidative stress in the regulation of the MPT, we used diethyl maleate (DEM) to deplete glutathione (GSH) in human leukemic CEM cells. GSH depletion increased mitochondrial calcium and reactive oxygen species (ROS) levels in a co-dependent manner causing loss of mitochondrial membrane potential (deltapsi(m)) and cell death. These events were inhibited by the calcium chelator BAPTA-AM and the antioxidants N-acetylcysteine (NAC) and the triphenyl phosphonium-linked ubiquinone derivative MitoQ. In contrast, the MPT inhibitor cyclosporine A (CsA) and small interference RNA (siRNA) knockdown of cyclophilin D (Cyp-D) were not protective. These results indicate that mitochondrial permeabilization induced by GSH depletion is not regulated by the classical MPT.

Mitochondrial medicine: pharmacological targeting of mitochondria in disease

Mitochondria play a central role in cell life and death and are known to be important in a wide range of diseases including the cancer, diabetes, cardiovascular disease, and the age-related neurodegenerative diseases. The unique structural and functional characteristics of mitochondria enable the selective targeting of drugs designed to modulate the function of this organelle for therapeutic gain. This review discusses mitochondrial drug targeting strategies and a variety of novel mitochondrial drug targets including the electron transport chain, mitochondrial permeability transition, Bcl-2 family proteins and mitochondrial DNA. Mitochondrial drug-targeting strategies will open up avenues for manipulating mitochondrial functions and allow for selective protection or eradication of cells for therapeutic gain in a variety of diseases.

Reproductive potential of overwintering, F1, and F2 female boll weevils (Coleoptera: Curculionidae) in the Lower Rio Grande Valley of Texas

The feeding and oviposition activity of overwintering boll weevils, Anthonomus grandis grandis (Boheman), and seasonal fluctuations in development, survival, and reproduction of progeny of overwintering and first- and second-generation boll weevil females were determined in the laboratory at 27 degrees C, 65% RH, and a photoperiod of 12:12 (L:D) h. During the cotton-free period in the Lower Rio Grande Valley, female boll weevils without access to cotton resorb their unlaid eggs and enter reproductive diapause. However, when they were provided daily with greenhouse-grown cotton squares, commencement of oviposition began after 7, 15, or 20 d, depending on when they were captured. Females captured later in the winter fed longer before laying eggs than those captured in the early fall, suggesting that it may take females longer to terminate diapause the longer they have been dormant. The rate of feeding by females was significantly less during the winter months, and this may have affected the rate of diet-mediated termination of dormancy. Females of the first and second generations after the overwintering generation produced a significantly higher percentage of progeny surviving to adulthood and a higher proportion of these progeny were females. Offspring development time from overwintering female parents was significantly longer than that from first and second generations under the same laboratory conditions. The total number of lifetime eggs produced by females of the second generation during the cotton-growing season were approximately 9.9-fold higher than for overwintering females and 1.5-fold higher than for first-generation females. Life table calculations indicated that the population of second-generation boll weevils increased an average of 1.5-fold higher each generation than for females of the first generation and 22.6-fold higher than for overwintering females. Our data showed variation in boll weevil survival, development, and reproductive potential among the overwintering and first- and second-generation females, suggesting inherent seasonal fluctuations in these parameters.

Bax and the mitochondrial permeability transition cooperate in the release of cytochrome c during endoplasmic reticulum-stress-induced apoptosis

Endoplasmic reticulum (ER) stress induces apoptosis by mechanisms that are not fully clear. Here we show that ER stress induced by the Ca(2+)-ATPase inhibitor thapsigargin (THG) activates cytochrome c-dependent apoptosis through cooperation between Bax and the mitochondrial permeability transition (MPT) in human leukemic CEM cells. Pharmacological inhibition of the MPT as well as small interfering RNA (siRNA) knockdown of the MPT core component cyclophilin D blocked cytochrome c release and caspase-dependent apoptosis but did not prevent Bax activation, translocation or N-terminal exposure in mitochondria. siRNA knockdown of Bax also blocked THG-mediated cytochrome c release and apoptosis, but did not prevent MPT activation and resulted in caspase-independent cell death. Our results show that ER-stress-induced cell death involves a caspase and Bax-dependent pathway as well as a caspase-independent MPT-directed pathway.

The variable codons of H3 influenza A virus haemagglutinin genes

We have analyzed several sets of well-studied haemagglutinin (HA) gene sequences of H3 subtype influenza A viruses to identify codons that are unusually variable, using a simple pairwise sliding window method, DnDscanning. For two of the sets there were results of detailed phylogenetic modeling studies of selection already published. A third set had been the subject of an antigen mapping study, the results of which provide a completely independent benchmark of selected changes in H3 HA genes. Our analyses show that the codons with greatest DnDscan scores (i.e. the most variable) were mostly those reported in the published studies as being positively selected; indeed the DnDscan results matched the antigenic mapping results more closely than did those of the phylogenetic modeling methods. These results suggest that codons under selection can be found even when, as with some sets of virus sequences, a phylogeny is uncertain or cannot be obtained because, for example, the sequences are recombinants, or when selection is not necessarily linked with phylogeny, as in host-switching events. The program DnDscan is available at (biojanus.anu.edu.au).

Peroxynitrite-modified collagen-II induces p38/ERK and NF-kappaB-dependent synthesis of prostaglandin E2 and nitric oxide in chondrogenically differentiated mesenchymal progenitor cells

OBJECTIVE

Peroxynitrite (ONOO(-)) is formed in the inflamed and degenerating human joint. Peroxynitrite-modified collagen-II (PMC-II) was recently discovered in the serum of patients with osteoarthritis (OA) and rheumatoid arthritis (RA). Therefore we investigated the cellular effects of PMC-II on human mesenchymal progenitor cells (MPCs) as a model of cartilage and cartilage repair cells in the inflamed and degenerating joint.

DESIGN

MPCs were isolated from the trabecular bone of patients undergoing reconstructive surgery and were differentiated into a chondrogenic lineage. Cells were exposed to PMC-II and levels of the proinflammatory mediators nitric oxide (*NO) and prostaglandin E(2) (PGE(2)) measured. Levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2), phosphorylated mitogen activated protein kinases (MAPKs) and nuclear factor kappa B (NF-kappaB) activation were measured by enzyme linked immunosorbent assay (ELISA) together with specific MAPK and NF-kappaB inhibitors.

RESULTS

PMC-II induced ()NO and PGE(2) synthesis through upregulation of iNOS and COX-2 proteins. PMC-II also lead to the phosphorylation of MAPKs, extracellularly regulated kinase 1/2 (ERK1/2) and p38 [but not c-Jun NH(2)-terminal kinase (JNK1/2)] and the activation of proinflammatory transcription factor NF-kappaB. Inhibitors of p38, ERK1/2 and NF-kappaB prevented PMC-II induced ()NO and PGE(2) synthesis, iNOS and COX-2 protein expression and NF-kappaB activation.

CONCLUSION

iNOS, COX-2, NF-kappaB and MAPK are known to be activated in the joints of patients with OA and RA. PMC-II induced iNOS and COX-2 synthesis through p38, ERK1/2 and NF-kappaB dependent pathways suggesting a previously unidentified pathway for the synthesis of the proinflammatory mediators, ()NO and PGE(2), further suggesting that inhibitors of these pathways may be therapeutic in the inflamed and degenerating human joint.

Comparisons of standard and extended-life boll weevil (Coleoptera: Curculionidae) pheromone lures

The Southeastern Boll Weevil Eradication Program has proposed reducing maintenance program costs in eradicated zones by using an extended-life "superlure" in traps to detect populations of the boll weevil, Anthonomus grandis grandis Boheman. However, superlure effectiveness has not been extensively evaluated. We compared the superlure (30 mg of eugenol plus 25 mg of grandlure) to a standard lure (10 mg of grandlure) based on captures of weevils and changes in lure pheromone content. Lure treatments (standard and superlure, replaced biweekly or not replaced) were compared in 4-mo-long trapping periods. Captures of weevils did not generally reflect differences among lure treatments indicated by assays of lure contents. During the first 2 wk of exposure, amounts of pheromone released by the superlure were generally comparable with those of the standard lure, but pheromone composition was more stable. During the second 2 wk of exposure, the superlure usually released more pheromone than similarly aged standard lures, but less than half as much as the standard lure replaced biweekly. Based on numbers of captured weevils during the last 2 wk of an extended trapping period, the superlure performed similarly to the standard lure replaced biweekly. However, corresponding pheromone releases by the superlure were less than those by the standard lure replaced biweekly. This inconsistency suggests that numbers of captured weevils alone may be inadequate for evaluation of pheromone formulations. Our results suggest that better understanding of the consequences of reduced pheromone release during an extended trapping period is needed before adoption of the superlure can be recommended.

Squamous cell carcinoma arising in a tall cell papillary carcinoma of the thyroid

Transformation of differentiated thyroid cancer into poorly differentiated carcinoma is rare. This report describes a case in which preoperative fine needle aspiration suggested a squamous cell carcinoma whereas needle core biopsy favoured an undifferentiated carcinoma of probable thyroid origin. Histology of the subsequent total thyroidectomy specimen revealed a biphasic tumour comprising areas of tall cell papillary carcinoma merging with moderately to poorly differentiated squamous cell carcinoma. The immunohistochemical findings are discussed in detail.

Hydrogen sulfide protects colon cancer cells from chemopreventative agent β-phenylethyl isothiocyanate induced apoptosis

AIM: Hydrogen sulfide (H₂S) is a prominent gaseous constituent of the gastrointestinal (GI) tract with known cytotoxic properties. Endogenous concentrations of H₂S are reported to range between 0.2-3.4 mmol/L in the GI tract of mice and humans. Considering such high levels we speculate that, at non-toxic concentrations, H₂S may interact with chemical agents and alter the response of colonic epithelium cells to such compounds. The GI tract is a major site for the absorption of phytochemical constituents such as isothiocyanates, flavonoids, and carotenoids, with each group having a role in the prevention of human diseases such as colon cancer. The chemopreventative properties of the phytochemical agent β-phenyethyl isothiocyanate (PEITC) are well recognized. However, little is currently known about the physiological or biochemical factors present in the GI tract that may influence the biological properties of ITCs. The current study was undertaken to determine the effects of H₂S on PEITC mediated apoptosis in colon cancer cells.

METHODS: Induction of apoptosis by PEITC in human colon cancer HCT116 cells was assessed using classic apoptotic markers namely SubG1 population analysis, caspase-3 like activity and nuclear fragmentation and condensation coupled with the MTT [3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrasodium bromide] viability assay and LDH leakage.

RESULTS: PEITC significantly induced apoptosis in HCT116 cells as assessed by SubG1 population formation, nuclear condensation, LDH leakage and caspase-3 activity after 24 h, these data being significant from control groups (P < 0.01). In contrast, co-treatment of cells with physiological concentrations of H₂S (0.1-1 mmol/L) prevented PEITC mediated apoptosis as assessed using the parameters described.

CONCLUSION: PEITC effectively induced cell death in the human adenocarcinoma cell line HCT116 in vitro through classic apoptotic mechanisms. However, in the presence of H₂S, apoptosis was abolished. These data suggest that H₂S may play a significant role in the response of colonic epithelial cells to beneficial as well as toxic agents present within the GI tract.

A type of nucleotide motif that distinguishes tobamovirus species more efficiently than nucleotide signatures

The complete genomic sequences of forty-eight tobamoviruses were classified and found to form at least twelve species clusters. Individual species were not conveniently defined by 'nucleotide signatures' (i.e. strings of one or more nucleotides unique to a taxon) as these were scattered sparsely throughout the genomes and were mostly single nucleotides. By contrast all the species were concisely and uniquely distinguished by short nucleotide motifs consisting of conserved genus-specific sites intercalated with variable sites that provided species-specific combinations of nucleotides (nucleotide combination motifs; NC-motifs). We describe the procedure for finding NC-motifs in a convenient and phylogenetically conserved region of the tobamovirus RNA polymerase gene, the '4404-50 motif'. NC-motifs have been found in other sets of homologous sequences, and are convenient for use in published taxonomic descriptions.

The phylogeny of SARS coronavirus

Different tree-building methods consistently place the SARS corona-virus (SARS-CoV) as a basal Group 2 coronavirus rather than as an ungrouped species as concluded by others. Detailed comparisons of the SARS-CoV genomic sequence with those of six other coronaviruses failed to find evidence of recombination or genomic rearrangement using computational methods designed for that purpose.

Oat cover cropping and soil insecticides in an integrated sugarbeet root maggot (Diptera: Otitidae) management program

Sugarbeet, Beta vulgaris L., producers occasionally establish cereal cover crops to minimize early-season soil erosion, wind abrasion, and mechanical injury of seedlings. We evaluated the use of living oat, Avena sativa L., cover cropping as a cultural tactic to minimize feeding injury from sugarbeet root maggot, Tetanops myopaeformis (Röder), larvae at five field sites during 1996, 1998, and 1999. Sweep-net sampling yielded 4.8-, 11.2-, and 7.2-fold more flies from oat cover-cropped chlorpyrifos, terbufos, and untreated control plots, respectively, than in noncover counterparts. However, larval feeding injury in terbufos-treated plots was reduced when cover-cropped (383 seeds/m2) at St. Thomas in all years. A reduced oat seeding rate (224 seeds/m2) also enhanced root protection in terbufos-treated plots at St. Thomas in 1999. Less root injury was sustained in cover-cropped chlorpyrifos plots than in noncover counterparts at St. Thomas in 2 study yr. Oat cover cropping also frequently resulted in reduced T. myopaeformis feeding injury in the absence of a soil insecticide. Although trends toward increased yields were often evident, significant yield benefits were limited to a 6.8% root yield increase in oat cover plots when compared with noncover treatments overall at St. Thomas in 1996 and an 18.4% sucrose yield increase in terbufos-treated plots at St. Thomas in 1999. These findings suggest that beneficial interactions between planting-time soil insecticides and cereal cover crops are achievable in areas infested by T. myopaeformis. Demonstrated reductions in root feeding injury, combined with additional agronomic benefits, may warrant use of this production practice as part of an integrated management program for this key insect pest of sugarbeet.

Role of glutathione depletion and reactive oxygen species generation in apoptotic signaling in a human B lymphoma cell line

The primary objective of this study was to determine the sequence of biochemical signaling events that occur after modulation of the cellular redox state in the B cell lymphoma line, PW, with emphasis on the role of mitochondrial signaling. L-Buthionine sulphoximine (BSO), which inhibits gamma glutamyl cysteine synthetase (gammaGCS), was used to modulate the cellular redox status. The sequence and role of mitochondrial events and downstream apoptotic signals and mediators was studied. After BSO treatment, there was an early decline in cellular glutathione (GSH), followed by an increase in reactive oxygen species (ROS) production, which induced a variety of apoptotic signals (detectable at different time points) in the absence of any external apoptotic stimuli. The sequence of biochemical events accompanying apoptosis included a 95% decrease in total GSH and a partial (25%) preservation of mitochondrial GSH, without a significant increase in ROS production at 24h. Early activation and nuclear translocation of the nuclear factor kappa B subunit Rel A was observed at approximately 3h after BSO treatment. Cytochrome c release into the cytosol was also seen after 24h of BSO treatment. p53 protein expression was unchanged after redox modulation for up to 72 h, and p21waf1 independent loss of cellular proliferation was observed. Surprisingly, a truncated form of p53 was expressed in a time-dependent manner, beginning at 24h after BSO incubation. Irreversible commitment to apoptosis occurred between 48 and 72 h after BSO treatment when mitochondrial GSH was depleted, and there was an increase in ROS production. Procaspase 3 protein levels showed a time-dependent reduction following incubation with BSO, notably after 48 h, that corresponded with increasing ROS levels. At 96 h, caspase 3 cleavage products were detectable. The pan-caspase inhibitor zVADfmk, partially blocked the induction of apoptosis at 48 h, and was ineffective after 72 h. PW cells could be rescued from apoptosis by removing them from BSO after up to 48, but not 72 h incubation with BSO. Mitochondrial transmembrane potential (DeltaPsi(m)) remained intact in most of the cells during the 72 h observation period, indicating that DeltaPsi(m) dissipation is not an early signal for the induction of redox dependent apoptosis in PW cells. These data suggest that a decrease in GSH alone can act as a potent early activator of apoptotic signaling. Increased ROS production following mitochondrial GSH depletion, represents a crucial event, which irreversibly commits PW cells to apoptosis.

The haemagglutinin gene, but not the neuraminidase gene, of 'Spanish flu' was a recombinant

Published analyses of the sequences of three genes from the 1918 Spanish influenza virus have cast doubt on the theory that it came from birds immediately before the pandemic. They showed that the virus was of the H1N1 subtype lineage but more closely related to mammal-infecting strains than any known bird-infecting strain. They provided no evidence that the virus originated by gene reassortment nor that the virus was the direct ancestor of the two lineages of H1N1 viruses currently found in mammals; one that mostly infects human beings, the other pigs. The unusual virulence of the virus and why it produced a pandemic have remained unsolved. We have reanalysed the sequences of the three 1918 genes and found conflicting patterns of relatedness in all three. Various tests showed that the patterns in its haemagglutinin (HA) gene were produced by true recombination between two different parental HA H1 subtype genes, but that the conflicting patterns in its neuraminidase and non-structural-nuclear export proteins genes resulted from selection. The recombination event that produced the 1918 HA gene probably coincided with the start of the pandemic, and may have triggered it.

Rotenone-induced G2/M cell cycle arrest and apoptosis in a human B lymphoma cell line PW

Concentrations of rotenone (ROT) that block electron flow through mitochondrial complex I (100 nM) did not significantly alter either cell viability or the growth of PW cells. However, 10- to 50-fold higher concentrations (1-5 microM) were found to induce a dose-dependent cell cycle arrest predominantly at the G2/M stage of the cycle and apoptosis. Apoptosis was dependent on the cell cycle arrest, since apoptosis but not the G2/M arrest was prevented with the broad spectrum caspase inhibitor zVADfmk. Biochemical features of apoptosis included mitochondrial cytochrome c release, reactive oxygen species generation, and the activation of procaspase 3. Thus, ROT inhibition of mitochondrial electron transport may be insufficient to induce apoptosis in PW cells. Instead, apoptosis in these cells occurs as a consequence of disruption of the cell cycle and is only indirectly dependent upon mitochondrial electron transport.

Recombination in the hemagglutinin gene of the 1918 "Spanish flu"

When gene sequences from the influenza virus that caused the 1918 pandemic were first compared with those of related viruses, they yielded few clues about its origins and virulence. Our reanalysis indicates that the hemagglutinin gene, a key virulence determinant, originated by recombination. The "globular domain" of the 1918 hemagglutinin protein was encoded by a part of a gene derived from a swine-lineage influenza, whereas the "stalk" was encoded by parts derived from a human-lineage influenza. Phylogenetic analyses showed that this recombination, which probably changed the virulence of the virus, occurred at the start of, or immediately before, the pandemic and thus may have triggered it.

Bcl-2 inhibits apoptosis induced by mitochondrial uncoupling but does not prevent mitochondrial transmembrane depolarization

Bcl-2 overexpression protects cells from apoptosis induced by many cytotoxic agents. In this study, we investigated the effects of uncoupling mitochondrial electron transport in both HL60 wild-type and Bcl-2-overexpressing cells using the protonophore carbonyl cyanide m-chlorophenylhydrazone. We found that uncoupling mitochondrial electron transport induced apoptosis in wild-type, but not in Bcl-2-overexpressing cells. To investigate the mechanism of action of Bcl-2-mediated inhibition of cyanide m-chlorophenylhydrazone-induced apoptosis, we measured the mitochondrial transmembrane potential (DeltaPsi(m)) after uncoupling mitochondrial electron transport and found that both HL-60 wild-type and Bcl-2-overexpressing cells similarly depolarize following cyanide m-chlorophenylhydrazone exposure. Western blot analysis demonstrated that Bcl-2 overexpression did not completely block cytochrome c release from mitochondria after uncoupling mitochondrial electron transport. Since Bcl-2 may act as an antioxidant, we studied the effect of altering the cellular redox state prior to uncoupling mitochondrial electron transport in Bcl-2-overexpressing cells. Depletion of mitochondrial (but not cytosolic) glutathione induced apoptosis in Bcl-2-overexpressing cells and negated the protective effect of Bcl-2. Furthermore, following glutathione depletion, Bcl-2-overexpressing cells were sensitized to undergo cyanide m-chlorophenylhydrazone-induced apoptosis. These data suggest that the action of Bcl-2 is dependent, in part, on the cellular and mitochondrial redox state.

Haplotype and AGG-interspersion analysis of FMR1 (CGG)(n) alleles in the Danish population: implications for multiple mutational pathways towards fragile X alleles

The AGG interspersion pattern and flanking microsatellite markers and their association with instability of the FMR1 (CGG)(n) repeat, involved in the fragile X syndrome, were analyzed in DNA from filter-paper blood spots randomly collected from the Danish newborn population. Comparison of DXS548-FRAXAC1 haplotype frequencies in the normal population and among fragile X patients suggested strong linkage disequilibrium between normal alleles and haplotype 7-3 and between fragile X alleles and haplotype 2-1 and 6-4. Comparison of the AGG interspersion pattern in 143 alleles, ranging in size from 34-62 CGG, and their associated haplotypes indicates the existence of at least three mutational pathways from normal alleles toward fragile X alleles in the Danish population. Two subgroups of normal alleles, with internal sequences of (CGG)(10)AGG(CGG)(19) and (CGG)(9)AGG(CGG)(12) AGG(CGG)(9), possibly predisposed for expansion, were identified in the data set. When alleles larger than 34 CGG were investigated, comparing the length of 3' uninterrupted CGG triplets (uCGG), we found that alleles associated with haplotype 2-1 and 6-4 contain significantly longer stretches of uCGG than alleles associated with haplotype 7-3. Thus, the data support that (CGG)(n) instability is correlated to the length of uCGG.

Sister-scanning: a Monte Carlo procedure for assessing signals in recombinant sequences

MOTIVATION

To devise a method that, unlike available methods, directly measures variations in phylogenetic signals in gene sequences that result from recombination, tests the significance of the signal variations and distinguishes misleading signals.

RESULTS

We have developed a method, that we call 'sister-scanning', for assessing phylogenetic and compositional signals in the various patterns of identity that occur between four nucleotide sequences. A Monte Carlo randomization is done for all columns (positions) within a window and Z-scores are obtained for four real sequences or three real sequences with an outlier that is also randomized. The usefulness of the approach is demonstrated using tobamovirus and luteovirus sequences. Contradictory phylogenetic signals were distinguished in both datasets, as were regions of sequence that contained no clear signal or potentially misleading signals related to compositional similarities. In the tobamovirus dataset, contradictory phylogenetic signals were separated by coding sequences up to a kilobase long that contained no clear signal. Our re-analysis of this dataset using sister-scanning also yielded the first evidence known to us of an inter-species recombination site within a viral RNA-dependent RNA polymerase gene together with evidence of an unusual pattern of conservation in the three codon positions.

Analysis of FMR1 (CGG)n alleles and FRAXA microsatellite haplotypes in the population of Greenland: implications for the population of the New World from Asia

The fragile X syndrome is caused by the expansion of a polymorphic (CGG)n tract in the promoter region of the FMR1 gene. Apparently the incidence of fragile X syndrome is rare in the population of Greenland. In order to examine population-related factors involved in stability of the (CGG)n sequence, DNA samples obtained randomly from the Greenlandic population were analysed for size and AGG interspersion pattern of the FMR1 (CGG)n region and associated DXS548-FRAXAC1 haplotypes. In addition a large Greenland family with unstable transmission in the premutation range was analysed. The (CGG)n allele sizes in the Greenland population showed a narrow distribution similar to that reported for Asian populations. DNA sequencing of alleles with 36 CGG repeats revealed an AGG(CGG)6 insertion previously reported exclusively in Asian populations and a high frequency of alleles with a (CGG)10AGG(CGG)9AGG(CGG)9 or (CGG)9AGG(CGG)9AGG(CGG)6AGG(CGG)9 sequence pattern was found. Thus the data confirm the Asian origin of the Greenlandic (Eskimo) population and indicates that some (CGG)n alleles have remained stable for 15-30,000 years, since the population of the New World arrived from Asia via the Bering Strait.

Characterization of reactive oxygen species induced effects on human spermatozoa movement and energy metabolism

Reactive oxygen species (ROS) inhibit sperm movement and have been implicated in male infertility. In this study, we determined the effects of specific ROS produced by activated leukocytes on human spermatozoa and investigated their metabolic site of action. We used chemiluminescence and electron paramagnetic resonance (EPR) to characterize the ROS generated by both blood and seminal leukocytes. We also determined the effects of these ROS on sperm energy metabolism using biochemical analyses and flow cytometry. Both blood and seminal leukocytes produced the same characteristic ROS which were determined to be hydrogen peroxide (H2O2) and superoxide radicals (O2*-). EPR using the spin trapping technique indicated that superoxide radical-dependent hydroxyl radicals (HO.) were also generated. ROS generated by PMA-stimulated blood leukocytes (2-5 x 10(6)/ml) caused inhibition of sperm movement in 2 h (p < .01). Using the hypoxanthine/ xanthine oxidase (0.5 U/ml) system to generate ROS, we determined that spermatozoa ATP levels, after ROS treatment, were reduced approximately eight-fold in 30 min (0.10 x 10(10) moles/10(6) sperm cells) compared to control (0.84 X 10(-10) moles/10(6) sperm cells) (p < .01). Sperm ATP reduction paralleled the inhibition of sperm forward progression. Neither superoxide dismutase (100 U/ml) nor dimethyl sulfoxide (100 mM) reversed these effects; however, protection was observed with catalase (4 X 10(3) U/ml). Flow cytometric analyses of sperm treated with various doses of H2O2 (0.3 mM-20.0 mM) showed a dose-dependent decrease in sperm mitochondrial membrane potential (MMP); however, at low concentrations of H2O2, sperm MMP was not significantly inhibited. Also, sperm MMP uncoupling with CCClP had no effect on either sperm ATP levels or forward progression. These results indicate that H2O2 is the toxic ROS produced by activated leukocytes causing the inhibition of both sperm movement and ATP production. O2*- and HO. do not play a significant role in these processes. Low concentrations of H2O2 causing complete inhibition of sperm movement and ATP levels inhibit sperm energy metabolism at a site independent of mitochondrial oxidative phosphorylation.

Decreased levels of interleukin-12 are not correlated with leukocyte concentration and superoxide dismutase activity in semen of infertile men

The interleukin (IL)-12 levels and the superoxide dismutase (SOD) activity were determined in the seminal plasma of fertile and infertile men with or without leukocytospermia by ELISA. The IL-12 levels differed significantly among the fertile and infertile groups, with the infertile groups showing lower levels that were not modulated by leukocytospermia. The SOD activity did not differ significantly among the fertile and infertile groups and was not correlated with the IL-12 levels. The positive correlation with sperm concentration suggests that IL-12 may have a direct or indirect role in male fertility/infertility and that its levels are not modulated by the presence of leukocytes in the semen.

Antioxidant potential of human serum albumin: role in the recovery of high quality human spermatozoa for assisted reproductive technology

Human serum albumin (HSA) is being considered as an alternate media for sperm enrichment in assisted reproductive technology (ART) because of recent concern with the use of Percoll. In this study, we compared HSA and Percoll for 1) sperm recovery, 2) reactive oxygen species scavenging potential, and 3) effects on total oxidative stress to spermatozoa. The spermatozoa-enriched fractions obtained from Percoll (80%:40%) and HSA (12%) were monitored for sperm motility, viability, hypoosmotic swelling test (HOST), and adenosine triphosphate (ATP) levels. The effect of superoxide anions (O2.-) on donor human spermatozoa was observed in the presence of either HSA or Percoll media. A combination of luminol and the Cypridina luciferin analog 2-methyl-6-(4-methoxyphenyl)-3,7-dihydroimidazo(1,2-alpha)pyraz in-3-one hydrochloride was used as a highly sensitive chemiluminescence probe in our hypoxanthine and xanthine oxidase-based assay for O2.-. Sperm membrane total oxidative stress was determined by measuring levels of the prostanoid 8-iso-Prostaglandin F2alpha (8-iso-PGF2alpha). Significant differences in sperm parameters between the Percoll-enriched spermatozoa (motility 60%+/-4%, viability 56%+/-6%, and HOST 73%+/-7%) and those enriched with HSA (motility 84%+/-5%, viability 85%+/-4%, and HOST 84%+/-3%; P < 0.01) were observed. Adenosine triphosphate levels were significantly higher, by almost 50%, in samples processed with HSA than with Percoll (P=0.03). The dismutation rate of O2.- in HSA (slope -6.8) was significantly lower than in Percoll (slope -87.0; P < 0.01). Sperm motility and ATP levels decreased at a slower rate after treatment with O2.- in the presence of HSA when compared to Percoll; moreover, spermatozoa in HSA regained partial motility after 2 hours, whereas spermatozoa in Percoll were immobilized. No significant differences in 8-iso-PGF2alpha levels in spermatozoa enriched by either HSA or Percoll were observed. We conclude that the HSA sperm enrichment procedure improves the recovery of higher quality spermatozoa compared to Percoll and, because of its antioxidant properties, may be useful in processing high leukospermia semen samples for ART purposes.

Hepatotoxicity and accelerated fibrosis following 3,4-methylenedioxymetamphetamine ("ecstasy") usage

3,4-Methylenedioxymetamphetamine ("ecstasy") has previously been reported to cause an acute hepatitis that may progress to liver failure. We present the first recorded case of ecstasy-induced accelerated hepatic fibrosis.

Differences in human immunodeficiency virus type 1 V3 sequences from patients with and without AIDS dementia complex

Paired serum and cerebrospinal fluid (CSF) samples from 10 AIDS patients with and 10 without AIDS dementia complex (ADC) were studied, in an attempt to uncover ADC-associated variation in V3 sequences. Sequences were obtained from four of the patients with and eight of those without ADC. Comparison of the sequences using a resampling technique revealed a significant ADC-associated difference occurring at several amino acid positions. Results from serum and CSF sequences were comparable. These differences may indicate that the virus found in ADC and that in non-ADC patients have different biological properties. Comparison of serum versus CSF sequences within samples from both ADC and non-ADC patients, using the same resampling technique, revealed no clear distinctions. In some patients, the sequence populations in serum and CSF were completely distinct, while in others, there was no difference in distribution. These patterns were not associated with ADC.

Hamartomas of the breast: six novel diagnostic features in three-dimensional thick sections

Fifteen hamartomas of the breast have been studied by dissecting microscopy of thick sections at a depth of 1.0 to 2.5 mm, and by conventional 5 microns deep sections. This combined approach has revealed six distinctive features, three in the parenchymal structure and three in the connective tissue components. Ducts (invariably of penetrating or arcuate configuration) and discrete lobules, neither of which are seen in lesions accepted as fibroadenomas, were invariably found. In one-third of hamartomas, up to 10% of the surface area was occupied by Herãti-style nodules composed of concentric rings of epithelium. In the hyaline interlobular connective tissue characteristic drifts of caraway seed-like fibrocytes, encasement of adipocytes by hyaline collagen, or spider-naevus vascular abnormalities were found in approximately half of the mammary hamartomas when examined in thick sections. Hitherto the positive diagnosis of hamartomas of the breast has relied on a combined clinical, radiological and pathological assessment. We suggest that the additional features described here, taken in conjunction with those already known, may facilitate the recognition of mammary hamartomas by histopathological examination alone.

SIMPLE34: an improved and enhanced implementation for VAX and Sun computers of the SIMPLE algorithm for analysis of clustered repetitive motifs in nucleotide sequences

SIMPLE34 is an improved and enhanced version of SIMPLE for Vax and SunOS systems. It now provides a length-independent measure of the overall level of tri- and tetranucleotide motif clustering within nucleotide sequences and its significant deviation from random expectation. It now also provides information on tri- and tetranucleotide motifs showing higher levels of clustering than would be expected in random sequences. Sequence simplicity of test sequences can be judged with respect to random sequences generated on the basis of base composition, positional base composition or doublet frequency. These options can be used to investigate factors resulting in sequence simplicity.

Non-nuclear staining of thick tissue sections

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Will screening for breast cancer reduce mortality? Evidence from the first year of screening in Avon

In the first year of screening in Avon, 93 malignant lesions were detected of which one-half were impalpable. Of the impalpable lesions, one-half were in situ or showed areas of microinvasion only. One-fifth of the malignant lesions were invasive tumours of special histological type which are known to carry a good prognosis even when not detected by screening. One-quarter of the lesions had clinical or pathological features which would be expected to confer a poor prognosis. Only 16 invasive ductal carcinomas measuring 1 cm or less in diameter were detected--a small proportion of the total number of malignant lesions. Although these early figures suggest that the effect of screening on mortality from breast cancer may be small, continued high-quality screening and careful detailed analysis are essential to determine the effect of screening on the mortality from breast cancer and the effect on the population as a whole.

Backprocessing paraffin wax blocks for subgross examination

A method called "backprocessing", for subgross examination of sections, ranging between 50 microns and 1 mm in thickness using a dissecting microscope was developed. It requires either archival or current diagnostic breast tissue. In this study tissue is assumed to have been already embedded in paraffin wax for immediate diagnostic purposes. The advantages of backprocessing include the ability to select valuable or rare diagnostic tissue from archival histopathological material, and the preservation of histological structure should further examination at 5 microns thickness be required at a later date.

Diagnostic and therapeutic aspects of fine-wire localization biopsy for impalpable breast cancer

During the first 2 years (July 1989 to July 1991) of the Avon Breast Screening Service, fine-wire localization biopsy was indicated in 213 impalpable breast lesions. A total of 144 lesions were benign and 69 malignant. Only four of 213 lesions (1.9 per cent) were not excised at the first localization. Factors influencing reoperation in the 69 patients with malignant impalpable lesions were examined. There was a significant association (P < 0.001) between parenchymal disturbances on mammography and invasive carcinoma, and between non-invasive carcinoma and microcalcification (P < 0.001). In 31 patients the localization biopsy was the only surgical procedure. Thirty-eight patients required further surgery: 12 underwent further local excision and 26 mastectomy. Reoperation was more frequent in patients with calcification than in those with parenchymal disturbance (P < 0.001). The most frequent indications for mastectomy were inadequate excision of widespread comedo ductal carcinoma in situ or invasive ductal carcinoma combined with extensive ductal carcinoma in situ. Fine-wire localization biopsy was a combined therapeutic and diagnostic procedure in 31 of 69 women with impalpable screen-detected lesions. The majority of patients required further surgery because radiological abnormalities underestimated the extent of disease.

Chronochemistry, rubber, and formalin

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Laboratory handling of impalpable breast lesions: a review

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Differential marking of excision planes in screened breast lesions by organically coloured gelatins

Traditionally India ink has been used to mark surgical resection margins, more recently with acetone to aid drying. Alternative methods have been suggested in recent months, including solutions of alcian blue, and Tippex. These methods use one colour only and Tippex is radiodense. Artists' pigments have been used, but their radiodensity makes them unsuitable for the detailed mammograms of the sliced screened specimens. An alternative method was specifically designed for impalpable breast lesions. It is based on coloured gelatins that are painted on to the biopsy specimen before dissection. The markers are radiolucent, quick to set, and do not penetrate the connective tissue. They can be applied to both fresh and fixed tissues, and the cost is about 0.05 pounds a specimen. The system is also suitable for marking other large specimens.