Studies on dicistronic polioviruses implicate viral proteinase 2Apro in RNA replication

A dicistronic poliovirus W1-P1/E/P2,3-1 with the genotype [PV]5'NTR-P1-[EMCV]IRES-[PV]P2,3-3'NTR (Molla, Jang, Paul, Reuer, and Wimmer, 1992, Nature 356, 255) was used to investigate whether the viral proteinase 2Apro, whose primary function in proteolytic processing was erased through the insertion of an internal ribosomal entry site (IRES) element into the ORF of the polyprotein, had other function(s) in viral replication. Deletion of 2Apro from W1-P1/E/P2,3-1 rendered the corresponding transcripts unable to replicate whereas partial deletion of 2Apro or an exchange of Cys109 (an amino acid of the catalytic triad of the proteinase) to Ala reduced RNA replication. No cytopathic effects were observed after transfection with any of the three dicistronic constructs containing mutant 2A, and no virus was recovered after attempts to expand a possibly low yield of mutant virus. In contrast, insertion of the IRES of encephalomyocarditis virus (EMCV) into the ORF of the poliovirus polyprotein at the cleavage site between 2Apro and 2B yielded the novel dicistronic virus W1-P1,2A/E/2BC,P3-1 with the genotype [PV]5'NTR-P1-2A-[EMCV]IRES-[PV]2BC-P3-3'NTR, expressing a small plaque phenotype. These results indicate that neither the intact P2 polypeptide nor the cleavage fragment 2AB of P2 is required for viral proliferation. On the other hand, 2Apro appears to be an essential component in RNA replication as no viral RNA synthesis can be observed by reverse transcription/PCR in cells transfected with dicistronic RNA lacking this viral polypeptide.

Amplification of a long terminal repeat-like element on the Y chromosome of the platyfish, Xiphophorus maculatus

The platyfish (Xiphophorus maculatus), in which sex chromosomes are evident from stable and predictable inheritance of sex, is one of the best-studied lower vertebrates with respect to sex determination. In order to identify the structural equivalent for this in the karyotype, which does not contain heteromorphic pairs of chromosomes, two sex-linked molecular probes were used for fluorescent in situ hybridization analysis. One probe, derived from the melanoma oncogene locus ONC-Xmrk, stained both the X and the Y chromosome. This cytogenetic analysis mapped the sex-determining locus to the subtelomeric region of a medium-sized telocentric chromosome. Another probe, a repetitive element (XIR), specifically labeled the Y chromosome in metaphase spreads and in interphase nuclei. The sex chromosomes of X. maculatus can be considered to be at an early stage of evolution of gonosomes. Expansion of the XIR repeat is obviously one of the earliest of the molecular events that lead to divergence of the Y chromosome and recombinational isolation of the sex-determining locus.

Early stages of sex chromosome differentiation in fish as analysed by simple repetitive DNA sequences

Animal sex chromosome evolution has started on different occasions with a homologous pair of autosomes leading to morphologically differentiated gonosomes. In contrast to other vertebrate classes, among fishes cytologically demonstrable sex chromosomes are rare. In reptiles, certain motifs of simple tandemly repeated DNA sequences like (gata)n/(gaca)m are associated with the constitutive heterochromatin of sex chromosomes. In this study a panel of simple repetitive sequence probes was hybridized to restriction enzyme digested genomic DNA of poeciliid fishes. Apparent male heterogamety previously established by genetic experiments in Poecilia reticulata (guppy) was correlated with male-specific hybridization using the (GACA)4 probe. The (GATA)4 oligonucleotide identifies certain male guppies by a Y chromosomal polymorphism in the outbred population. In contrast none of the genetically defined heterogametic situations in Xiphophorus could be verified consistently using the collection of simple repetitive sequence probes. Only individuals from particular populations produced sex-specific patterns of hybridization with (GATA)4. Additional poeciliid species (P. sphenops, P. velifera) harbour different sex-specifically organized simple repeat motifs. The observed sex-specific hybridization patterns were substantiated by banding analyses of the karyotypes and by in situ hybridization using the (GACA)4 probe.

Activation of nuclear factor-kB in the spinal cord of experimental allergic encephalomyelitis

The DNA-binding activity of nuclear factor (NF-kB) was found to be induced in the spinal cord of rats with experimental allergic encephalomyelitis (EAE), an animal model of multiple sclerosis (MS), from the onset of the disease. This activation of NF-kB persisted throughout the disease period and decreased thereafter in the recovery phase. Supershift analysis of NF-kB DNA-binding activity in nuclear extracts of spinal cords showed that RelA/p65 and p50 subunits but not c-Rel/p75, RelB/p68 and p52 subunits were involved in DNA binding. Pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-kB activation, markedly inhibited the in vivo activation of NF-kB in the spinal cord of EAE rats and attenuated the clinical symptoms of EAE. These studies suggest that activation of NF-kB plays an important role in the pathogenesis of EAE and inhibitors of NF-kB activation may have therapeutic importance in MS.

Association between fetal fraction on cell-free DNA testing and first-trimester markers for pre-eclampsia

OBJECTIVES

To evaluate the association between fetal fraction on cell-free DNA (cfDNA) testing and first-trimester markers for pre-eclampsia, and to investigate the possible association of low fetal fraction with increased risks for pre-eclampsia (PE) and fetal growth restriction (FGR).

METHODS

This was a retrospective cohort study including all women with a singleton pregnancy who had risk calculation for PE and FGR between 11 + 0 and 13 + 6 weeks' gestation and who also had cfDNA as a primary or secondary screening test for chromosomal abnormalities at any gestational age at two fetal medicine clinics in Sydney and Melbourne, Australia, between March 2013 and May 2017. Logarithmically transformed fetal fraction results were adjusted for gestational age and maternal characteristics. Associations with mean arterial pressure (MAP), mean uterine artery pulsatility index (UtA-PI), pregnancy-associated plasma protein A (PAPP-A), placental growth factor (PlGF), and risks for PE < 34 weeks, PE < 37 weeks and FGR < 37 weeks were analyzed using correlation analysis and univariable and multivariable linear regressions.

RESULTS

In total, 4317 singleton pregnancies that underwent cfDNA testing with fetal fraction reported were included. Significant prediction of fetal fraction was provided by gestational age, conception by in-vitro fertilization, maternal age, body mass index, chronic hypertension, diabetes mellitus, South Asian ethnicity and being parous without history of PE or FGR. Fetal fraction was associated inversely with MAP and UtA-PI and associated positively with PAPP-A and PlGF. The lower the fetal fraction, the higher were the risks for PE < 34 weeks, PE < 37 weeks and FGR < 37 weeks (P < 0.001 for all).

CONCLUSIONS

There is a significant association between fetal fraction result and first-trimester markers for adverse pregnancy outcome. Low fetal fraction is associated with an increased risk for pregnancy complication, but its capacity to act an as independent first-trimester marker in an algorithm for screening for PE and FGR requires further research. Copyright © 2017 ISUOG. Published by John Wiley & Sons Ltd.

Coupling mechanism of the oxaloacetate decarboxylase Na(+) pump

The oxaloacetate decarboxylase Na(+) pump consists of subunits alpha, beta and gamma, and contains biotin as the prosthetic group. The peripheral alpha subunit catalyzes the carboxyltransfer from oxaloacetate to the prosthetic biotin group to yield the carboxybiotin enzyme. Subsequently, this is decarboxylated in a Na(+)-dependent reaction by the membrane-bound beta subunit. The decarboxylation is coupled to Na(+) translocation from the cytoplasm into the periplasm, and consumes a periplasmically derived proton. The gamma subunit contains a Zn(2+) metal ion which may be involved in the carboxyltransfer reaction. It is proposed to insert with its N-terminal alpha-helix into the membrane and to form a complex with the alpha subunit with its water-soluble C-terminal domain. The beta subunit consists of nine transmembrane alpha-helices, a segment (IIIa) which inserts from the periplasm into the membrane but does not penetrate it, and connecting hydrophilic loops. The most highly conserved regions of the molecule are segment IIIa and transmembrane helix VIII. Functionally important residues are D203 (segment IIIa), Y229 (helix IV) and N373, G377, S382 and R389 (helix VIII). The polar of these amino acids may constitute a network of ionizable groups which promotes the translocation of Na(+) and the oppositely oriented translocation of H(+) across the membrane. Evidence indicates that two Na(+) ions are bound simultaneously to subunit beta with D203 and S382 acting as binding sites. Sodium ion binding from the cytoplasm to both sites elicits decarboxylation of carboxybiotin possibly with the consumption of the proton extracted from S382 and delivered via Y229 to the carboxylated prosthetic group. A conformational change exposes the bound Na(+) ions toward the periplasm. With H(+) entering from the periplasm, the hydroxyl group of S382 is regenerated, and as a consequence, the Na(+) ions are released into this compartment. After switching back to the original conformation, Na(+) pumping continues.

Anti-inflammatory activity of hamamelis distillate applied topically to the skin. Influence of vehicle and dose

The anti-inflammatory activity of hamamelis distillate has been evaluated with respect to drug concentration (0.64 mg/2.56 mg hamamelis ketone/100 g) and the effect of the vehicle (O/W emulsion with/without phosphatidylcholine (PC) in an experimental study. The effects were compared with those of chamomile cream, hydrocortisone 1% cream and 4 base preparations. Erythema was induced by UV irradiation and cellophane tape stripping of the horny layer in 24 healthy subjects per test. Skin blanching was quantified by visual scoring and chromametry. Drug effects were compared with one another and with an untreated control area, as well as with any action due to the vehicle. UV-induced erythema at 24 h was suppressed by low dose hamamelis PC-cream and hydrocortisone cream. Hydrocortisone appeared superior to both hamamelis vehicles, hamamelis cream (without PC) and chamomile cream. The latter preparation was also less potent than hamamelis PC-cream. Erythema 4 to 8 h after the stripping of the horny layer was suppressed by hydrocortisone (P < or = 0.05). Inflammation was also less pronounced following low dose hamamelis PC-cream and chamomile cream. Hamamelis PC-cream, however, appeared less potent than hydrocortisone. In general, visual scoring was more discriminatory than chromametry. The results have demonstrated an anti-inflammatory activity of hamamelis distillate in a PC-containing vehicle. A fourfold increase of drug concentration, however, did not produce an increase in activity.

The sensitivity of posturographic parameters to acquisition settings

The objective of this study was to evaluate the sensitivity of posturographic parameters (PP) to changes in acquisition settings. A group of eight young adults underwent a set of typical orthostatic posture trials, and selected PP were then calculated from a set of centre of pressure (CoP) displacement time series obtained by applying different cut-off frequencies to the same set of raw data. Four PP out of 11 showed significant changes with respect to cut-off frequency. Statistical mechanics parameters exhibited smaller sensitivity than summary measures. On the basis of the results obtained, a proposal for a standard cut-off frequency and a sampling rate value is embodied in the paper together with some suggestions on measurement settings, with a view to standardized use of instrumentation for quantitative analysis in orthostatic posturography.

Structure of Ag(111)-p(4 x 4)-O: no silver oxide

The structure of the oxygen-induced p(4 x 4) reconstruction of Ag(111) is determined by a combination of scanning tunneling microscopy, surface x-ray diffraction, core level spectroscopy, and density functional theory. We demonstrate that all previous models of this surface structure are incorrect and propose a new model which is able to explain all our experimental findings but has no resemblance to bulk silver oxide. We also shed some light on the limitations of current density functional theories and the potential role of van der Waals interactions in the stabilization of oxygen-induced surface reconstructions of noble metals.

Hemodynamics as a possible internal mechanical disturbance to balance

The postural control system is assessed by observing body sway while the subject involved aims at maintaining a specified up-right posture. Internal masses generate internal reaction forces that constitute an internal mechanical stimulus that may contribute to cause segmental displacements, i.e. body sway. Thus, gaining knowledge about the amplitude and direction of these reaction forces would contribute to gain insights into the mechanisms that influence the maintenance of balance and into its control. The 3-D force vector that acts on the body centre of mass (COM) and is associated with the transient blood movement at each cardiac cycle was assessed in a population sample of 20 young adults during the maintenance of a quiet up-right posture. Typical patterns of the three components of this force vector were identified. Relevant parameters were selected and submitted to sample statistics. For a number of them, linear correlation with subject-specific parameters was found. The antero-posterior force component was characterised by a triphasic major wave, the peaks of which had values up to 0.40 N. The vertical component showed a repeatable triphasic wave with peak-to-peak values in the range 1.3-3.0 N. The medio-lateral component showed relatively low peak-to-peak values (in the range 0.05-0.10 N). The resultant vector had an amplitude that underwent several oscillations during the cardiac cycle and reached its maximal value in the range 0.6-1.7 N.

The two human organic cation transporter genes SLC22A1 and SLC22A2 are located on chromosome 6q26

Polyspecific transporters for organic cations (OCT) belong to a new protein family which also include organic anion transporters. The first human transporters from this family (OCT1, OCT2) have been recently cloned. They translocate small cations like tetraethylammonium, choline and monoamine neurotransmitters and are involved in hepatic and renal cation excretion, respectively. We have localized the OCT1 and OCT2 genes (SLC22A1, SLC22A2) on chromosome 6q26.

The importance of knowing when to stop. A sequential stopping rule for component-wise gradient boosting

OBJECTIVES

Component-wise boosting algorithms have evolved into a popular estimation scheme in biomedical regression settings. The iteration number of these algorithms is the most important tuning parameter to optimize their performance. To date, no fully automated strategy for determining the optimal stopping iteration of boosting algorithms has been proposed.

METHODS

We propose a fully data-driven sequential stopping rule for boosting algorithms. It combines resampling methods with a modified version of an earlier stopping approach that depends on AIC-based information criteria. The new "subsampling after AIC" stopping rule is applied to component-wise gradient boosting algorithms.

RESULTS

The newly developed sequential stopping rule outperformed earlier approaches if applied to both simulated and real data. Specifically, it improved purely AIC-based methods when used for the microarray-based prediction of the recurrence of metastases for stage II colon cancer patients.

CONCLUSIONS

The proposed sequential stopping rule for boosting algorithms can help to identify the optimal stopping iteration already during the fitting process of the algorithm, at least for the most common loss functions.

Localization of the telomeric (TTAGGG)n sequence in chicken (Gallus domesticus) chromosomes

The distribution of the highly conserved eukaryotic telomeric (TTAGGG)n sequence was investigated in chicken metaphase chromosomes using the FISH technique. Besides the expected telomeric locations, interstitial as well as centromeric locations of the (TTAGGG)n repeat were observed on several macrochromosomes. The microchromosomes display three discrete patterns of labeling with this repeat. The significance of this extreme-different distribution of the telomeric related sequence in chicken chromosomes may lie in pointing to structural events that might have occurred during the process of karyotype evolution.

Bartonella henselae induces NF-kappaB-dependent upregulation of adhesion molecules in cultured human endothelial cells: possible role of outer membrane proteins as pathogenic factors

The endothelium is a specific target for Bartonella henselae, and endothelial cell infection represents an important step in the pathogenesis of cat scratch disease and bacillary angiomatosis. Mechanisms of Bartonella-endothelial cell interaction as well as signaling pathways involved in target cell activation were analyzed. B. henselae strain Berlin-1, isolated from bacillary angiomatosis lesions of a human immunodeficiency virus-infected patient, potently stimulated human umbilical cord vein endothelial cells (HUVEC), as determined by NF-kappaB activation and enhanced adhesion molecule expression. These effects were accompanied by increased PMN rolling on and adhesion to infected endothelial cell monolayers, as measured in a parallel-plate flow chamber assay. Monoclonal antibodies against E-selectin significantly reduced PMN rolling and adhesion. In our hands, B. henselae Berlin-1 was substantially more active than the typing strain B. henselae ATCC 49882. E-selectin and ICAM-1 upregulation occurred for up to 9 days, as verified by Northern blotting and cell surface enzyme-linked immunosorbent assay. Induction of adhesion molecules was mediated via NF-kappaB activation and could be blocked by a specific NF-kappaB inhibitor. Additional studies indicated that B. henselae-induced effects did not require living bacteria or Bartonella lipopolysaccharides. Exposure of HUVEC to purified B. henselae outer membrane proteins (OMPs), however, reproduced all aspects of endothelial cell activation. In conclusion, B. henselae, the causative agent of cat scratch disease and bacillary angiomatosis, infects and activates endothelial cells. B. henselae OMPs are sufficient to induce NF-kappaB activation and adhesion molecule expression followed by enhanced rolling and adhesion of leukocytes. These observations identify important new properties of B. henselae, demonstrating its capacity to initiate a cascade of events culminating in a proinflammatory phenotype of infected endothelial cells.

Antagonism of glycerol trinitrate activity by an inhibitor of glutathione S-transferase

The in vitro spasmolytic activity of glycerol trinitrate was measured on the KCl-contraction of aorta strips from the rabbit. In the presence of sulphobromophthalein, a known inhibitor of glutathione S-transferase, the dose-activity curve for the nitrate was displaced to the right. Much smaller displacements were obtained with the control spasmolytic substances--papaverine and S-nitroso-N-acetylpenicillamine. It was confirmed that sulphobromophthalein inhibits glutathione S-transferase activity in aorta homogenates. Aorta extracts did not detectably catalyze the reaction between glutathione and sulphobromophthalein and the glutathione level was not decreased by treating the intact aorta with sulphobromophthalein. It is concluded that sulphobromophthalein acts as a specific antagonist of the spasmolytic activity of glycerol trinitrate, probably as a result of its inhibition of glutathione S-transferase. It thus seems probable that glutathione and glutathione S-transferase are involved in the pharmacological activation of the organic nitrates.

Centre of pressure displacements in trans-femoral amputees during gait

The aim of this study was to describe and quantify centre of pressure (CoP) displacement during walking in 12 unilateral trans-femoral amputees who had worn a prosthesis for at least 10 years. All subjects wore the same type of prosthesis and seven healthy subjects acted as controls. The CoP was acquired by an F-scan system and the displacements along the longitudinal axis of the foot versus time were quantified. An asymmetry of both temporal and spatial parameters of CoP patterns occurred between the sound and the prosthetic foot. The double support time and the time during which the CoP remained in the heel and mid-foot region were longer for the prosthetic limb. Conversely, the stance phase was longer for the sound limb, as was the time spent by the CoP in the forefoot. There was a redistribution of the time during which the CoP remained within the different zones of the sound foot with respect to the normal feet of the control subjects. The asymmetry seen in trans-femoral amputee stance is due not only to an abnormal spatio-temporal distribution of the CoP under the prosthetic leg, but also to a modification of the spatio-temporal distribution of the CoP under the sound foot compared to the normal foot. We conclude that an adaptation occurs in the control of the stance phase on the sound side during amputee gait.

Complex chromosomal rearrangement in a woman with multiple miscarriages

We report on a 23-yr-old healthy female with repeated miscarriages and a de novo complex chromosomal rearrangement (CCR) involving chromosomes 1, 2, 5 and 11 with 5 breakpoints. A review of cases reported in the last five yr is provided.

Incidence of diploid and disomic sperm nuclei in 45 infertile men

Sperm cells from 45 infertile patients were investigated for disomy rates of chromosomes 1, 7, 10, 17, X and Y as well as for diploidy by single- and double-target in-situ hybridization. The patients who attended the infertility clinic were aged 23-46 years. Semenograms showed that the patients had oligo-, astheno-, oligoastheno-, oligoterato-, oligoasthenoterato-, or asthenoteratozoospermia. The average disomy rates determined in the patients were similar for all chromosomes, ranging from 0.10% (chromosome Y) to 0.14% (chromosomes 10 and X). Diploidy was detected with a mean incidence of 0.1%. With the exception of two patients who exhibited significantly increased diploidy rates of 0.35 and 1.6%, neither disomy nor diploidy was increased in the group of infertile patients as compared to healthy, fertile males.

Centromeric association and non-random distribution of centromeres in human tumour cells

Centromere arrangement in interphase and metaphase cells of two human tumour cell lines was analysed using anti-kinetochore antibodies as immunofluorescent probes. In GLC1 interphase nuclei, kinetochores were non-randomly positioned around the nucleolus and close to the nuclear membrane. During S and early G2 phase, necklace-like strands of kinetochores were formed in the centre of the nucleus. The duplication of sister kinetochores during the G2 phase was not synchronized. At late G2 phase, a relatively random topological distribution of centromeres was observed with short linear arrays of sister kinetochores. Carefully spread metaphase plates of MDA-MB231 cells generally exhibited a linear alignment of centromeres and large centromeric clusters. In completely pulverized MDA-MB231 cells, centromeres showed a strong tendency to associate with each other.

Detection of t(11;22)(q24;q12) translocation breakpoint in paraffin-embedded tissue of the Ewing's sarcoma family by nested reverse transcription-polymerase chain reaction

Tumors of the Ewing's sarcoma family often present a major diagnostic challenge for the pathologist. In recent years, significant progress has been made in identifying characteristic chromosomal rearrangements associated with certain solid tumors. More than 85% of Ewing's sarcoma and related tumors present a specific t(11;22) (q24;q12) balanced translocation, which generates a fusion transcript of the EWS gene and the FLI-1 gene. The cloning of the t(11;22)(q24;q12) breakpoint has raised the possibility of using a reverse transcription-polymerase chain reaction (RT-PCR) based assay as a diagnostic tool. We report an improvement of the established method, which currently depends on fresh or snap-frozen tissue, so that it is possible to use formalin-fixed, paraffin-embedded tissue as a source of RNA. The described nested RT-PCR assay enables the pathologist to investigate retrospectively archival tumor samples or to confirm the diagnosis in cases where no fresh or frozen material is available.

Genetic counseling in a patient with XXY/XXXY/XY mosaic Klinefelter's syndrome: estimate of sex chromosome aberrations in sperm before intracytoplasmic sperm injection

OBJECTIVE

To report the sex chromosome aberrations in the sperm of a patient with mosaic Klinefelter's syndrome before ICSI.

DESIGN

Case report.

SETTING

Institute of Human Genetics, University Hospital

PATIENT(S)

A patient with an XXY/XXXY/XY mosaic Klinefelter's syndrome and extreme oligozoospermia.

INTERVENTION(S)

Skin biopsy, buccal smear, hair root sampling, and semen sampling.

MAIN OUTCOME MEASURE(S)

The karyotypes of three additional somatic cell systems and the ratio of sex chromosome aberrations in sperm.

RESULT(S)

After two-color fluorescence in situ hybridization of 202 interphase sperm nuclei, both the proportion of hyperhaploid 24, XY and 25, XXY sperm (5.0% and 0.5%, respectively) and of hyperhaploid 24, XX sperm (2.0%) were elevated. In contrast with peripheral lymphocytes, 93.9% of which showed sex chromosome aberrations, in the present patient only 7.5% of sperm proved to be hyperhaploid with an extra sex chromosome.

CONCLUSION(S)

The determination of sex chromosome aberrations in the sperm of a patient with mosaic Klinefelter's syndrome may provide additional information to estimate the transmission risk to his offspring.

delta Antigen in hepatitis B: immunohistology of frozen and paraffin-embedded liver biopsies and relation to HBV infection

The finding that the recently described hepatitis B (HB)-associated delta antigen (delta Ag) is preserved in pronase-treated, formalin-fixed paraffin sections allowed a combined prospective and retrospective immunohistological study of its occurrence in 571 liver biopsies. Among 116 frozen biopsies (69 HBAg seropositive, 47 HBAg seronegative) and 455 paraffin-embedded biopsies (296 HBAg seropositive, 159 HBAg-negative), delta Ag was found in 10 HBAg seropositive patients. With the exception of 1 patient with chronic persistent HB, all had chronic-active HB and none had acute HB; 5 patients were i.v. drug abusers. In follow-up biopsies, the delta Ag persisted with HBsAg for as long as 6 years. The expression of delta Ag showed similarities to the HBcAg system including nuclear localization, mixed nuclear cytoplasmic expression, and coexistence with anti-delta in blood. The findings are compatible with the hypothesis that delta Ag represents a transmissible, defective viral agent which requires HBV as a helper and may modulate, but not terminate, ongoing HBV infection.