Presence of suicidality as a prognostic indicator

BACKGROUND

Suicidal symptoms in depression are often thought to predict a higher severity of illness and a worse prognosis.

AIMS

To determine if suicidal ideation at the time of treatment for major depression can predict response to antidepressant medication in primary care.

SETTINGS AND DESIGN

A retrospective analysis of subjects receiving anti-depressant drugs in a primary care setting

METHODS AND MATERIAL

Nine depressed patients (14%) who acknowledged suicidality on the PHQ-9 depression scale were followed up for and compared to a group of 54 (86%) depressed patients (controls) who did not have suicidal thoughts for four months. All were given treatment with antidepressants and followed with a disease management protocol where the PHQ-9 was used as a systematic outcome measure.

STATISTICAL ANALYSIS

Descriptive measures and t-tests were utilized to show statistical significance.

RESULTS

There were no statistical differences in remission from depressive symptoms based on the PHQ-9 scale after antidepressant treatment, between patients with suicidal thoughts (56%) and those without (44%).

CONCLUSION

The presence of suicidality as a depressive symptom did not predict poorer clinical outcome when treating depression in the primary care setting in the patients studied.

Random-phase solitons in nonlinear periodic lattices

We predict the existence of random phase solitons in nonlinear periodic lattices. These solitons exist when the nonlinear response time is much longer than the characteristic time of random phase fluctuations. The intensity profiles, power spectra, and statistical (coherence) properties of these stationary waves conform to the periodicity of the lattice. The general phenomenon of such solitons is analyzed in the context of nonlinear photonic lattices.

Biofilm structure and function and possible implications for riverine DOC dynamics

Biofilms are major sites of carbon cycling in streams and rivers. Here we elucidate the relationship between biofilm structure and function and river DOC dynamics. Metabolism (extracellular enzymatic activity) and structure (algae, bacteria, C/N content) of light-grown (in an open channel) and dark-grown (in a dark pipe) biofilms were studied over a year, and variations in dissolved organic carbon (DOC) and biodegradable DOC (BDOC) were also recorded. A laboratory experiment on 14C-glucose uptake and DOC dynamics was also performed by incubating natural biofilms in microcosms. On the basis of our field (annual DOC budget) and laboratory results, we conclude that light-grown biofilm is, on annual average, a net DOC consumer. This biofilm showed a high monthly variability in DOC uptake/release rates, but, on average, the annual uptake rate was greater than that of the dark-grown biofilm. The higher algal biomass and greater structure of the light-grown biofilm may enhance the development of the bacterial community (bacterial biomass and activity) and microbial heterotrophic activity. In addition, the light-grown biofilm may promote abiotic adsorption because of the development of a polysaccharide matrix. In contrast, the dark-grown biofilm is highly dependent on the amount and quality of organic matter that enters the system and is more efficient in the uptake of labile molecules (higher 14C-glucose uptake rate per mgC). The positive relationships between the extracellular enzymatic activity of biofilm and DOC and BDOC content in flowing water indicate that biofilm metabolism contributes to DOC dynamics in fluvial systems. Our results show that short-term fluvial DOC dynamics is mainly due to the use and recycling of the more labile molecules. At the river ecosystem level, the potential surface area for biofilm formation and the quantity and quality of available organic carbon might determine the effects of biofilm function on DOC dynamics.

Spindle imaging: a new marker for optimal timing of ICSI?

BACKGROUND

The LC Polscope facilitates visualization of the meiotic spindle in human oocyte. This study aimed to investigate meiotic spindle assembly in correlation to time elapsed after HCG administration, and to determine whether spindle imaging may serve to indicate the likelihood of fertilization and embryo cleavage.

METHODS

Metaphase II (MII) oocytes from 103 couples who were being treated for male infertility were imaged with the Polscope prior to sperm injection. Spindle imaging was correlated to time elapsed from HCG administration, fertilization rate and embryo cleavage. The main outcome measures were spindle visualization, fertilization and embryo cleavage on day 3.

RESULTS

A total of 770 MII oocytes were imaged. A spindle was imaged in a significantly higher number of oocytes from >or=38 h after HCG administration compared with those in the <38 h group (78.1-81.5% versus 61.6%; P < 0.001). The fertilization rate in oocytes with a visible spindle was statistically higher compared with oocytes in which spindle could not be detected (70.4% versus 62.2%; P = 0.035). We found no relationship between spindle imaging and embryo cleavage on day 3.

CONCLUSIONS

Spindle imaging, in addition to first polar body appearance, is an accurate indicator for oocyte maturity. We suggest that spindle imaging be performed prior to sperm injection.

Formation of natural biofilms during chlorine dioxide and u.v. disinfection in a public drinking water distribution system

AIMS

The influence of two disinfection techniques on natural biofilm development during drinking water treatment and subsequent distribution is compared with regard to the supply of a high-quality drinking water.

METHODS AND RESULTS

The growth of biofilms was studied using the biofilm device technique in a real public technical drinking water asset. Different pipe materials which are commonly used in drinking water facilities (hardened polyethylene, polyvinyl chloride, steel and copper) were used as substrates for biofilm formation. Apart from young biofilms, several months old biofilms were compared in terms of material dependence, biomass and physiological state. Vital staining of biofilms with 5-cyano-2,3-ditolyl tetrazolium chloride (CTC) and the DNA-specific 4',6-diamidino-2-phenylindole (DAPI) staining resulted in a significant difference in physiological behaviour of biofilm populations depending on the disinfection technique. Compared with chlorine dioxide disinfection (0.12-0.16 mg l-1), the respiratory activities of the micro-organisms were increased on all materials during u.v. disinfection (u.v.254; 400 J m-2). The biofilm biocoenosis was analysed by in situ hybridization with labelled oligonucleotides specific for some subclasses of Proteobacteria. Using PCR and additional hybridization techniques, the biofilms were also tested for the presence of Legionella spp., atypical mycobacteria and enterococci. The results of the molecular-biological experiments in combination with cultivation tests showed that enterococci were able to pass the u.v. disinfection barrier and persist in biofilms of the distribution system, but not after chlorine dioxide disinfection.

CONCLUSIONS

The results indicated that bacteria are able to regenerate and proliferate more effectively after u.v. irradiation at the waterworks, and chlorine dioxide disinfection appears to be more applicative to maintain a biological stable drinking water.

SIGNIFICANCE AND IMPACT OF THE STUDY

As far as the application of u.v. disinfection is used for conditioning of critical water sources for drinking water, the efficiency of u.v. irradiation in natural systems should reach a high standard to avoid adverse impacts on human health.

Incoherent white light solitons in logarithmically saturable noninstantaneous nonlinear media

We analytically demonstrate the existence of white light solitons in logarithmically saturable noninstantaneous nonlinear media. This incoherent soliton has elliptic Gaussian intensity profile, and elliptic Gaussian spatial correlation statistics. The existence curve of the soliton connects the strength of the nonlinearity, the spatial correlation distance as a function of frequency, and the characteristic width of the soliton. For this soliton to exist, the spatial correlation distance must be smaller for larger temporal frequency constituents of the beam.

Increasing synthetic serum substitute (SSS) concentrations in P1 glucose/phosphate-free medium improves implantation rate: a comparative study

PURPOSE

To assess the comparative efficacy of IVF medium (MediCult, with 5.2 mM glucose) and a glucose/phosphate-free medium, P1 (Irvine Scientific), and to investigate the influence of increasing the serum supplementation (synthetic serum substitute; SSS; Irvine Scientific) to P1 on embryo development and implantation.

METHODS

Patients were randomly assigned to IVF medium (Group 1, cycles n = 172) or P1 supplemented with 10% SSS (Group 2, cycles n = 229) according to the medium scheduled for use on the day of oocyte retrieval. Another 555 IVF consequent cycles (Group 3) were performed using increased SSS concentrations (20%) in P1 medium.

RESULTS AND CONCLUSION

In this large series of IVF cycles, we herein demonstrate that significantly higher pregnancy and implantation rates were found when embryos were cultured in glucose/phosphate-free medium P1 supplemented with 20% SSS compared to supplementation with the lower SSS concentration and with IVF medium.

Structure of the DLM-1-Z-DNA complex reveals a conserved family of Z-DNA-binding proteins

The first crystal structure of a protein, the Z alpha high affinity binding domain of the RNA editing enzyme ADAR1, bound to left-handed Z-DNA was recently described. The essential set of residues determined from this structure to be critical for Z-DNA recognition was used to search the database for other proteins with the potential for Z-DNA binding. We found that the tumor-associated protein DLM-1 contains a domain with remarkable sequence similarities to Z alpha(ADAR). Here we report the crystal structure of this DLM-1 domain bound to left-handed Z-DNA at 1.85 A resolution. Comparison of Z-DNA binding by DLM-1 and ADAR1 reveals a common structure-specific recognition core within the binding domain. However, the domains differ in certain residues peripheral to the protein-DNA interface. These structures reveal a general mechanism of Z-DNA recognition, suggesting the existence of a family of winged-helix proteins sharing a common Z-DNA binding motif.

A randomized, double-blind, crossover clinical trial of diclofenac plus misoprostol versus acetaminophen in patients with osteoarthritis of the hip or knee

OBJECTIVE

To perform a randomized, double-blind, crossover clinical trial of diclofenac + misoprostol versus acetaminophen in ambulatory patients with osteoarthritis of the hip or knee.

METHODS

Patients in 12 ambulatory care settings were eligible if they were age >40 years and if they had Kellgren/Lawrence radiographic grade 2-4 osteoarthritis of the knee or hip and a score of > or =30 mm on a 100-mm visual analog pain scale. Patients were randomized to one of two groups, 75 mg diclofenac + 200 microg misoprostol twice daily or 1,000 mg acetaminophen 4 times daily (each for 6 weeks), and were then crossed over to the other treatment for 6 weeks. A placebo was included in each treatment regimen to enable double blinding. The primary outcome measures were the Western Ontario and McMaster Universities Osteoarthritis Index and the visual analog pain scale of the Multidimensional Health Assessment Questionnaire. Safety was assessed using a standard form to review adverse events.

RESULTS

We enrolled 227 patients, of whom 218 provided data for the first treatment period and 181 provided data for both treatment periods. Significantly higher levels of improvement in the primary outcomes were seen for diclofenac + misoprostol than for acetaminophen (P < 0.001). Adverse events were more common when patients took diclofenac + misoprostol (P = 0.046). Diclofenac + misoprostol was rated as "better" or "much better" by 57% of the 174 patients who provided such ratings for both treatment periods, while acetaminophen was rated as "better" or "much better" by 20% of these patients, and 22% reported no difference (P < 0.001). Differences favoring diclofenac + misoprostol over acetaminophen were greater in patients with more severe osteoarthritis according to baseline pain scores, radiographs, or number of involved joints.

CONCLUSION

Patients with osteoarthritis of the hip or knee had significantly greater improvements in pain scores over 6 weeks with diclofenac + misoprostol than with acetaminophen, although patients with mild osteoarthritis had similar improvements with both drugs. Acetaminophen was associated with fewer adverse events.

Abdominal CT findings in nephropathic amyloidosis of familial Mediterranean fever

To evaluate the abdominal CT features of reactive amyloidosis, abdominal CT scans of 20 patients with amyloidosis of familial Mediterranean fever (FMF) were reviewed and compared with abdominal CT scans of 2 control groups: 22 patients with chronic renal failure (CRF) due to non-amyloidotic kidney diseases and 40 patients with normal kidney function. The kidney size of patients with amyloidosis of FMF were found to vary during the course of the disease from normal or slightly larger than normal at the proteinuric phase, to smaller than normal and comparable to kidney size in CRF, at the uremic stage. Compared to kidney disease of other causes, more patients with FMF-amyloidosis had dense kidneys with coarse parenchymal calcification and calcification in other abdominal organs. Patients with FMF-amyloidosis had fewer aortic calcifications than patients with non-amyloidotic kidney disease. These findings suggest that kidney disease of reactive amyloidosis may have abdominal CT findings distinguishing it from other types of kidney diseases.

Prediction of cardiac mortality after myocardial infarction: the role of maximal treadmill stress echocardiography

Patients frequently undergo low-level exercise treadmill testing after acute myocardial infarction (MI) and, in the absence of inducible ischemia, a maximal test several weeks later. This study examines 203 patients who had 2-dimensional echocardiography before and after a maximal Bruce protocol exercise treadmill test performed 4 to 6 weeks after MI. The subjects were followed for a mean of 43 months (range 1 to 77 months). Predictors of cardiac mortality by multivariate or univariate analysis included an ejection fraction < or =40%, diabetes, age > or=70 years, and ischemia by exercise echocardiography but not by electrocardiography. Therefore, standard electrocardiographic monitoring during exercise treadmill testing 6 weeks after MI fails to predict cardiac mortality. The addition of pre-exercise and post-exercise treadmill stress echocardiography to readily available clinical parameters identifies those patients at greatest risk for cardiac death (resting ejection fraction < or=40%) and detects residual exercise-induced ischemia that may be of additional prognostic value.

Maternal anti-D prophylaxis during pregnancy does not cause neonatal haemolysis

OBJECTIVE

To evaluate signs of haemolysis in babies of Rh-D negative mothers who underwent prophylaxis with anti-D immunoglobulin during pregnancy.

DESIGN

The following were evaluated in all babies of Rh-D negative mothers born within a three month period in our department: haemoglobin level, packed cell volume, mean corpuscular volume, reticulocytes, bilirubin level, and direct Coombs' test (direct anti-globulin test). The babies were divided into two groups according to number of doses of anti-D immunoglobulin received by the mother (one or two), and then further divided by their Rh status (negative or positive). Findings were also compared with a control group of babies of O-Rh positive mothers.

RESULTS

The study group consisted of 101 babies and the control group of 37 babies. No statistically significant differences were found for any of the haematological variables between the babies of mothers who received one or two doses of anti-D immunoglobulin, or between the Rh negative babies (n = 35), and the controls. Although 20% of the Rh positive babies born to mothers receiving two doses of anti-D immunoglobulin had a positive result in the direct Coombs' test compared with only 2.4% of the babies of mothers treated with only one dose, no signs of haemolysis were documented in the babies with a positive Coombs test.

CONCLUSION

The prevention of Rh isoimmunisation with anti-D immunoglobulin (one or two doses) during pregnancy does not jeopardize the newborn. Blood group typing and direct Coombs' test should be performed in every newborn of an Rh negative mother to establish whether there is a necessity to administer anti-D. In the presence of a positive direct Coombs' test, the type of antibodies should be identified.

The making of a corporate athlete

Management theorists have long sought to identify precisely what makes some people flourish under pressure and others fold. But they have come up with only partial answers: rich material rewards, the right culture, management by objectives. The problem with most approaches is that they deal with people only from the neck up, connecting high performance primarily with cognitive capacity. Authors Loehr and Schwartz argue that a successful approach to sustained high performance must consider the person as a whole. Executives are, in effect, "corporate athletes." If they are to perform at high levels over the long haul, they must train in the systematic, multilevel way that athletes do. Rooted in two decades of work with world-class atheletes, the integrated theory of performance management addresses the body, the emotions, the mind, and the spirit through a model the authors call the performance pyramid. At its foundation is physical well-being. Above that rest emotional health, then mental acuity, and, finally, a spiritual purpose. Each level profoundly influences the others, and all must be addressed together to avoid compromising performance. Rigorous exercise, for instance, can produce a sense of emotional well-being, clearing the way for peak mental performance. Rituals that promote oscillation--the rhythmic expenditure and recovery of energy-link the levels of the pyramid and lead to the ideal performance state. The authors offer case studies of executives who have used the model to increase professional performance and improve the quality of their lives. In a corporate environment that is changing at warp speed, performing consistently at high levels is more necessary than ever. Companies can't afford to address employees' cognitive capacities while ignoring their physical, emotional, and spiritual well-being.

The zab domain of the human RNA editing enzyme ADAR1 recognizes Z-DNA when surrounded by B-DNA

The Zab domain of the editing enzyme ADAR1 binds tightly and specifically to Z-DNA stabilized by bromination or supercoiling. A stoichiometric amount of protein has been shown to convert a substrate of suitable sequence to the Z form, as demonstrated by a characteristic change in the CD spectrum of the DNA. Now we show that Zab can bind not only to isolated Z-forming d(CG)(n) sequences but also to d(CG)(n) embedded in B-DNA. The binding of Zab to such sequences results in a complex including Z-DNA, B-DNA, and two B-Z junctions. In this complex, the d(CG)(n) sequence, but not the flanking region, is in the Z conformation. The presence of Z-DNA was detected by cleavage with a Z-DNA specific nuclease, by undermethylation using Z-DNA sensitive SssI methylase, and by circular dichroism. It is possible that Zab binds to B-DNA with low affinity and flips any favorable sequence into Z-DNA, resulting in a high affinity complex. Alternatively, Zab may capture Z-DNA that exists transiently in solution. The binding of Zab to potential as well as established Z-DNA segments suggests that the range of biological substrates might be wider than previously thought.

Behçet's disease in Familial Mediterranean fever: characterization of the association between the two diseases

OBJECTIVES

Familial Mediterranean fever (FMF) is a genetic disease, characterized by attacks of fever and painful manifestations. Several vasculitides are more common in FMF than in the general population. The aim of the study was to define and characterize the association between FMF and Behcet's disease (BD), a form of vasculitis not previously related to FMF.

METHODS

We conducted a retrospective study in which FMF patients, also suffering from BD (FMF-BD), were recruited from about 4,000 patients registered in our clinic, using a computer survey. Patients identified by the screening process were examined, and those meeting the published criteria for the diagnoses of FMF and BD were classified as FMF-BD cases and compared with unselected FMF and BD controls.

RESULTS

The prevalence of BD was higher in FMF than in populations known to be rich in BD (eg, 16 per 4,000 in FMF compared with 1 per 104 in Japan, P < .001). FMF-BD cases and FMF or BD controls were comparable in most demographic, clinical, and laboratory aspects studied. However, more cases than FMF-controls were of Iraqi/Turkish origin and responded less favorably to colchicine. A higher proportion of cases than BD controls had skin, central nervous system, and gastrointestinal manifestations, originated from North Africa, and had family history of BD. In most cases, as in most respective controls, the severity of FMF was of intermediate grade and the extensiveness of BD was limited. The HLA B5 antigen was present in 53% of BD cases and 40% of BD controls.

CONCLUSIONS

BD should be included among the vasculitides complicating FMF. BD and FMF in patients with FMF-BD, and in patients suffering from each of these entities alone, are clinically and demographically comparable.

Management of oculus fragilis in Ehlers-Danlos type VI

PURPOSE

To describe an alternative, novel surgical approach to the repair of a ruptured globe in the second reported patient with keratoglobus, Ehlers-Danlos type VI, and normal lysyl hydroxylase.

METHODS

Under general anesthesia, a 360 degrees conjunctival peritomy was performed and the epithelium was removed from the keratoglobus cornea. Descemet's membrane and endothelium were removed from a fresh donor corneoscleral ring. An onlay epikeratoplasty was then performed and the entire donor corneoscleral button was secured to the sclera with 9-0 nylon suture. The conjunctiva was brought into position and tacked down over the edge of the donor graft. After 4 months, a full-thickness penetrating keratoplasty was then performed.

RESULTS

The patient ultimately had a ruptured globe in the fellow eye and thus required the identical procedure OU. Both eyes were successfully repaired with a final visual acuity OU of 20/100.

CONCLUSION

The described surgical approach allowed successful surgical repair of bilateral ruptured globes in a patient with keratoglobus, Ehlers-Danlos type VI, and normal lysyl hydroxylase levels. In the previous report of such a patient by Judisch et al. (1), the attempt at surgical repair was unsuccessful and ended in enucleation. The described surgical technique may be used to treat advanced keratoglobus or oculus fragilis.

Prednisone and aspirin improve pregnancy rate in patients with reproductive failure and autoimmune antibodies: a prospective study

PROBLEM

The study was conducted to investigate the efficacy of prednisone and aspirin in autoantibody seropositive patients with repeated in vitro fertilization embryo transfer (IVF ET) failure.

METHODS OF STUDY

The study group comprised 52 consecutive patients seropositive for non-organ-specific autoantibodies, i.e., anti-cardiolipin antibodies (ACA), anti-nuclear antibodies (ANA), anti-double-stranded (ds) DNA, rheumatoid factor (RF), and lupus anti-coagulant (LAC). These patients were treated with prednisone, 10 mg per day, and aspirin, 100 mg per day, starting 4 weeks before induction of ovulation in 52 IVF cycles.

RESULTS

The clinical pregnancy rate per cycle was 32.7% (17/52). No increased incidence of pregnancy complications, including premature labor, gestational diabetes mellitus, and pregnancy-induced hypertension, were found.

CONCLUSIONS

Combined treatment of prednisone for immunosuppression and aspirin as an anti-thrombotic agent, starting before ovulation induction, may improve pregnancy rate in autoantibody seropositive patients who have had repeated IVF-ET failures.

Nidovirus infections: experimental model systems of human neurologic diseases

The presence of terminally differentiated slow- and non-dividing cells in the central nervous system (CNS) provides a safe harbor for viral persistence and latency and constitutes a unique immunologic environment for viral infections. Studies of experimental model systems of viral infections of the CNS provide insight into mechanisms of viral persistence and immune-mediated pathology. Nidoviruses are comprised of 2 families of viruses, coronaviruses and arteriviruses, and are common pathogens of humans and a variety of animal species. Both families of viruses contain neurotropic strains that produce experimental neurologic diseases in rodents. These include acute meningitis and encephalitis; acute poliomyelitis; and chronic inflammatory, immune-mediated, demyelination. Coronavirus-induced demyelinating disease mimics many of the pathologic features of Multiple Sclerosis (MS).

The interaction between Z-DNA and the Zab domain of double-stranded RNA adenosine deaminase characterized using fusion nucleases

Zab is a structurally defined protein domain that binds specifically to DNA in the Z conformation. It consists of amino acids 133-368 from the N terminus of human double-stranded RNA adenosine deaminase, which is implicated in RNA editing. Zab contains two motifs with related sequence, Zalpha and Zbeta. Zalpha alone is capable of binding Z-DNA with high affinity, whereas Zbeta alone has little DNA binding activity. Instead, Zbeta modulates Zalpha binding, resulting in increased sequence specificity for alternating (dCdG)n as compared with (dCdA/dTdG)n. This relative specificity has previously been demonstrated with short oligonucleotides. Here we demonstrate that Zab can also bind tightly to (dCdG)n stabilized in the Z form in supercoiled plasmids. Binding was assayed by monitoring cleavage of the plasmids using fusion nucleases, in which Z-DNA-binding peptides from the N terminus of double-stranded RNA adenosine deaminase are linked to the nuclease domain of FokI. A fusion nuclease containing Zalpha shows less sequence specificity, as well as less conformation specificity, than one containing Zab. Further, a construct in which Zbeta has been replaced in Zab with Zalpha, cleaves Z-DNA regions in supercoiled plasmids more efficiently than the wild type but with little sequence specificity. We conclude that in the Zab domain, both Zalpha and Zbeta contact DNA. Zalpha contributes contacts that produce conformation specificity but not sequence specificity. In contrast, Zbeta contributes weakly to binding affinity but discriminates between sequences of Z-DNAs.

Crystallization and preliminary studies of the DNA-binding domain Za from ADAR1 complexed to left-handed DNA

The proteolytically defined Z-DNA binding domain Za of human adenosine deaminase type 1 (hADAR1) has been crystallized in complex with the DNA oligomer d(TCGCGCG). The crystals were obtained from a solution containing ammonium sulfate as precipitating agent and belong to the tetragonal space group P4212. A complete diffraction data set has been collected to a resolution of 2.4 A. The unit-cell dimensions are a = b = 85.9, c = 71.3 A. A Raman spectrum of the complex indicates that the DNA in the complex adopts the left-handed Z conformation.

Crystal structure of the Zalpha domain of the human editing enzyme ADAR1 bound to left-handed Z-DNA

The editing enzyme double-stranded RNA adenosine deaminase includes a DNA binding domain, Zalpha, which is specific for left-handed Z-DNA. The 2.1 angstrom crystal structure of Zalpha complexed to DNA reveals that the substrate is in the left-handed Z conformation. The contacts between Zalpha and Z-DNA are made primarily with the "zigzag" sugar-phosphate backbone, which provides a basis for the specificity for the Z conformation. A single base contact is observed to guanine in the syn conformation, characteristic of Z-DNA. Intriguingly, the helix-turn-helix motif, frequently used to recognize B-DNA, is used by Zalpha to contact Z-DNA.

Interpseudophakos Elschnig pearls associated with late hyperopic shift: a complication of piggyback posterior chamber intraocular lens implantation

We report 3 cases of bilateral piggyback lens implantation in which late hyperopic shift occurred associated with Elschnig pearl formation in the peripheral interface between the 2 lenses.

Proteolytic dissection of Zab, the Z-DNA-binding domain of human ADAR1

Zalpha is a peptide motif that binds to Z-DNA with high affinity. This motif binds to alternating dC-dG sequences stabilized in the Z-conformation by means of bromination or supercoiling, but not to B-DNA. Zalpha is part of the N-terminal region of double-stranded RNA adenosine deaminase (ADAR1), a candidate enzyme for nuclear pre-mRNA editing in mammals. Zalpha is conserved in ADAR1 from many species; in each case, there is a second similar motif, Zbeta, separated from Zalpha by a more divergent linker. To investigate the structure-function relationship of Zalpha, its domain structure was studied by limited proteolysis. Proteolytic profiles indicated that Zalpha is part of a domain, Zab, of 229 amino acids (residues 133-361 in human ADAR1). This domain contains both Zalpha and Zbeta as well as a tandem repeat of a 49-amino acid linker module. Prolonged proteolysis revealed a minimal core domain of 77 amino acids (positions 133-209), containing only Zalpha, which is sufficient to bind left-handed Z-DNA; however, the substrate binding is strikingly different from that of Zab. The second motif, Zbeta, retains its structural integrity only in the context of Zab and does not bind Z-DNA as a separate entity. These results suggest that Zalpha and Zbeta act as a single bipartite domain. In the presence of substrate DNA, Zab becomes more resistant to proteases, suggesting that it adopts a more rigid structure when bound to its substrate, possibly with conformational changes in parts of the protein.

Spectroscopic characterization of a DNA-binding domain, Z alpha, from the editing enzyme, dsRNA adenosine deaminase: evidence for left-handed Z-DNA in the Z alpha-DNA complex

Double-stranded RNA adenosine deaminase (ADAR1) is an ubiquitous enzyme in metazoa that edits pre-mRNA changing adenosine to inosine in regions of double-stranded RNA. Zalpha, an N-terminal domain of human ADAR1 encompassing 76 amino acid residues, shows apparent specificity for the left-handed Z-DNA conformation adopted by alternating (dGdC) polymers modified by bromination or methylation, as well as for (dGdC)13 inserts present in supercoiled plasmids. Here, a combination of circular dichroism, fluorescence, and gel-retardation studies is utilized to characterize recombinant Zalpha peptide and to examine its interaction with DNA. Results from laser-Raman spectroscopy experiments provide direct evidence for the existence of Z-DNA in peptide-DNA complexes.

The Zalpha domain from human ADAR1 binds to the Z-DNA conformer of many different sequences

Z-DNA, the left-handed conformer of DNA, is stabilized by the negative supercoiling generated during the movement of an RNA polymerase through a gene. Recently, we have shown that the editing enzyme ADAR1 (double-stranded RNA adenosine deaminase, type 1) has two Z-DNA binding motifs, Zalpha and Zbeta, the function of which is currently unknown. Here we show that a peptide containing the Zalpha motif binds with high affinity to Z-DNA as a dimer, that the binding site is no larger than 6 bp and that the Zalpha domain can flip a range of sequences, including d(TA)3, into the Z-DNAconformation. Evidence is also presented to show that Zalpha and Zbeta interact to form a functional DNA binding site. Studies with atomic force microscopy reveal that binding of Zalpha to supercoiled plasmids is associated with relaxation of the plasmid. Pronounced kinking of DNA is observed, and appears to be induced by binding of Zalpha. The results reported here support a model where the Z-DNA binding motifs target ADAR1 to regions of negative supercoiling in actively transcribing genes. In this situation, binding by Zalpha would be dependent upon the local level of negative superhelicity rather than the presence of any particular sequence.

Measuring carotid artery stenosis using CT angiography: the dilemma of artifactual lumen eccentricity

OBJECTIVE

This study assesses artifactual luminal distortion, or eccentricity, that affects measurement of stenosis on CT angiography performed with a variety of helical protocols.

MATERIALS AND METHODS

A 32-vessel carotid artery phantom was built with five known grades of stenoses (25%, 50%, 75%, 88%, and 94%) and three lengths of stenosis (1, 3, and 5 mm). This phantom was scanned with conventional and 1.0-, 1.5-, and 2.0-pitch helical CT with slice thicknesses of 2, 4, and 8 mm, and three vessel orientations: parallel, 45 degrees oblique, and perpendicular to the z-axis. Oblique multiplanar reconstruction was performed with the latter two vessel orientations to produce images similar to the parallel to z-axis orientation. The cross-sectional images were then used to measure the maximum and minimum (longest and shortest) luminal diameters in and out of each stenosis at a computer workstation by a single investigator who was unaware of the scanning technique. Percentage of stenosis was assessed by three methods: cross-sectional area in and out of the stenosis, maximum diameter out of stenosis and minimum in stenosis (North American Symptomatic Carotid Endarterectomy Trial method), and minimum diameter in and out of the stenosis. Comparisons were made with the gold standard using the equation (measured percentage of stenosis-actual percentage of stenosis) based on known luminal diameters of the phantom. Luminal eccentricity was assessed for each of the vessels and scanning parameters as a ratio of minimum to maximum diameters.

RESULTS

All three methods of measuring stenoses were strongly affected by luminal eccentricity. The North American Symptomatic Carotid Endarterectomy Trial method overestimated percentage of stenosis an average of 1.64%. The most accurate results were obtained when using the minimum diameter in and out of the stenoses (-0.45% from the gold standard). Eccentricity was significantly greater in stenoses than in normal lumen (p < .0001) and when the vessels were oriented perpendicular to the z-axis (p = .0003). A progressive increase in eccentricity was seen in the 4- and 8-mm slice thicknesses and the 3- and 5-mm-long stenoses (p < .001; p < .001).

CONCLUSION

Artifactual luminal eccentricity has significant implications for measuring percentage of stenosis revealed by CT angiography. Eccentricity increases in longer stenoses, thicker slices, and vessels oriented perpendicular to the z-axis. With CT angiography, measurement of minimum diameters in and out of a stenosis provides the most accurate assessment of percentage of stenosis.

Closure of Pfannenstiel skin incisions. Staples vs. subcuticular suture

OBJECTIVE

To compare skin closure with staples and subcuticular suture.

STUDY DESIGN

Obstetric patients undergoing cesarean section with a Pfannenstiel incision were prospectively randomized to skin closure with staples or subcuticular suture. Pain and cosmesis were assessed postoperatively.

RESULTS

Patients reported significantly less pain following subcuticular closure at both the time of discharge (P < or = .01) and the postoperative visit (P < or = .002). Incisions closed with subcuticular suture were found to be more cosmetically attractive by both patients (P = .04) and physicians (P = .01) at the postoperative visit.

CONCLUSION

Pfannenstiel skin incisions closed with subcuticular closure following cesarean section result in less postoperative discomfort and are more cosmetically appealing at the six-week postoperative visit as compared to incisions closed with staples.

Peak expiratory flow rate in normal pregnancy

OBJECTIVE

To determine whether peak expiratory flow rate changes with pregnancy and advancing gestation.

METHODS

We measured the peak expiratory flow rate in 57 women during each trimester of pregnancy and postpartum. During four visits, all subjects exhaled forcefully three times into a peak flow meter. For each visit, the best of three attempts defined their peak expiratory flow rate. Using accepted standard nomograms, we normalized peak expiratory flow rate with respect to height and age. Using analysis of variance, we compared the mean normalized peak expiratory flow rates in each of the trimesters and postpartum.

RESULTS

The subjects' peak expiratory flow rates did not change significantly during the three trimesters and postpartum (P = .317). The mean peak expiratory flow rates for the three trimesters and postpartum were 434 +/- 18, 452 +/- 16, 444 +/- 15, and 450 +/- 16 (values in liters per minute +/- 95% confidence intervals [CIs]). The mean normalized peak expiratory flow rates for the three trimesters and postpartum were 0.92 +/- 0.036, 0.95 +/- 0.032, 0.94 +/- 0.030, and 0.95 +/- 0.031 (values +/- 95% CI).

CONCLUSIONS

This study demonstrates that peak expiratory flow rate does not change with pregnancy and advancing gestation. Therefore, testing peak expiratory flow rate in pregnancy is valid, and physicians can use peak expiratory flow rate accurately and reliably in the management of pregnant women with asthma.

Telomere length does not change during senescence of the ascomycete Podospora anserina

All strains of the filamentous fungus Podospora anserina are characterized by a well defined life span. Senescence is controlled by nuclear and extranuclear genetic traits. In order to test whether or not the ends of the chromosomes of this ascomycete shorten during senescence and thus telomere shortening may be linked to the well analyzed, age-related reorganizations of the mitochondrial DNA (mtDNA), we analyzed the genomic DNA of P. anserina wild-type strain s. We found that, although the mtDNA becomes reorganized when cultures age, the telomeres remain constant suggesting that telomere shortening does not play a major role in normal aging of this particular biological system.

Multicenter comparison of micronized fenofibrate and simvastatin in patients with primary type IIA or IIB hyperlipoproteinemia

In 12 weeks of active treatment, we compared the efficacy and safety of a new (micronized) formulation of fenofibrate (F) (200 mg/day) with that of simvastatin (S) (20 mg/day), an inhibitor of hydroxy-methyl-glutaryl coenzyme A (HMG-CoA)-reductase. Men and women with primary hyperlipoproteinemia (HLP) with low-density lipoprotein (LDL) cholesterol level 180-300 mg/dl and triglyceride level < 500 mg/dl had dietary treatment for 8 weeks, and 133 (2 of 3 type IIa, 1 of 3 type IIb HLP) were randomized. The decrease in total cholesterol differed between type IIa patients (F - 17.9 vs. S - 25.8%), the decrease in triglyceride levels between the type II b groups (F - 52.8 vs. S - 14%), whereas the degree of decrease in LDL cholesterol (F - 20.9 vs. S - 34.9%) differed among all patients. Despite the difference in LDL cholesterol decrease, no difference was noted in total apolipoprotein (apo) B lowering (F - 20.8 and S - 26.5%). Increases in high-density lipoprotein (HDL) cholesterol (F + 18.5 vs. S + 15%) differed specifically in type IIb patients (F + 33.6 vs. S + 11.4%), accompanied by a more pronounced increase in apo AI with fenofibrate (F + 10.5% vs. S no change). Improvement in the ratios of total cholesterol/HDL cholesterol and apo AI/apo B occurred similarly with both drugs. Only fenofibrate, not simvastatin, decreased both fibrinogen (-10.3 vs. + 3.6%) and uric acid (-25% vs. no change) in type IIa and type IIb patients. Safety parameters reflected drug-specific known side effects, underscoring the safety of both drugs in addition to their efficacy in lipid lowering. Besides its advantages in type IIb hyperlipidemia, micronized fenofibrate proved a potent drug in decreasing total and LDL cholesterol and in very effectively decreasing apo B-containing lipoproteins, which is a recommendation for its use in primary hypercholesterolemia.

Mutual adaptation of bacteriophage fd, pfd plasmids and their host strains

The synthetic plasmid pfdC1 with the replication origin of phage fd and fd gene 2 grows autonomously in E. coli cells. DNA sequencing revealed several mutations compared to the fd genome causing reduced expression of viral gene 2 protein, which can be toxic for the host cell. Another adaptation was noticed for E. coli strains with a copy of fd gene 2 on the F-episome and a pfdA-plasmid with a minimal fd replication origin, when maintained at 42 degrees C. The carrier cells adjusted their cellular metabolism to these stress conditions, whereas replication functions of the plasmid or expression of fd gene 2 on the F-episome were not changed. The filamentous bacteriophages tend to reduce their genome size into miniphages, which was also observed for phages with an antibiotic resistance gene. Bacteriophages with a transposon insertion in the viral gene 2 had a tendency to restore the mutated gene by exchange with the functional gene 2 carried in recA-host cells. Mobilization of pfd-plasmids with RP4 transfer functions was reduced due to interference of replication and transfer in the rolling circle mode. The vectors used in these studies can also be applied as cloning vectors, which are compatible with many other plasmid vectors.

Phorbol esters inhibit insulin-induced receptor down-regulation in cultured human lymphocytes: association with diminished insulin receptor autophosphorylation

Exposure of cells to phorbol 12-myristate 13-acetate (PMA) has been reported to result in resistance to the acute biological effects of insulin and an associated reduction in insulin-receptor tyrosine kinase activity. To investigate the relationship of insulin receptor autophosphorylation with a longer-term action of insulin the effect of PMA on insulin-stimulated receptor down-regulation was examined in cultured human lymphocytes (IM-9). Lymphocytes bound [3H]phorbol dibutyrate specifically with characteristics typical of binding to protein kinase C (PKC). Acute exposure (30 min) to PMA resulted in a transient decrease of insulin binding which is consistent with a decrease in receptor number. Chronic (18 h) exposure to PMA (5 nM) resulted in inhibition of insulin-induced down-regulation of its cognate receptor. Sphingosine, an inhibitor of PKC, or chronic pre-exposure to a high concentration of PMA (1 microM), which is known to inactivate PKC, blocked the effect of PMA. PMA inhibited insulin-stimulated receptor internalization by 26% and receptor degradation by 82%. Exposure of intact cells to PMA followed by insulin treatment inhibited insulin-receptor autophosphorylation subsequently assayed in vitro, as well as beta-subunit tyrosine phosphorylation in situ. In summary, PMA inhibited insulin-stimulated receptor down-regulation via activation of PKC. This was associated with an inhibition of both receptor internalization and receptor degradation. There was a concomitant inhibition of receptor tyrosine autophosphorylation consistent with a requirement of receptor kinase activation for both short-term and long-term biological effects of insulin.

Site-directed and transposon-mediated mutagenesis with pfd-plasmids by electroporation of Erwinia amylovora and Escherichia coli cells

The suicide plasmid pfdA31-Tn5 was constructed to mutagenize Erwinia amylovora and Escherichia coli strains by electorporation. This vector carries the bacteriophage fd replication origin, a beta-lactamase gene and the transposon Tn5. For propagation the plasmid depends on host cells producing fd gene-2 protein. Electroporation of E.amylovora or E.coli cells with plasmid pfdA31-Tn5 yielded more than 10(4) transposition events per micrograms DNA. We have produced and characterized transposon mutants of E.amylovora affecting either galactose metabolism or the synthesis of the phytotoxin (L)-2,5-dihydrophenylalanine. A Tn5-insertion in a gene, involved in exopolysaccharide synthesis of E.amylovora strain Ea7/74, was subcloned into vector pfdA31 and used to mutagenize E.amylovora strain Ea1/79 by site-directed recombination.