In-vacuum optical isolation changes by heating in a Faraday isolator

We describe a model evaluating changes in the optical isolation of a Faraday isolator when passing from air to vacuum in terms of different thermal effects in the crystal. The changes are particularly significant in the crystal thermal lensing (refraction index and thermal expansion) and in its Verdet constant and can be ascribed to the less efficient convection cooling of the magneto-optic crystal of the Faraday isolator. An isolation decrease by a factor of 10 is experimentally observed in a Faraday isolator that is used in a gravitational wave experiment (Virgo) with a 10 W input laser when going from air to vacuum. A finite element model simulation reproduces with a great accuracy the experimental data measured on Virgo and on a test bench. A first set of measurements of the thermal lensing has been used to characterize the losses of the crystal, which depend on the sample. The isolation factor measured on Virgo confirms the simulation model and the absorption losses of 0.0016 +/- 0.0002/cm for the TGG magneto-optic crystal used in the Faraday isolator.

Targeted gene correction with 5' acridine-oligonucleotide conjugates

Single-stranded oligonucleotides (SSOs) mediate gene repair of punctual chromosomal mutations at a low frequency. We hypothesized that enhancement of DNA binding affinity of SSOs by intercalating agents may increase the number of corrected cells. Several biochemical modifications of SSOs were tested for their capability to correct a chromosomally integrated and mutated GFP reporter gene in human 293 cells. SSOs of 25 nucleotide length conjugated with acridine at their 5' end increased the efficiency of gene correction up to 10-fold compared to nonmodified SSOs. Acridine and psoralen conjugates were both evaluated, and acridine-modified SSOs were the most effective. Conjugation with acridine at the 3' end of the SSO inhibited gene correction, whereas flanking the SSO by acridine on both sides provided an intermediate level of correction. These results suggest that increasing the stability of hybridization between SSO and its target without hampering a 3' extension improves gene targeting, in agreement with the "annealing-integration" model of DNA repair.

Measurement of the optical parameters of the Virgo interferometer

The Virgo interferometer, aimed at detecting gravitational waves, is now in a commissioning phase. Measurements of its optical properties are needed for the understanding of the instrument. We present the techniques developed for the measurement of the optical parameters of Virgo. These parameters are compared with the Virgo specifications.

Uterine blood flow during supine rest and exercise after 28 weeks of gestation

OBJECTIVE

To test the null hypothesis that, after 28 weeks of gestation, uterine blood flow during supine rest and supine exercise is no different than uterine blood flow at left-lateral rest.

DESIGN

In vivo experimental study in pregnant women.

SETTING

Department of Obstetrics, MetroHealth Medical Center, Cleveland, OH, USA.

POPULATION

Fourteen, physically active, late-pregnant women who continued supine exercise throughout gestation.

METHODS

Studies were carried out between 29 and 38 weeks of gestation. Maternal blood pressure, maternal heart rate, and ultrasound estimates of volume blood flow in the right ascending branch of the uterine artery were obtained serially at rest in the left-lateral position, at rest in the supine position, during and immediately after 10 minutes of supine exercise, and again at rest in the left-lateral position. Exercise sessions included alternating 60- to 90-second periods of abdominal crunches and leg exercise at moderate/high intensity (Borg's rating of perceived exertion 14 +/- 1).

MAIN OUTCOME MEASURES

Blood pressure, heart rate, and uterine artery volume flow.

RESULTS

Data are presented as the mean +/- SD. Maternal heart rate and blood pressure were unchanged at supine rest but increased during supine exercise (heart rate increased from 76 +/- 9 to 98 +/- 12 beats per minute, mean arterial pressure increased from 81 +/- 6 to 102 +/- 12 mmHg). Volume flow fell from 410 +/- 93 to 267 +/- 73 cc/minute after 5 minutes of supine rest and then, during supine exercise, increased to 355 +/- 125 cc/minute. Uterine artery luminal diameter and blood flow correlated directly with tissue weights at birth (r(2) values between 0.32 and 0.59).

CONCLUSIONS

In physically active women, uterine blood flow decreases during both supine rest and supine exercise but the decrease in the former is twice that seen in the latter.

Outcome and morbidity of pancreas transplantation in a single Spanish institution

BACKGROUND

Pancreas transplantation is nowadays the only treatment to reestablish normal blood glucose in diabetic patients. Moreover, transplantation may also prevent and possibly even revert diabetes-related complications. We present our results with the first 4 years of a pancreas transplantation program.

MATERIALS AND METHODS

From February 2000 to June 2004, we performed 43 pancreas transplants in 42 recipients. In all cases the technique was enteric drainage of the exocrine secretions and systemic venous derivation to the inferior vena cava for endocrine secretions.

RESULTS

A simultaneous pancreas-kidney transplant was performed in 37 (88.1%) patients, a pancreas after kidney in 4 (9.5%) patients, and a retransplant in 1 (2.4%) patient. Glycosylated hemoglobin and C peptide returned to normal values in all cases. Patient and graft survivals were 91% and 84%, respectively, after a median follow-up of 19 months. The rate of reoperations was 31% with an overall 16% graft loss.

CONCLUSIONS

Our results were comparable to those of larger series.

Isolation, Tissue Distribution, and Molecular Characterization of Toxoplasma gondii From Free-Range Chickens From Guatemala

The prevalence of Toxoplasma gondii in free-ranging chickens is a good indicator of the prevalence of T. gondii oocysts in the soil because chickens feed from the ground. The prevalence of T. gondii in 50 free-range chickens (Gallus domesticus) from Guatemala was determined. Antibodies to T. gondii were assayed by the modified agglutination test (MAT). Antibodies were found in 37 (74%) chickens with titers of 1:5 (11), 1:10 (7), 1:20 (11), 1:40 (1), 1:80 (1), 1:160 (3), 1:1,280 (2), and 1:2,560 (1). Hearts, pectoral muscles, and brains of 19 chickens with MAT titers of 1:20 or more were bioassayed individually in mice. Tissues from the remaining 31 chickens with titers of 1:10 or lower were pooled and fed to 4 T. gondii-free cats (13 chickens with titers of less than 1:5 to 1 cat, 11 chickens with titers of 1:5 to 2 cats, and 7 chickens with titers of 1:10 to 1 cat). Feces of cats were examined for oocysts; they did not shed oocysts. Toxoplasma gondii was isolated from 8 chickens with MAT titers of 1:20 or more (from 1 of 11 chickens with a titer of 1:20 and all 7 chickens with a titer of 1:80 or more) from the heart, brain, and pectoral muscle (3); heart and pectoral muscle (1); and heart alone (4). Genotyping of these 8 isolates with the SAG2 locus indicated that 5 were type III and 3 were type 1. This is the first report of isolation of T. gondii from chickens from Guatemala.

Improving gene replacement by intracellular formation of linear homologous DNA

BACKGROUND

Gene targeting is a potential tool for gene therapy but is limited by the low rate of homologous recombination. Using highly homologous linear DNA improves gene targeting frequency but requires microinjection into nuclear cells to be effective. Because transfection of circular DNA is more efficient than transfection of linear DNA and adaptable to viral vectors, we developed a system for the intracellular release of linear fragments from circular plasmids.

METHODS

Only one cutting site inside the "donor" DNA was not convenient because it led to integration of exogenous sequences into the target. So we constructed several "donor" plasmids containing the homologous sequences flanked by two I-Sce I recognition sites. Expression of I-Sce I allowed intracellular delivery of "ends-out" (replacement) vectors. We compared the efficiency of different constructions to correct a mutated gfp target.

RESULTS

Co-transfection of "donor" plasmids and an I-Sce I expression vector into CHO cells enhanced the correction of an extrachromosomal mutated gfp target by at least 10 times. Maximum correction was observed with the greatest homology size and maximum effect of I-Sce I was obtained when the long hemi-sites of the duplicated I-Sce I sites were contiguous to the homologous sequence. Unexpectedly, the reverse orientation of I-Sce I sites provided little or no effect, probably due to the asymmetrical activity of the I-Sce I meganuclease.

CONCLUSIONS

Releasing homologous DNA fragments with I-Sce I enhances gene replacement. This work provides the basis for the future design of viral vectors for gene replacement.

The Baromodulatory Effect of Gamma Knife Irradiation of the Hypothalamus in the Obese Zucker Rat

OBJECTIVE

The aim of this study was to evaluate the effect on body weight set point over time of focused, subnecrotic doses of radiation via gamma knife (GK) to the hypothalamus of the genetically obese Zucker rat.

METHODS

A total of 36 adolescent animals were used in this experiment and placed in 6 groups of 6. The genetically obese homozygous Zucker rat was used in 4 groups (n = 24) and received GK, subcutaneous cobalt protoporphyrin (CoPP), both treatments combined or sham treatment. The heterozygous lean Zucker rat was used in 2 control groups (n = 12) and received either GK or sham treatment. All animals were weighed at the beginning of the experiment and at weekly intervals for 34 weeks. GK irradiation was accomplished using a specially designed stereotactic frame and a total dose of 40 Gy was given to 2 nearby targets in the medial hypothalamus. The drug subgroups received weekly subcutaneous injections. All animals were housed in the same environment with unlimited access to food.

RESULTS

There were no significant differences in weight between the lean GK and sham groups. For the obese cohort, beginning at week 7 and throughout the remainder of the experiment, there were significant and sustained reductions in weight set point for animals that received GK (p < 0.05) and CoPP (p < 0.05) compared to sham-treated animals. Curiously, there was no statistical difference between the combined treatment and sham subgroups, though there was a trend toward weight reduction (p < 0.10). With the exception of one animal in the obese GK cohort in which there was a small area of necrosis lateral to the target area, histopathological analysis failed to reveal any abnormalities. There were no gross behavioral abnormalities noted.

CONCLUSION

Our experimental results suggest that a single dose of GK irradiation to the hypothalamus can produce sustained reduction in the weight set point without emaciation in adolescent animals. The effect of this treatment is comparable to a well-studied drug therapy with a metalloporphyrin. We hypothesize that this involves a resetting of the hypothalamic set point for body weight through an as yet uncharacterized neuromodulatory effect.

The building blocks of planets within the 'terrestrial' region of protoplanetary disks

Our Solar System was formed from a cloud of gas and dust. Most of the dust mass is contained in amorphous silicates, yet crystalline silicates are abundant throughout the Solar System, reflecting the thermal and chemical alteration of solids during planet formation. (Even primitive bodies such as comets contain crystalline silicates.) Little is known about the evolution of the dust that forms Earth-like planets. Here we report spatially resolved detections and compositional analyses of these building blocks in the innermost two astronomical units of three proto-planetary disks. We find the dust in these regions to be highly crystallized, more so than any other dust observed in young stars until now. In addition, the outer region of one star has equal amounts of pyroxene and olivine, whereas the inner regions are dominated by olivine. The spectral shape of the inner-disk spectra shows surprising similarity with Solar System comets. Radial-mixing models naturally explain this resemblance as well as the gradient in chemical composition. Our observations imply that silicates crystallize before any terrestrial planets are formed, consistent with the composition of meteorites in the Solar System.

Enzymatic and electrochemical oxidation of N-hydroxy compounds. Redox potential, electron-transfer kinetics, and radical stability

A series of N-hydroxyacetanilide and 1-hydroxybenzotriazole analogues derivatized by various functional substituents were studied with regard to redox potential, oxidation by laccase, oxidative stability, and correlation to the electronic and steric properties of the substituents. It was found that substituents carrying conjugative/pi-electron function influenced the redox potential more than substituents carrying inductive/sigma-electron function, and that the electron-transfer from an N-hydroxy moiety to laccase was significantly affected by the redox potential. Electron-withdrawing substituents tended to reduce the electron density on the N-hydroxy group, leading to higher redox potential and lower oxidation rate. Bulky substitution or absence of N-phenyl tended to increase the Km of the N-hydroxy group, leading to lower oxidation rate. Oxidized N-hydroxy compounds were stabilized by N-phenyl or N-carbonyl group, but not by N-azo or highly strained structure. Potential implication of these effects on laccase-based, N-hydroxy compound-mediated biocatalysis is discussed.

Recreation in coastal waters: health risks associated with bathing in sea water

STUDY OBJECTIVE

To find out whether bathing in sewage polluted waters implies a danger to bathers' health and to determine the best microbiological indicator to predict the relation between bathing and the appearance of some symptoms.

DESIGN

Cohort study.

SETTING

City of Santander (north of Spain).

PARTICIPANTS

From the people going to four Santander beaches in the period from 1 July to 16 September 1998, a cohort of 2774 persons was recruited who agreed to participate in this study. Of those, 1858 successfully completed a follow up interview conducted in seven days. Respiratory, gastrointestinal, eye, and ear symptoms, and fever occurring during the seven day follow up were recorded.

MAIN RESULTS

A total of 136 participants (7.5%) reported symptoms. Visitors reported experiencing symptoms with more frequency than residents. Incidence rates of gastrointestinal, cutaneous and high respiratory tract symptoms were higher in bathers, but the differences were not significant. Total symptoms were related with the amount of total coliforms, faecal coliforms, and faecal streptococci in the water. Gastrointestinal and skin symptoms kept a positive trend with the degree of water pollution by total coliforms in both crude and adjusted analyses. An increased risk was observed in 2500-9999 total coliforms per 100 ml, a figure over the proposed standard, although below the European Union mandatory limit.

CONCLUSIONS

The results of this study suggest that total coliforms are the best predictors of the symptoms.

Beginning regular exercise in early pregnancy: effect on fetoplacental growth

OBJECTIVE

Our purpose was to test the null hypothesis that beginning regular, moderate-intensity exercise in early pregnancy has no effect on fetoplacental growth.

STUDY DESIGN

Forty-six women who did not exercise regularly were randomly assigned at 8 weeks either to no exercise (n = 24) or to weight-bearing exercise (n = 22) 3 to 5 times a week for the remainder of pregnancy. Outcome variables included antenatal placental growth rate and neonatal and placental morphometric measurements.

RESULTS

The offspring of the exercising women were significantly heavier (corrected birth weight: 3.75 +/- 0.08 kg vs 3.49 +/- 0.07 kg) and longer (51.8 +/- 0.3 cm vs 50.6 +/- 0.3 cm) than those born to control women. The difference in birth weight was the result of an increase in both lean body mass and fat mass. In addition, midtrimester placental growth rate was faster (26 +/- 2 cm(3)/wk vs 21 +/- 1 cm(3)/wk) and morphometric indexes of placental function were greater in the exercise group. There were no significant differences in neonatal percentage body fat, head circumference, ponderal index, or maternal weight gain.

CONCLUSIONS

These data indicate that beginning a moderate regimen of weight-bearing exercise in early pregnancy enhances fetoplacental growth.

Overlap of the anti-cardiolipin and anti-nucleosome responses of the (NZW X BXSB)F1 mouse strain: a new pattern of cross-reactivity for lupus-related autoantibodies

The association of anti-nuclear antigen (ANA) and anti-cardiolipin (CL) antibodies is often observed during systemic lupus erythematosus (SLE) or the primary anti-phospholipid syndrome, thereby raising the possibility of a relationship between these two autoantibody populations. To determine whether ANA and anti-CL antibodies can overlap, we derived, from a male (NZW x BXSB)F1 mouse, 14 hybridomas selected based on their capacities to react with CL and to label HEp-2 cell nuclei. Four of these anti-CL were IgG and bound to CL and phosphatidylserine in a cofactor-dependent manner and reacted strongly with nucleosomes. Variable region sequence analysis indicated that these four monoclonal antibodies (mAb) were derived from three independent B cell clones that used recurrent heavy and/or light chain immunoglobulin rearrangements, as assessed by comparison with each other and prototypic anti-CL mAb previously derived from different lupus mouse strains. These results indicate that anti-CL mAb can have overlapping cross-reactivities with nucleosomes, thereby defining a new category of SLE-related autoantibodies characterized by their capacities to recognize distinct supramolecular complexes, formed by the association of an anionic structure and a protein, that exert a strong selective pressure on autoreactive B cell clones.

Felodipine improves left ventricular emptying in patients with chronic heart failure: V-HeFT III echocardiographic substudy of multicenter reproducibility and detecting functional change

BACKGROUND

The echocardiographic substudy of the Vasodilator-Heart Failure Trial III (V-HeFT III) aimed to determine if felodipine treatment in patients with heart failure who were taking an angiotensin-converting enzyme inhibitor had a favorable effect on left ventricular (LV) structure and function. Earlier V-HeFT trials showed that hydralazine-isosorbide dinitrate improved ejection fraction (EF) and survival, whereas enalapril achieved greater survival with smaller increases in EF. Would the combination of a potent vasodilator and enalapril produce greater improvements in function and survival?

METHODS AND RESULTS

Doppler-echocardiographic data were collected from 260 males with heart failure who were randomized to felodipine or a placebo. Mean intrasubject differences between baseline, at 3 months, and at 12 months were compared. Intersite and intrareader reproducibilities were measured from duplicate recordings and readings. At 3 months, no changes in ultrasound variables from baseline occurred in either group. At 12 months, felodipine patients achieved greater increases in EF, shortening of LV end-systolic length, and increases in stroke volume index. Reproducibility coefficients of variation were 7.4% (EF), 6.0% (end-diastolic length), and 13.0% (stroke volume index).

CONCLUSIONS

The echocardiographic substudy showed that felodipine, added to heart failure therapy, increased EF, shortened end-systolic length, and increased stroke volume index. The changes were small and confirmed that reproducibility from multiple laboratories can be coordinated into a useful research tool.

Antiarrhythmic agents for atrial fibrillation: focus on prolonging atrial repolarization

Atrial fibrillation (AF) has been the subject of considerable attention and intensive clinical research in recent years. Current opinion among physicians on the management of AF favors the restoration and maintenance of normal sinus rhythm. This has several potential benefits, including the alleviation of arrhythmia-associated symptoms, hemodynamic improvements, and possibly a reduced risk of thromboembolic events. After normal sinus rhythm has been restored, antiarrhythmic therapy is necessary to reduce the frequency of AF recurrence. In the selection of an antiarrhythmic agent, both efficacy and safety should be taken into consideration. Many antiarrhythmic agents have the capacity to provoke proarrhythmia, which may result in an increase in mortality. This is of particular concern with sodium-channel blockers in the context of patients with structural heart disease. Flecainide and propafenone are well tolerated and effective in maintaining sinus rhythm in patients without significant cardiac disease but with AF. Recent interest has focused on the use of class III antiarrhythmic agents, such as amiodarone, sotalol, dofetilide (recently approved), ibutilide (approved for chemical conversion of AF and atrial flutter), and azimilide (still to be approved) in patients with AF and structural heart disease. To date, amiodarone and sotalol still hold the greatest interest, and although controlled clinical trials with these agents have been few, a number are in progress and some have been recently completed. These agents are effective in maintaining normal sinus rhythm in patients with paroxysmal and persistent AF and are associated with a low incidence of proarrhythmia when used appropriately. Because of the relative paucity of placebo-controlled trials of antiarrhythmic agents in patients with AF, experience until recently has tended to dictate treatment decisions. Increasingly, selection of drug therapy is being based on a careful and individualized benefit-risk evaluation by means of controlled clinical trials, an approach that is likely to dominate the overall approach to the control of atrial fibrillation in the largest numbers of cases of the arrhythmia. Pharmacologic therapy is likely to be dominated by compounds that exert their predominant effect by prolonging atrial repolarization.