Multi-modal imaging: simultaneous MRI and ultrasound imaging for carotid arteries visualization

The purpose of this study is to examine the feasibility of simultaneous Magnetic Resonance Imaging (MRI) and Ultrasound (US) imaging in visualizing anatomical structures and functions in human carotid arteries. US has high frame rate in visualizing dynamic changes while high resolution MRI is capable of capturing volumetric structures with the best tissue contrast. Concurrent multi-modal image acquisition allows fusion of US Doppler flow measurement with volumetric MRI. We present a method for acquiring MR images in a known orientation with respect to US image by passive fiducial tracking and demonstrate concurrent real-time imaging in the right Common Carotid Artery (CCA) in both modalities. Preliminary results suggest that US and MRI can operate concurrently with proper shielding. Dispensability measurements are feasible on both modalities at the co-incident plane.

AFM capabilities in characterization of particles and surfaces: from angstroms to microns

Scanning probe microscopy (SPM), invented 25 years ago, is now routinely employed as a surface characterization technique. Atomic force microscopy (AFM) is the most widely used form of SPM, since AFM can be used in ambient conditions with minimal sample preparation. Examples of applications relevant to cosmetics include, but are not limited to, hair and skin roughness measurements and powder particle and nano-emulsion characterization. AFM is well suited for individual particle characterization, especially for measurements of volume, height, size, shape, aspect ratio, and particle surface morphology. Statistical distributions for a large set of particles can be generated through single-particle analysis techniques (i.e., ensemble-like information). AFM is better capable of resolving complex particle-size distributions than dynamic light-scattering (DLS). Single-particle analysis techniques with AFM can be more cost- and time-effective than analyses using scanning electron microscopy (SEM). However, AFM offers resolution that is comparable to or greater than SEM or transmission electron microscopy (TEM) and routinely allows direct measurements of the particle height and volume and produces images easily displayed in a quantified 3D format.

Impact of health educational programmes on the prevalence of enterobiasis in schoolchildren in Thailand

Enterobiasis is a worldwide prevalent disease particularly in low income areas. The budget needed for the prevention, treatment and eradication of the disease has thus far frustrated the limited budgets of global public health systems. A study was undertaken to determine if education in addition to medical treatment of enterobiasis could make a difference to the rates of infection. A total of 777 children (399 male and 378 female) from 11 elementary schools in five districts of Samut Prakan Province, Thailand were examined between December 2000 and March 2002. In five of the 11 schools studied, medical treatments were applied, followed by a programme of educating the children in the prevention of infection. Children in the remaining six schools received medical treatment only. The study showed a decrease in infections among children who received supplementary education. This decrease was significant in comparison to the decrease shown among children who received medical treatment only. The study therefore showed that educating high risk individuals played a key role in the prevention of enterobiasis.

Are transthoracic echocardiographic parameters associated with atrial fibrillation recurrence or stroke? Results from the Atrial Fibrillation Follow-Up Investigation of Rhythm Management (AFFIRM) study

OBJECTIVES

The purpose of this study was to evaluate the associations of transthoracic echocardiographic parameters with recurrent atrial fibrillation (AF) and/or stroke.

BACKGROUND

The Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study, an evaluation of elderly patients with AF at risk for stroke, provided an opportunity to evaluate the implications of echocardiographic parameters in patients with AF.

METHODS

Transthoracic echocardiographic measures of mitral regurgitation (MR), left atrial (LA) diameter, and left ventricular (LV) function were evaluated in the AFFIRM rate- and rhythm-control patients who had sinus rhythm resume and had these data available. Risk for recurrent AF or stroke was evaluated with respect to transthoracic echocardiographic measures.

RESULTS

Of 2,474 patients studied, 457 had > or =2(+)/4(+) MR, and 726 had a LA diameter >4.5 cm. The LV ejection fraction was abnormal in 543 patients. The cumulative probabilities of at least one AF recurrence/stroke were 46%/1% after 1 year and 84%/5% by the end of the trial (> 5 years), respectively. Multivariate analysis showed that randomization to the rhythm-control arm (hazard ratio [HR] = 0.64; p < 0.0001) and a qualifying episode of AF being the first known episode (HR = 0.70; p < 0.0001) were associated with decreased risk. Duration of qualifying AF episode >48 h (HR = 1.55; p < 0.0001) and LA diameter (p = 0.008) were associated with an increased risk of recurrent AF. Recurrent AF was more likely with larger LA diameters (HR = 1.21, 1.16, and 1.32 for mild, moderate, and severe enlargement, respectively). No transthoracic echocardiographic measures were associated with risk of stroke.

CONCLUSIONS

In the AFFIRM study, large transthoracic echocardiographic LA diameters were associated with recurrent AF, but no measured echocardiographic parameter was associated with stroke.

Quality of life in atrial fibrillation: the Atrial Fibrillation Follow-up Investigation of Rhythm Management (AFFIRM) study

OBJECTIVE

The objective of this prespecified substudy of the AFFIRM study, in which no differences in survival or event rates were found in patients with atrial fibrillation (AF) randomized to either rate control or rhythm control, was to test the null hypothesis that quality of life (QoL) is equal with rate- versus rhythm-control treatment strategies in AF.

METHODS

Fifty-six (25%) of AFFIRM sites were randomly selected to recruit AFFIRM patients for the QoL substudy. Instruments used in the QoL assessment were (1) Perceived Health; (2) the Cantril Ladder of Life; (3) the Short Form 36 survey; (4) the QoL Index; and (5) the Symptom Checklist: Frequency and Severity. Data were collected at baseline, 2 months, 12 months, and annually; data are reported through 4 years of follow-up.

RESULTS

Baseline characteristics of the AFFIRM QoL patients (n = 716) were generally similar to those of the rest of AFFIRM patients. Quality-of-life scores were similar in rate- and rhythm-control assignment groups at all time points. Quality-of-life scores were similar whether the actual rhythm was sinus or AF. Scores increased from baseline to subsequent time points similarly for both groups; these improvements were not additive over time.

CONCLUSIONS

Quality of life was comparable between rate- and rhythm-control treatment strategies. In addition, QoL was similar with sinus rhythm versus AF. Attempts to improve QoL by restoring sinus rhythm will usually be unsuccessful.

Characterization of the time dependence of polarization mode dispersion

We elaborate on a recently proposed model of the temporal dependence of polarization mode dispersion in long fiber links. We evaluate the probability that a channel of a wavelength-division multiplexed system never incurs an outage, and the range of frequency over which the parameters that characterize the temporal statistics of the differential group delay are correlated.

Profound infantile neuroretinal dysfunction in a heterozygote for the CLN3 genetic defect

The neuronal ceroid-lipofuscinoses are a group of diseases that are characterized by progressive neuroretinal symptomatology, progressive accumulation of autofluorescing waxy lipopigments (ceroid-lipofuscin) within the brain and other tissues, and cerebral atrophy. Juvenile neuronal ceroid-lipofuscinosis, or Batten disease, is a form of neuronal ceroid-lipofuscinosis that is characterized by onset of neuroretinal symptoms between 4 and 10 years. Juvenile neuronal ceroid-lipofuscinosis is the most common type of neuronal ceroid-lipofuscinosis in the United States and Europe and is inherited as an autosomal recessive genetic disorder. Research in the last decade has led to the identification of the responsible gene for juvenile neuronal ceroid-lipofuscinosis, which is designated as CLN3. CLN3 is located on chromosome 16p11.2-12.1. The major mutation is a 1.02 kb deletion, which removes exons 7 and 8. Both homozygotic and heterozygotic deletions at the CLN3 gene site have been associated with the clinical syndromes of juvenile neuronal ceroid-lipofuscinosis. We report a possible atypical case of neuronal ceroid-lipofuscinosis, an infant, who presented at 5 months of age with a lack of developmental milestones, poor vision, severe retinopathy, intractable seizures, and progressive cerebral atrophy. Extensive laboratory investigations, including thorough metabolic evaluations, were unremarkable except for neuroimaging studies, electroencephalography, and electroretinography, all of which showed abnormalities confirming both cerebral and retinal degeneration. Although skin and conjunctival biopsies did not show classic fingerprint cytosomes by electron microscopic study, which characterize juvenile neuronal ceroid-lipofuscinosis, a diagnosis of an atypical form of juvenile neuronal ceroid-lipofuscinosis was suspected on the basis of the clinical picture. The retinal abnormalities, surprisingly, were those believed to be diagnostic of juvenile-onset neuronal ceroid-lipofuscinosis, or Batten disease. Subsequently, a heterozygous mutation for the common 1.02 kb deletion characteristic of juvenile neuronal ceroid-lipofuscinosis was established.

Activation of a meiotic checkpoint during Drosophila oogenesis regulates the translation of Gurken through Chk2/Mnk

BACKGROUND

During Drosophila oogenesis, unrepaired double-strand DNA breaks activate a mei-41-dependent meiotic checkpoint, which couples the progression through meiosis to specific developmental processes. This checkpoint affects the accumulation of Gurken protein, a transforming growth factor alpha-like signaling molecule, as well as the morphology of the oocyte nucleus. However, the components of this checkpoint in flies have not been completely elucidated.

RESULTS

We show that a mutation in the Drosophila Chk2 homolog (DmChk2/Mnk) suppresses the defects in the translation of gurken mRNA and also the defects in oocyte nuclear morphology. We also found that DmChk2 is phosphorylated in a mei-41-dependent pathway. Analysis of the meiotic cell cycle progression shows that the Drosophila Chk2 homolog is not required during early meiotic prophase, as has been observed for Chk2 in C. elegans. We demonstrate that the activation of the meiotic checkpoint affects Dwee1 localization and is associated with DmChk2-dependent posttranslational modification of Dwee1. We suggest that Dwee1 has a role in the meiotic checkpoint that regulates the meiotic cell cycle, but not the translation of gurken mRNA. In addition, we found that p53 and mus304, the Drosophila ATR-IP homolog, are not required for the patterning defects caused by the meiotic DNA repair mutations.

CONCLUSIONS

DmChk2 is a transducer of the meiotic checkpoint in flies that is activated by unrepaired double-strand DNA breaks. Activation of DmChk2 in this specific checkpoint affects a cell cycle regulator as well as mRNA translation.

Targeted mutagenesis by homologous recombination in D. melanogaster

We used a recently developed method to produce mutant alleles of five endogenous Drosophila genes, including the homolog of the p53 tumor suppressor. Transgenic expression of the FLP site-specific recombinase and the I-SceI endonuclease generates extrachromosomal linear DNA molecules in vivo. These molecules undergo homologous recombination with the corresponding chromosomal locus to generate targeted alterations of the host genome. The results address several questions about the general utility of this technique. We show that genes not near telomeres can be efficiently targeted; that no knowledge of the mutant phenotype is needed for targeting; and that insertional mutations and allelic substitutions can be easily produced.

Cost-effectiveness of the implantable cardioverter-defibrillator versus antiarrhythmic drugs in survivors of serious ventricular tachyarrhythmias: results of the Antiarrhythmics Versus Implantable Defibrillators (AVID) economic analysis substudy

BACKGROUND

The implantable cardioverter-defibrillator (ICD) is an effective but expensive device. We used prospectively collected data from a large randomized clinical trial of secondary prevention of life-threatening ventricular arrhythmias to determine the cost-effectiveness of the ICD compared with antiarrhythmic drug (AAD) therapy, largely with amiodarone.

METHODS AND RESULTS

Charges for initial and repeat hospitalizations, emergency room, and day surgery stays and the costs of antiarrhythmic drugs were collected on 1008 patients. Detailed records of all other medical encounters and expenses were collected on a subgroup of 237 patients. Regression models were then created to attribute these expenses to the rest of the patients. Charges were converted to 1997 costs using standard methods. Costs and life years were discounted at 3% per year. Three-year survival data from the Antiarrhythmics Versus Implantable Defibrillators trail were used to calculate the base-case cost-effectiveness (C/E) ratio. Six-year, twenty-year, and lifetime C/E ratios were also estimated. At 3 years, total costs were $71 421 for a patient taking AADs and $85 522 for a patient using an ICD, and the ICD provided a 0.21-year survival benefit over AAD treatment. The base-case C/E ratio was thus $66 677 per year of life saved by the ICD compared with AAD therapy (95% CI, $30 761 to $154 768). Six- and 20-year C/E ratios remained stable between $68 000 and $80 000 per year of life saved.

CONCLUSIONS

The ICD is moderately cost-effective for secondary prevention of life-threatening ventricular arrhythmias, as judged from prospectively collected data in a randomized clinical trial.

Surface and subsurface irrigation with effluents of different qualities and presence of Cryptosporidium oocysts in soil and on crops

A large variety of human pathogens are excreted in wastewater including bacteria, viruses, protozoan cysts and helminth eggs. In raw sewage, human pathogens reach high numbers, thereafter decreasing successively at each treatment step. However, the final effluents still contain a large fraction of these pathogens that may pose a serious public health. Among the various crops irrigated with effluents, vegetables are the most vulnerable to contamination. Vegetables, usually eaten raw (uncooked) or with rich dressings (causing regrowth of some pathogenic bacteria) pose the main threat to humans. The importance of microbiological and parasitological criteria for reused water has been repeatedly emphasized. Some microbiological recommendations based on epidemiological data have been established for untreated wastewater, there is still a need to define the criteria for effluent quality required for unrestricted crop irrigation. This paper presents a field study comparison of two irrigation methods: surface and subsurface of field crops (mainly vineyard) and follow-up of Cryptosporidium oocysts in soil at different depths (0 to 90 cm). Oocysts were isolated at all depths without a clear pattern of distribution (0 to 640 oocysts/g). In addition different vegetables irrigated with different effluent qualities were tested for the presence of Cryptosporidium oocysts and Giardia cysts. The highest prevalence of oocysts was found on zucchini that has a sticky and hairy outer surface (80 to 10,000 oocysts/0.5 kg).

Allergic conjunctivitis and contact lenses: experience with olopatadine hydrochloride 0.1% therapy

OBJECTIVE

The efficacy of Patanol, a topically applied anti-allergic agent, was evaluated in a group of patients with allergic conjunctivitis due to contact lens wear (GROUP I) and a group comprised of seasonal allergic conjunctivitis patients, vernal conjunctivitis patients and atopic keratoconjunctivitis patients (GROUP II).

METHODS

One drop of Patanol was administered to each eye twice daily. Signs and symptoms were assessed 7, 14, and 28 days after initiation of drug therapy.

RESULTS

Itching/burning, tearing, hyperemia and papillary reaction were reduced to scores of 0/1 (absent/mild) in 85%, 90%, 81% and 62%, respectively, of GROUP I patients at Day 28. The allergic conditions in GROUP II patients also improved with Patanol treatment. Itching/burning, tearing, hyperemia and papillary reactions were absent/mild in 60%, 76%, 96% and 90%, respectively, of these patients at Day 28.

CONCLUSION

Patanol treatment effectively and rapidly alleviated the signs and symptoms of allergic conjunctivitis due to contact lens wear as well as vernal conjunctivitis, atopic keratoconjunctivitis and the common seasonal allergic conjunctivitis. Patanol allowed allergic patients to be more comfortable while permitting them to continue using contact lenses.

Localization in artificial disorder: two coupled quantum dots

Using single electron capacitance spectroscopy, we study electron additions in quantum dots containing two potential minima separated by a shallow barrier. Analysis of the addition spectra in the magnetic field allows us to distinguish between electrons delocalized over the entire dot and those localized in either of the potential minima. We demonstrate that a high magnetic field abruptly splits up a low-density droplet into two smaller fragments, each residing in a potential minimum. An unexplained cancellation of electron repulsion between electrons in these fragments gives rise to paired electron additions.

Initial clinical experience with a fully automatic in-hospital external cardioverter defibrillator

Sudden cardiac death due to ventricular tachyarrhythmia remains a significant problem in the in-hospital setting. Although the probability of survival is closely correlated with the rapidity of a response by qualified personnel, response times can be prolonged, even in specialized care units. In an effort to decrease response time, a fully automatic external cardioverter defibrillator was recently devised. This device was evaluated in the in-hospital setting to assess safety and efficacy. A total of 79 patients were studied in a multicenter trial. Patients were monitored with fully functional devices in the electrophysiology laboratory (51 patients) and in the cardiac care unit (28 patients). Performance of the device was assessed by comparing automatic responses to any sustained change in cardiac rhythm, either spontaneous or induced, to a retrospective review of stored ECG data and programmed parameters. During a total duration of 964 hours of monitoring, there were 99 episodes of sustained tachycardia. Therapy was appropriately delivered or advised in all episodes. Therapy was advised in one episode of supraventricular tachycardia. There were no episodes of inappropriate therapy delivery. There were no complications or adverse events. The device performed with a sensitivity of 100% and specificity of 98.8% with an average response time of 22 seconds. In conclusion, this automatic external defibrillator was safe, effective, and functioned as designed. Significant improvement in response time to life-threatening ventricular tachyarrhythmia in the in-hospital setting would be expected if this technology was widely adopted.

Localization-delocalization transition in quantum dots

Single-electron capacitance spectroscopy precisely measures the energies required to add individual electrons to a quantum dot. The spatial extent of electronic wave functions is probed by investigating the dependence of these energies on changes in the dot confining potential. For low electron densities, electrons occupy distinct spatial sites localized within the dot. At higher densities, the electrons become delocalized, and all wave functions are spread over the full dot area. Near the delocalization transition, the last remaining localized states exist at the perimeter of the dot. Unexpectedly, these electrons appear to bind with electrons in the dot center.