Magnetic Dipole Transition in

The magnetic dipole transition strength B(M1) of ^{48}Ca is dominated by a single resonant state at an excitation energy of 10.23 MeV. Experiments disagree about B(M1) and this impacts our understanding of spin flips in nuclei. We performed ab initio computations based on chiral effective field theory and found that B(M1: 0^{+}→1^{+}) lies in the range from 7.0 to 10.2 µ_{N}^{2}. This is consistent with a (γ,n) experiment but larger than results from (e,e^{'}) and (p,p^{'}) scattering. Two-body currents yield no quenching of the B(M1) strength and continuum effects reduce it by about 10%. For a validation of our approach, we computed magnetic moments in ^{47,49}Ca and performed benchmark calculations in light nuclei.

Isomeric Excitation Energy for

The excitation energy of the 1/2^{-} isomer in ^{99}In at N=50 is measured to be 671(37) keV and the mass uncertainty of the 9/2^{+} ground state is significantly reduced using the ISOLTRAP mass spectrometer at ISOLDE/CERN. The measurements exploit a major improvement in the resolution of the multireflection time-of-flight mass spectrometer. The results reveal an intriguing constancy of the 1/2^{-} isomer excitation energies in neutron-deficient indium that persists down to the N=50 shell closure, even when all neutrons are removed from the valence shell. This trend is used to test large-scale shell model, ab initio, and density functional theory calculations. The models have difficulties describing both the isomer excitation energies and ground-state electromagnetic moments along the indium chain.

Observation of the Exotic 0_{2}

We report here the first observation of the 0_{2}^{+} state of ^{8}He, which has been predicted to feature the condensatelike α+^{2}n+^{2}n cluster structure. We show that this state is characterized by a spin parity of 0^{+}, a large isoscalar monopole transition strength, and the emission of a strongly correlated neutron pair, in line with theoretical predictions. Our finding is further supported by the state-of-the-art microscopic α+4n model calculations. The present results may lead to new insights into clustering in neutron-rich nuclear systems and the pair correlation and condensation in quantum many-body systems under strong interactions.

Proton Distribution Radii of

The root mean square radii of the proton density distribution in ^{16-24}O derived from measurements of charge changing cross sections with a carbon target at ∼900A MeV together with the matter radii portray thick neutron skin for ^{22-24}O despite ^{22,24}O being doubly magic. Imprints of the shell closures at N=14 and 16 are reflected in local minima of their proton radii that provide evidence for the tensor interaction causing them. The radii agree with ab initio calculations employing the chiral NNLO_{sat} interaction, though skin thickness predictions are challenged. Shell model predictions agree well with the data.

Ab Initio Structure Factors for Spin-Dependent Dark Matter Direct Detection.

We present converged ab initio calculations of structure factors for elastic spin-dependent WIMP scattering off all nuclei used in dark matter direct-detection searches: ^{19}F, ^{23}Na, ^{27}Al, ^{29}Si, ^{73}Ge, ^{127}I, and ^{129,131}Xe. From a set of established two- and three-nucleon interactions derived within chiral effective field theory, we construct consistent WIMP-nucleon currents at the one-body level, including effects from axial-vector two-body currents. We then apply the in-medium similarity renormalization group to construct effective valence-space Hamiltonians and consistently transformed operators of nuclear responses. Combining the recent advances of natural orbitals with three-nucleon forces expressed in large spaces, we obtain basis-space converged structure factors even in heavy nuclei. Generally results are consistent with previous calculations but large uncertainties in ^{127}I highlight the need for further study.

Extracorporeal membrane oxygenation (ECMO) in patients with COVID-19: a rapid systematic review of case studies.

OBJECTIVE: COVID-19 can cause severe acute respiratory distress syndrome (ARDS). Extracorporeal membrane oxygenation (ECMO) can support gas exchange in patients failing conventional mechanical ventilation, but its role is still controversial. We performed a rapid systematic review focusing on the use of ECMO in patients with COVID-19. MATERIALS AND METHODS: PubMed/MEDLINE, Google Scholar, Embase, the Cochrane Library, EBSCO and Ovid (updated 30 April 2020) were systematically searched. Case reports/Case series from COVID-19 patients treated with ECMO were included in the study. Three reviewers assessed, selected, and abstracted data from studies. All disparate opinions were resolved through discussion. RESULTS: We included 13 articles for systematic evaluation, including 10 case reports and 3 case series studies, with a total of 72 patients. We search for the following information: First author of articles; Patient's location; age; gender; body mass index (BMI); Comorbidities; Time on ECMO; Mode of ECMO; treatments and clinical outcomes. As of all reporting times, our data show that 38 patients (52.8%) have died definitively, 13 patients (18.0%) were still receiving ECMO treatment, 12 patients (16.7%) were alive, 7 patients (9.7%) were recovery and 2 cases (2.8%) remained hospitalized. CONCLUSIONS: ECMO plays an important role in the stabilization and survival critically ill patients with COVID-19, but the usefulness of ECMO in reducing the mortality of severe ARDS caused by COVID-19 was limited. Therefore, a larger sample size study and a comprehensive analysis of evaluating the medical value of using ECMO on COVID-19 patients are urgently required.

MiR-25 overexpression promotes fracture healing by activating the Wnt signaling pathway.

OBJECTIVE: To study the mechanism of micro-ribonucleic acid (miR)-25 in regulating the fracture healing in rats. MATERIALS AND METHODS: A total of 45 male Sprague-Dawley (SD) rats were selected and randomly divided into group A [Phosphate Buffered Saline (PBS), n=15], group B (mimics NC, n=15) and group C (miR-25 mimics, n=15). The fracture model in rats was established via operation in all groups. From 1 d after the successful modeling, 50 µL (2 nmoL) of PBS was intraperitoneally injected into rats in group A, an equal amount of mimics NC was injected into rats in group B, and an equal amount of miR-25 mimics was injected into rats in group C. The above agents were injected once a week for consecutive 6 weeks. Fracture healing in rats was evaluated via X-ray imaging. At the same time, miR-25 expression in the three groups was detected via Reverse Transcription-Polymerase Chain Reaction (RT-PCR). Protein expressions of ß-catenin, proliferating cell nuclear antigen (PCNA) and bone morphogenetic protein-2 (BMP-2) in the three groups were detected via Western blotting. The OCN-, PCNA- and BMP-2-positive osteoblasts in the three groups were detected via immunohistochemical staining and were further quantified. Moreover, the biomechanical properties of femoral fracture healing in the three groups were analyzed via the 4-point bending flexural test. RESULTS: The X-ray examination of the femoral fracture healing at postoperative 1 and 7 weeks revealed that the fracture line disappeared, and both callus formation and fracture healing were good in miR-25 mimics group. In PBS group and mimics NC group, a few fracture lines could be observed, and both callus formation and fracture healing were poor. RT-PCR data showed that the expression level of miR-25 significantly increased in the miR-25 mimics group compared with that in the other two groups, and the differences were statistically significant (p<0.01). Western blotting analyses showed upregulated levels of ß-catenin, PCNA and BMP-2 in the miR-25 mimics group compared with those in the control group, and the differences were statistically significant (p<0.01). Immunohistochemical staining manifested that the numbers of OCN-, PCNA- and BMP-2-positive osteoblasts in miR-25 mimics group markedly increased compared with that in the other two groups (p<0.01), suggesting that osteoblast differentiation in miR-25 mimics group was affected. The above immunohistochemical results indicated that the osteoblast differentiation at the fracture end in miR-25 mimics group was markedly enhanced compared with that in control groups. The results of the biomechanical test of femur specimens at 7 weeks after operation showed that in miR-25 mimics group, the maximum load, fracture energy and stiffness increased by 188%, 333% and 90%, respectively, compared with those in the PBS group (p<0.01). It is indicated that miR-25 promoted the mechanical properties of fracture healing. CONCLUSIONS: The overexpression of miR-25 in the fracture in rats promotes fracture healing by activating the Wnt signaling pathway.

Effects of ovarian ablation or suppression in premenopausal breast cancer: A meta-analysis of randomized controlled trials.

BACKGROUND: The effect of ovarian ablation or suppression (OAS) in premenopausal women with breast cancer is controversial. The overall survival (OS), disease-free survival (DFS) and adverse event of OAS versus no OAS were compared. METHODS: A literature review of EMBASE, Web of Science, PUBMED, and Cochrane Library was conducted. The hazard ratio (HR) and 95% confidence interval (CI) for OS and DFS, as well as risk ratio (RR) and 95% CI for adverse events were evaluated. I-squared statistic (I2) represents heterogeneity. RESULTS: Twenty-nine studies with a total of 21,249 women were included. In premenopausal women aged 40 years or younger, there were significant differences in OS (HR 0.78, 95% CI: 0.66-0.94, P=0.008, I2 = 0%) and DFS (HR 0.84, 95% CI: 0.73-0.97, P=0.02, I2 = 0%) between OAS and no OAS. In advanced stage breast cancer, a significant difference was found in OS (HR 0.76, 95% CI: 0.60-0.96, P=0.02, I2 = 0%). Patients treated with OAS had more chances to have hot flushes (RR 1.91, 95% CI: 1.62-2.26, P < 0.01, I2 = 0%) and vaginal dryness (RR 1.19, 95% CI: 1.08-1.31, P=0.0003, I2 = 0%). No significant difference in depression (RR 1.28, 95% CI: 0.94-1.74, P=0.12, I2 = 0%). CONCLUSIONS: The study shows that OAS plays a beneficial role in premenopausal women aged 40 years or younger and advanced stage breast cancer. However, OAS is associated with increase in hot flushes and vaginal dryness.

Prognostic factors associated with mortality before and during anti-tuberculosis treatment.

OBJECTIVE: To identify factors associated with death before the start of anti-tuberculosis treatment, and early and late during treatment, among adult Taiwanese with culture-positive pulmonary tuberculosis (PTB). METHOD: All adult culture-positive PTB patients in Taipei, Taiwan, were included in a retrospective cohort study in 2005-2010. RESULTS: Of 4438 patients (mean age 64.6 years, 70.6% male), 76.8% were successfully treated, 5.4% died before start of treatment, 9.0% died within 8 weeks of treatment initiation and 8.8% died >8 weeks after treatment initiation. After controlling for potential confounders, age ≥ 65 years and male sex were associated with higher risks of death at all time periods investigated. High school education or higher reduced the risk of death before the start of and during treatment, while unemployment increased the risk of mortality during treatment. Cavity on chest X-ray and positivity for acid-fast bacilli were associated with lower risk of mortality before the start of treatment. CONCLUSION: To lower mortality among adult culture-positive PTB patients, it is imperative for clinicians to maintain high awareness of TB and provide more intensive care early, especially for men, the elderly and people with lower socio-economic status (e.g., the unemployed and less educated).

First Report of Seedling Blight of Watermelon Caused by Acidovorax citrulli Transmitted from Rootstock of Pumpkin in China.

Bacterial fruit blotch (BFB) is a devastating disease caused by Acidovorax citrulli, which was first observed in the United States in 1988 (3). A. citrulli can cause severe infection on a wide range of cucurbits, including watermelon, cantaloupe, and pumpkin. Cotyledon symptoms are brown, angular, necrotic spots or large necrotic lesions. The disease is seedborne, so seeds usually serve as the primary inoculum source for BFB outbreaks (2). In July 2012, seedling blight was observed by local farmers from Anhui province in China on watermelon seedlings grafted to pumpkin rootstocks; lesions were morphologically similar to those caused by A. citrulli. Presence of A. citrulli was detected in symptomatic samples by using species-specific primers BX-L1/BX-S-R2 (1). The seed company claimed seeds of watermelon (cv. Changfeng) were certified free of bacterial fruit blotch, but pumpkin seeds (cv. Kangkuxianfeng-1) had not been tested for A. citrulli. For investigating the inoculum source, the remaining seeds of watermelon (cv. Changfeng) and pumpkin (cv. Kangkuxianfeng-1) for seedling production were collected from the farmer and processed for pathogen extraction as described by Walcott and Gitaitis (2). Two microliters of seed wash was used as template for PCR using primers BX-L1/BX-S-R2 (1). The experiment was conducted three times. A 279-bp DNA fragment was consistently amplified by PCR from seed wash of pumpkin seeds, but not from the seed wash of watermelon seeds. Three Acidovorax-like strains (A1, A2, and A3) were isolated from pumpkin seed wash using TWZ semi-selective medium (0.5% peptone, 0.025% CaCl2, 1% Tween-80, 50 mg/liter berberine, 50 mg/liter cycloheximide, 50 mg/liter 2,3,5-triphenyltetrazolium chloride). PCR was performed on the 16S rDNA gene from isolate strain A1, A2, and A3 (1,492 bp; GenBank Accession Nos. JX875533, JX875534, and JX875535) with primers rp1/fd2 (4), and PCR products were sequenced. Results of sequence analysis showed the sequences of strains A1, A2, and A3 were 99% identical to that of the type strain of A. citrulli AAC00-1 (NC_008752). Pathogencity was confirmed by injection of pumpkin cotyledons with bacterial suspensions of each isolate. Collected pumpkin seeds (n = 100 seeds) and watermelon seeds (n = 100 seeds) were planted in plastic pots containing sterilized field soil at room temperature to detect A. citrulli by a wet chamber growing out test. Eight days later, brown, angular, necrotic spots or wilt developed in pumpkin seedlings, but no symptoms were noted on the watermelon seedlings. To our knowledge, this is the first report of A. citrulli causing watermelon seedling blight transmitted from pumpkin seeds by grafting in China. References: (1) O. Bahar et al. Plant Pathol. 57:754, 2008. (2) R. R. Walcott and R. D. Gitaitis. Plant Dis. 84:470, 2000. (3) G. C. Wall et al. Phytopathology 78:1605, 1988. (4) W. G. Weisburg et al. J. Bacteriol. 173:697, 1991.

Microvascular abnormalities in the bulbar conjunctiva of contact lens users.

Soft contact lenses are commonly used to improve vision acuity or in cosmetic enhancement. We hypothesize that contact lens use can cause inadvertent damage to either the conjunctival microcirculation via direct vasoocclusion when the lens physically interacts with or damages the underlying vessels, or to the bulbar conjunctiva itself when the lens rests unevenly on the surface of the bulbar conjunctiva. Computer-assisted intravital microscopy was utilized to document (via video recording) and objectively quantify (via image analysis) real-time microvascular abnormalities resulting from changes and vessel remodeling in the conjunctival microcirculation in long-term (>2 yrs) contact lens users (n = 102), with non-users serving as control subjects (n = 29). A severity index (SI)--computed as the arithmetic sum of the abnormalities found in the conjunctival microcirculation in each contact lens user--was established for objective comparison with control subjects and critical interpretation. Contact lens user SI was significantly higher than control SI (user = 6.21 ± 1.26; control = 2.31 ± 1.49; p < 0.05), indicative of severe vasculopathy arising from contact lens use. The users also had significantly wider conjunctival vessel diameter (user = 71.25 ± 12.09 µm; control = 52.20 ± 5.10 µm; p < 0.05). Additional abnormalities, including damaged vessels, hemosiderin deposits (from damaged vessels or injury to the surface of the bulbar conjunctiva), vessel sludging, intermittent blood flow, and vessel tortuosity were commonly found in or adjacent to locations where the contact lens physically rested on the underlying conjunctival vessels. These results strongly suggest that microvascular abnormalities and remodeling changes occurred as a result of the inadvertent physical interaction of the lenses with either the underlying conjunctival vessels or the surface of the bulbar conjunctiva in contact lens users.

DOT associated with reduced all-cause mortality among tuberculosis patients in Taipei, Taiwan, 2006-2008.

OBJECTIVE: To determine whether patients receiving directly observed treatment (DOT) had lower all-cause mortality than those treated with self-administered treatment (SAT) and to identify factors associated with mortality among tuberculosis (TB) patients. DESIGN: All TB patients in Taipei, Taiwan, diagnosed between 2006 and 2008 were included in a retrospective cohort study. RESULTS: Among 3624 TB patients, 45.5% received DOT, which was disproportionately offered to older patients and those with more underlying illness and severe TB disease. After controlling for patients' sociodemographic factors, clinical findings and underlying comorbidities, the odds of death were 40% lower (aOR 0.60, 95%CI 0.5-0.8) among patients treated with DOT than those on SAT. After adjusting for DOT, independent predictors of death included non-Taiwan birth, increasing age, male, unemployment, end-stage renal disease requiring dialysis, malignancy, acid-fast bacilli smear positivity and pleural effusion. CONCLUSION: DOT was associated with lower all-cause mortality after controlling for confounding factors. DOT should be expanded in Taiwan to improve critical treatment outcomes among TB patients.

A global emerging disease of Klebsiella pneumoniae liver abscess: is serotype K1 an important factor for complicated endophthalmitis?

BACKGROUND AND AIMS: Over the past two decades in Taiwan, pyogenic liver abscess has usually been caused by a single microorganism, Klebsiella pneumoniae, and is frequently associated with the serious complication of endophthalmitis, especially in diabetic patients. However, the relationship between the clinical presentation and bacterial factors remains unclear. The aim of this study was to investigate the clinical features of patients and the serotype and ribotype of K pneumoniae liver abscess. METHODS: From July 1991 to June 1998, a total of 134 cases of K pneumoniae liver abscess with 248 K pneumoniae isolates from the same patients were collected from two large medical centres in northern Taiwan. Clinical data were collected from medical records. Serotyping and ribotyping were performed using the countercurrent immunoelectrophoresis method and automated Riboprinter. RESULTS: Serotyping revealed that the most common serotypes were K1 (63.4%) and K2 (14.2%). K1 isolates occurred at a significantly higher frequency (p<0.01) than all other serotypes. Among 134 patients, 105 (78.4%) had suffered from diabetes mellitus for 3-15 years. Fourteen patients (10.4%) had metastatic infection to the eye causing septic endophthalmitis. Liver aspirates, and blood and vitreous pus cultures yielded the same serotype of K pneumoniae in all patients. Among patients with septic endophthalmitis, 92.3% (13/14) were diabetic, and 85.7% (12/14) of the isolates belonged to serotype K1. For molecular typing, different degrees of genetic polymorphism among isolates with the same K1 serotype suggested no particular prevalence of any one strain in K pneumoniae liver abscess. CONCLUSION: K pneumoniae serotype K1 was significantly associated with liver abscess and the complication of endophthalmitis, especially in diabetic patients. Physicians should request an immediate report of serotyping and susceptibility test results simultaneously if a diagnosis of pyogenic liver abscess has been made so that early and appropriate management for possible complications will not be delayed. The use of ceftriaxone because of its higher concentration in the aqueous humor is suggested to decrease the chance of septic endophthalmitis.

Real-time interactive coronary MRA.

An interactive real-time imaging system capable of rapid coronary artery imaging is described. High-resolution spiral and circular echo planar trajectories were used to achieve 0.8 x 1.6 mm2 resolution in 135 ms (CEPI) or 1.13 x 1.13 mm2 resolution in 189 ms (spirals), over a 20-cm FOV. Using a sliding window reconstruction, display rates of up to 37 images/sec were achieved. Initial results indicate this technique can perform as a high-quality 2D coronary localizer and with SNR improvement may enable rapid screening of the coronary tree.

Rapid evaluation of left ventricular volume and mass without breath-holding using real-time interactive cardiac magnetic resonance imaging system.

OBJECTIVES: The purpose of this study was to validate cardiac measurements derived from real-time cardiac magnetic resonance imaging (MRI) as compared with well-validated conventional cine MRI. BACKGROUND: Although cardiac MRI provides accurate assessment of left ventricular (LV) volume and mass, most techniques have been relatively slow and required electrocardiogram (ECG) gating over many heart beats. A newly developed real-time MRI system allows continuous real-time dynamic acquisition and display without cardiac gating or breath-holding. METHODS: Fourteen healthy volunteers and nine patients with heart failure underwent real-time and cine MRI in the standard short-axis orientation with a 1.5T MRI scanner. Nonbreath-holding cine MRI was performed with ECG gating and respiratory compensation. Left ventricular end-diastolic volume (LVEDV), left ventricular endsystolic volume (LVESV), ejection fraction (EF) and LV mass calculated from the images obtained by real-time MRI were compared to those obtained by cine MRI. RESULTS: The total study time including localization for real-time MRI was significantly shorter than cine MRI (8.6 +/- 2.3 vs. 24.7 +/- 3.5 min, p < 0.001). Both imaging techniques yielded good quality images allowing cardiac measurements. The measurements of LVEDV, LVESV, EF and LV mass obtained with real-time MRI showed close correlation with those obtained with cine MRI (LVEDV: r = 0.985, p < 0.001; LVESV: r = 0.994, p < 0.001; EF: r = 0.975, p < 0.001; LV mass: r = 0.977, p < 0.001). CONCLUSIONS: Real-time MRI provides accurate measurements of LV volume and mass in a time-efficient manner with respect to image acquisition.

Bacteremia in renal transplant recipients: retrospective analysis of 60 episodes in a teaching hospital.

BACKGROUND: Bacteremia is a major cause of death in renal transplant recipients. However, an understanding of the clinical spectrum of bacteremia post kidney transplantation in Taiwan is lacking. This study was undertaken in an attempt to analyze the causative organisms, the sites of primary infection, and the possible significant determinants of mortality. METHODS: Eighty-six positive blood cultures from renal transplant recipients were seen at the Taichung Veterans General Hospital from August 1993 to April 1999. Sixty blood cultures obtained from episodes that occurred in 43 kidney recipients were regarded as significant and included. All the data were obtained by reviewing medical records. RESULTS: Forty-six episodes (76.7%) of bacteremia happened 6 months after transplantation. Gram-negative bacilli accounted for 73.3% (44/60) of the cases of bacteremia. Escherichia coli, constituting 26.7% (16/60) of the etiologic agents, was the most common pathogen. In 50.0% of all episodes, urinary tract infection was the main cause of bacteremia. The overall mortality rate in this series was 16.7%. Risk of death seemed higher if bacteremia occurred with a primary site of infection other than the urinary tract (26.7% vs 6.7%) and after methylprednisolone pulse therapy (33.3% vs 12.5%), though both correlations were not statistically significant. CONCLUSIONS: This study may shed light on the empirical therapy and better management needed for treating bacteremia in renal transplant recipients in Taiwan and provide a nidus for further prospective surveys.

Real-time black-blood MRI using spatial presaturation.

A real-time interactive black-blood imaging system is described. Rapid blood suppression is achieved by exciting and dephasing slabs outside the imaging slice before each imaging excitation. Sharp-profiled radio frequency saturation pulses placed close to the imaging slice provide good blood suppression, even in views containing slow through-plane flow. In vivo results indicate that this technique improves endocardial border definition during systole in real-time cardiac wall-motion studies. Phantom and animal results indicate that this technique nearly eliminates flow artifacts in real-time intravascular studies. J. Magn. Reson. Imaging 2001;13:807-812.

Rapid ventricular assessment using real-time interactive multislice MRI.

A multislice real-time imaging technique is described which can provide continuous visualization of the entire left ventricle under resting and stress conditions. Three dynamically adjustable slices containing apical, mid, and base short axis views are imaged 16 times/sec (48 images/sec), with each image providing 3.12 mm resolution over a 20 cm field of view. Initial studies indicate that this technique is useful for the assessment of LV function by providing simultaneous real-time visualization of all 16 wall segments. This technique may also be used for stress LV function and, when used in conjunction with contrast agents, myocardial perfusion imaging. Magn Reson Med 45:371-375, 2001.

Rapid assessment of cardiac anatomy and function with a new hand-carried ultrasound device (OptiGo): a comparison with standard echocardiography.

AIMS: The aim of this study was to evaluate image quality and accuracy of a new hand-carried ultrasound device, OptiGo (Agilent Technologies) when compared to standard echocardiography in the setting of a focused examination in the assessment of cardiac anatomy and function. METHODS AND RESULTS: One-hundred and twenty-one patients were prospectively enrolled. Image quality and accuracy in assessment of chamber sizes, left ventricular (LV) wall thickness and contractility, right ventricular (RV) function, mitral and aortic leaflet thickening, mitral annular calcification, pericardial effusion and valvular regurgitation were assessed. Two-dimensional (2D) findings were graded on a four-point scale, except for LV function (six-point) and valvular leaflet opening (two-point). Colour Doppler assessment of valvular regurgitation was graded on a seven-point scale. A one-point difference was considered minor; a two or more point difference was considered major. There was no statistically significant difference in image quality between the two devices. For 2D data, the number of total (minor and major) differences between the hand-carried and standard echocardiograph examinations was significantly greater than the inter-observer variability (14.3% vs 10.7%, P< 0.05), however, major differences alone were not statistically different. For the colour Doppler assessment of regurgitation there was a significant difference between the devices for total (minor and major) differences, (40.0% vs 31.8%,P < 0.007) however, the number of major differences is explained by inter-observer variability. CONCLUSIONS: Image quality and diagnostic accuracy of the hand-carried device, OptiGo, was adequate for the purpose of performing a focused assessment of a limited number of 2D and Doppler parameters for the evaluation of cardiac anatomy and function.

Genetic characterization of rebounding HIV-1 after cessation of highly active antiretroviral therapy.

Despite prolonged treatment with highly active antiretroviral therapy (HAART), infectious HIV-1 continues to replicate and to reside latently in resting memory CD4(+) T lymphocytes, creating a major obstacle to HIV-1 eradication. It is therefore not surprising to observe a prompt viral rebound after discontinuation of HAART. The nature of the rebounding virus, however, remains undefined. We now report on the genetic characterization of rebounding viruses in eight patients in whom plasma viremia was undetectable throughout about 3 years of HAART. Taking advantage of the extensive length polymorphism in HIV-1 env, we found that in five patients who did not show HIV-1 replication during treatment, the rebound virus was identical to those isolated from the latent reservoir. In three other patients, two of whom had been free of plasma viremia but had showed some residual viral replication, the rebound virus was genetically different from the latent reservoir virus, corresponding instead to minor viral variants detected during the course of treatment in lymphoid tissues. We conclude that in cases with apparent complete HIV-1 suppression by HAART, viral rebound after cessation of therapy could have originated from the activation of virus from the latent reservoir. In patients with incomplete suppression by chemotherapy, however, the viral rebound is likely triggered by ongoing, low-level replication of HIV-1, perhaps occurring in lymphoid tissues.