Breathing Behaviour Modification of Gallium MIL-53 Metal-Organic Frameworks Induced by the Bridging Framework Inorganic Anion.

Controlling aspects of the µ2 -X- bridging anion in the metal-organic framework Ga-MIL-53 [GaX(bdc)] (X- =(OH)- or F- , bdc=1, 4-benzenedicarboxylate) is shown to direct the temperature at which thermally induced breathing transitions of this framework occur. In situ single crystal X-ray diffraction studies reveal that substituting 20 % of (OH)- in [Ga(OH)(bdc)] (1) for F- to produce [Ga(OH)0.8 F0.2 (bdc)] (2) stabilises the large pore (lp) form relative to the narrow pore (np) form, causing a well-defined decrease in the onset of the lp to np transition at higher temperatures, and the adsorption/desorption of nitrogen at lower temperatures through np to lp to intermediate (int) pore transitions. These in situ diffraction studies have also yielded a more plausible crystal structure of the int-[GaX(bdc)] ⋅ H2 O phases and shown that increasing the heating rate to a flash heating regime can enable the int-[GaX(bdc)] ⋅ H2 O to lp-[GaX(bdc)] transition to occur at a lower temperature than np-[GaX(bdc)] via an unreported pathway.

Prostate Cancer Diffusion-Weighted Magnetic Resonance Imaging: Does the Choice of Diffusion-Weighting Level Matter?

BACKGROUND: Diffusion-weighted magnetic resonance imaging plays an important role in multiparametric assessment of prostate lesions. The derived apparent diffusion coefficient (ADC) could be a useful quantitative biomarker for malignant growth, but lacks acceptance because of low reproducibility. PURPOSE: To investigate the impact of the choice of diffusion-weighting levels (b-values) on contrast-to-noise ratio and quantitative measures in prostate diffusion-weighted MRI. STUDY TYPE: Retrospective and simulation based on published data. SUBJECTS: Patient cohort (21 men with Prostate Imaging-Reporting and Data System (PI-RADS) version 2 score ≥3) from a single-center study. FIELD STRENGTH/SEQUENCE: 3 T/diffusion-weighted imaging with single-shot echo-planar imaging. ASSESSMENT: Both clinical data and simulations based on previously acquired data were used to quantify the influence of b-value choice in normal peripheral zone (PZ) and PZ tumor lesions. For clinical data, ADC was determined for different combinations of b-values. Contrast-to-noise ratio and quantitative diffusion measures were simulated for a wide range of b-values. STATISTICAL TESTS: Tissue ADC and the lesion-to-normal tissue ADC ratios of different b-value combinations were compared with paired two-tailed Student's t-tests. A P-value <0.05 was considered statistically significant. RESULTS: Findings about b-value dependence derived from clinical data and from simulations agreed with each other. Provided measurement was limited to two b-values, simulation-derived optimal b-value choices coincided with PI-RADSv2 recommendations. For two-point measurements, ADC decreased by 15% when the maximum b-value increased from 1000 to 1500 seconds/mm2 , but corresponding lesion-to-normal tissue ADC ratio showed no significant change (P = 0.86 for acquired data). Simulations with three or more measurement points produced ADCs that declined by only 8% over this range of maximum b-value. Corresponding ADC ratios declined between 2.6% (three points) and 3.8% (21 points). Simulations also revealed an ADC reduction of about 19% with the shorter echo and diffusion time evaluated. DATA CONCLUSION: The comprehensive assessment of b-value dependence permits better formulation of protocol and analysis recommendations for obtaining reproducible results in prostate cancer diffusion-weighted MRI. LEVEL OF EVIDENCE: 4 TECHNICAL EFFICACY: Stage 2.

Acute Disseminated Encephalomyelitis in an Incarcerated Adolescent Presents as Acute Psychosis: Case Report and Literature Review.

OBJECTIVE: We aimed to describe a case of an incarcerated adolescent with acute disseminated encephalomyelitis (ADEM) presenting as acute psychosis. METHODS: This was a retrospective case report followed with chart and literature review. MAIN FINDINGS: An adolescent with ADEM presented with drastic behavior and personality changes that led to her incarceration for serious charges. Acute disseminated encephalomyelitis leads to neuropsychiatric effects and can be seen with magnetic resonance imaging as a large mass effect that may result in a poor prognosis. This adolescent made a full recovery from her left facial droop, slurred speech, and left-sided hemiplegia, and her personality changes were reverted. CONCLUSIONS: Acute disseminated encephalomyelitis can present as acute psychosis; therefore, clinical suspicion is important when treating patients who have a history of past infectious brain diseases, especially encephalitis. Given the rapid onset of disease, physicians must be knowledgeable of the diagnosis and treatment of ADEM and be vigilant in finding organic causes of acute psychosis.

Decreased Diastolic Ventricular Kinetic Energy in Young Patients with Fontan Circulation Demonstrated by Four-Dimensional Cardiac Magnetic Resonance Imaging.

Four-dimensional (4D) flow magnetic resonance imaging (MRI) enables quantification of kinetic energy (KE) in intraventricular blood flow. This provides a novel way to understand the cardiovascular physiology of the Fontan circulation. In this study, we aimed to quantify the KE in functional single ventricles. 4D flow MRI was acquired in eleven patients with Fontan circulation (median age 12 years, range 3-29) and eight healthy volunteers (median age 26 years, range 23-36). Follow-up MRI after surgical or percutaneous intervention was performed in 3 patients. Intraventricular KE was calculated throughout the cardiac cycle and indexed to stroke volume (SV). The systolic/diastolic ratio of KE in Fontan patients was similar to the ratio of the controls' left ventricle (LV) or right ventricle (RV) depending on the patients' ventricular morphology (Cohen´s κ = 1.0). Peak systolic KE/SV did not differ in patients compared to the LV in controls (0.016 ± 0.006 mJ/ml vs 0.020 ± 0.004 mJ/ml, p = 0.09). Peak diastolic KE/SV in Fontan patients was lower than in the LV of the control group (0.028 ± 0.010 mJ/ml vs 0.057 ± 0.011 mJ/ml, p < 0.0001). The KE during diastole showed a plateau in patients with aortopulmonary collaterals. This is to our knowledge the first study that quantifies the intraventricular KE of Fontan patients. KE is dependent on the morphology of the ventricle, and diastolic KE indexed to SV in patients is decreased compared to controls. The lower KE in Fontan patients may be a result of impaired ventricular filling.

Normal Brain and Brain Tumor ADC: Changes Resulting From Variation of Diffusion Time and/or Echo Time in Pulsed-Gradient Spin Echo Diffusion Imaging.

OBJECTIVES: Increasing gradient performance on modern magnetic resonance imaging scanners has profoundly reduced the attainable diffusion and echo times for clinically available pulsed-gradient spin echo (PGSE) sequences. This study investigated how this may impact the measured apparent diffusion coefficient (ADC), which is considered an important diagnostic marker for differentiation between normal and abnormal brain tissue and for therapeutic follow-up. MATERIALS AND METHODS: Diffusion time and echo time dependence of the ADC were evaluated on a high-performance 3 T magnetic resonance imaging scanner. Diffusion PGSE brain scans were performed in 10 healthy volunteers and in 10 brain tumor patients using diffusion times of 16, 40, and 70 ms, echo times of 60, 75, and 104 ms at 3 b-values (0, 100, and 1000 s/mm 2 ), and a maximum gradient amplitude of 68 mT/m. A low gradient performance system was also emulated by reducing the diffusion encoding gradient amplitude to 19 mT/m. In healthy subjects, the ADC was measured in 6 deep gray matter regions and in 6 white matter regions. In patients, the ADC was measured in the solid part of the tumor. RESULTS: With increasing diffusion time, a small but significant ADC increase of up to 2.5% was observed for 6 aggregate deep gray matter structures. With increasing echo time or reduced gradient performance, a small but significant ADC decrease of up to 2.6% was observed for 6 aggregate white matter structures. In tumors, diffusion time-related ADC changes were inconsistent without clear trend. For tumors with diffusivity above 1.0 µm 2 /ms, with prolonged echo time, there was a pronounced ADC increase of up to 12%. Meanwhile, for tumors with diffusivity at or below 1.0 µm 2 /ms, no change or a reduction was observed. Similar results were observed for gradient performance reduction, with an increase of up to 21%. The coefficient of variation determined in repeat experiments was 2.4%. CONCLUSIONS: For PGSE and the explored parameter range, normal tissue ADC changes seem negligible. Meanwhile, observed tumor ADC changes can be relevant if ADC is used as a quantitative biomarker and not merely assessed by visual inspection. This highlights the importance of reporting all pertinent timing parameters in ADC studies and of considering these effects when building scan protocols for use in multicenter investigations.

The time of death's badness.

Those who endorse the view that death is in some cases bad for the deceased--a view that, as I shall explain, has considerable bearing on many bioethical issues--need to address the following, Epicurean question: When is death bad for the one who dies? The two most popular answers are "before death" (priorism) and "after death" (subsequentism). Part of the support for these two views consists in the idea that a third answer, "at no time" (atemporalism), makes death unsatisfyingly different from other evils. I argue that this objection is mistaken, and that priorism and subsequentism face problems that atemporalism avoids. Moreover, I argue that if it is nonetheless insisted that we must find a time at which my death is bad for me, we can appeal to periods that begin before my death and end after my death. I end with some implications for posthumous harm.

Brain diffusion MRI with multiplexed sensitivity encoding for reduced distortion in a pediatric patient population.

BACKGROUND: Diffusion-weighted imaging (DWI) is a valuable tool for routine imaging of the pediatric brain. However, the commonly used single-shot (ss) echo-planar imaging (EPI) DWI sequence is prone to geometric distortions and T2*-blurring. This study aimed to investigate in a pediatric population the benefits of using multiplexed sensitivity-encoding (MUSE) without and with reversed polarity gradients (RPG) instead. METHODS: This retrospective study compared image quality, geometric distortions, and diffusion values between three different approaches for DWI (ssEPI, MUSE, and RPG-MUSE) in 14 patients (median age = 4 (0.6-15) years, 11 males). Distortion levels were quantified and compared in two brain regions, i.e., the brain stem and the temporal lobes, using the Dice Coefficient and the Hausdorff Distance, with T2-weighted images as reference. Expected geometrical distortion was further evaluated by comparing the effective echo spacing between the DWI sequences. Apparent diffusion coefficient (ADC) values were determined in the genu of the corpus callosum and the optic nerves. Two raters graded overall image quality and image distortions on a Likert scale. RESULTS: Distortion levels assessed with Dice coefficient and Hausdorff distance were significantly lower for MUSE (p < 0.05) and RPG-MUSE (p < 0.01) compared to ssEPI. No significant difference in ADC values was observed between methods. The RPG-MUSE method was graded by one rater as significantly higher in overall image quality than ssEPI (p < 0.05) and by both raters as significantly lower in levels of image distortions than both MUSE (p < 0.05) and ssEPI (p < 0.05). These results were in agreement with the reduced effective echo spacing was that was attained with MUSE and RPG-MUSE. CONCLUSION: For imaging of the pediatric brain, MUSE and even more so RPG-MUSE offers both improved geometric fidelity and image quality compared to ssEPI.

Comprehensive echocardiographic imaging of atrioventricular valves in children with atrioventricular septal defect: Accuracy of 2D and 3D imaging and reasons for disagreement.

OBJECTIVE: To compare the accuracy and reasons for disagreement of two-dimensional (2D) and three-dimensional (3D) echocardiography findings in the assessment of the atrioventricular valve complex in patients with atrioventricular septal defect. METHODS: A total of 20 children (mean age 8 months) with atrioventricular septal defect were enrolled prospectively into this study. The accuracy of and the reasons for disagreement in the assessment of the atrioventricular valve features were analyzed between 2D and 3D echocardiography and surgical findings. RESULTS: We found that in assessing the Rastelli type and the extension of the inferior leaflet into the right ventricle, 3D echocardiography was more accurate compared to 2D echocardiography. In all other features, 2D and 3D echocardiography showed similar accuracy. A significant reason for inaccuracy by both echo modalities was that the technique itself could not visualize the feature, although the image quality was considered to be adequate. In most cases, where it was not possible to visualize the atrioventricular feature by 2D, it was possible by 3D, and vice versa. CONCLUSION: The accuracy of 2D and 3D echocardiography and understanding the potential reasons for disagreements in assessing the atrioventricular valve complex with 2D and 3D can guide the use of those two techniques when combining them in the clinical practice.

[Transplantation and donation of tissues--six years with the new law. Experiences from the tissue bank in Lund]. / Transplantation och donation av vävnader--sex år med nya lagen. Erfarenheter från vävnadsbanken i Lund.

Tissue transplantation is more common than organ transplantation. Legislative changes in 1996 transformed tissue banking and conditions for tissue transplantation in Sweden. After an initial decrease in donated tissue, heart valves are now available in sufficient numbers, but there is sometimes a shortage of valves the right size for pediatric cardiac surgery. Since the new transplantation legislation was implemented there has been an increase in the number of valves from neonatal donation and after sudden infant death. The number of donated corneas does not correspond to the number required for transplantation. A number of tissue coordinators have been established throughout the country and recently some new tissue banks were founded to increase the amount of tissue available for transplantation. The organization of the tissue bank in Lund is described. There is a lack of knowledge about tissue transplantation and donation among health professionals as well as the general public, and more education is warranted.

Outcome of surgical commissurotomy for aortic valve stenosis in early infancy.

BACKGROUND: The method of treatment of aortic valve stenosis in early infancy is still controversial. This study was performed to evaluate short-term and long-term outcome in our center during a 14-year period. METHODS: Between 1991 and 2004, 64 consecutive patients younger than 3 months old underwent open surgical commissurotomy because of aortic valve stenosis. Median age was 18 days (range, 1 to 79 days), and median weight was 3.6 kg (range, 1.9 to 6.7 kg). Left ventricular function was good in 44 patients (69%), depressed in 12 (19%), and poor in 8 (12%). The study ended in July 2005. Median follow-up time was 4.1 years (range, 0.4 to 13.6 years). RESULTS: The 30-day mortality was 3 of 64 patients and late mortality was 3 of 61, and the respective mortality in patients younger than 1 month old was 2 of 41 and 2 of 39. There was no early mortality after 1993 and no late mortality after 1999. Thirteen patients required reoperation. Median time to reoperation was 4.3 years (range, 0.2 to 11.3 years) and to aortic valve replacement (7 Ross and 1 homograft) was 6.9 years (range, 1.6 to 9.7 years). At the last follow-up, all had good left ventricular function and 57 of 58 had an ability index of 1. CONCLUSIONS: Surgical commissurotomy for aortic valve stenosis during the first 3 months of life can be done with low mortality and morbidity. The risk for early recurrent stenosis or regurgitation is low, and the need for aortic valve replacement can, in most cases, be delayed until the child is older. The long-term functional ability is excellent.

Heart transplantation across the antibodies against HLA and ABO.

We have intentionally performed heart transplantation in a 5-year-old child, despite the most unfavourable risk factors for patient survival; the presence of high level of antibodies against donor's human leucocyte antigen (HLA) class I/II and blood group antigens. Pretransplant treatment by mycophenolate mofetil, prednisolone, tacrolimus, intravenous immunoglobulin, rituximab, protein-A immunoadsorption (IA) and plasma exchange reduced antibody titres against the donor's lymphocytes from 128 to 16 and against the donor's blood group antigen from 256 to 0. The patient was urgently transplanted with a heart from an ABO incompatible donor (A(1) to O). A standard triple-drug immunosuppressive protocol was used. No hyperacute rejection was seen. Antibodies against the donor's HLA antigens remained at a low level despite three acute rejections. Rising anti-A(1) blood group antibodies preceded the second rejection and were reduced by two blood group-specific IAs and remained at a low level. The patient is doing well despite the persistence of donor-reactive antibodies.