Background
The role of kidney hypoxia is considered pivotal in the progression of chronic kidney disease. A widely used method to assess kidney oxygenation is blood oxygen level dependent ...(BOLD)–magnetic resonance imaging (MRI), but its interpretation remains problematic. The BOLD‐MRI signal is the result of kidney oxygen consumption (a proxy of glomerular filtration) and supply (ie, glomerular perfusion). Therefore, we hypothesized that with pharmacological modulation of kidney blood flow, renal oxygenation, as assessed by BOLD‐MRI, correlates to filtration fraction (ie, glomerular filtration rate/effective renal plasma flow) in healthy humans.
Methods and Results
Eight healthy volunteers were subjected to continuous angiotensin‐II infusion at 0.3, 0.9, and 3.0 ng/kg per minute. At each dose, renal oxygenation and blood flow were assessed using BOLD and phase‐contrast MRI. Subsequently, “gold standard” glomerular filtration rate/effective renal plasma flow measurements were performed under the same conditions. Renal plasma flow decreased dose dependently from 660±146 to 467±103 mL/min per 1.73 m2 (F3, 21=33.3, P<0.001). Glomerular filtration rate decreased from 121±23 to 110±18 mL/min per 1.73 m2 (F1.8, 2.4=6.4, P=0.013). Cortical transverse relaxation rate (R2*; increases in R2* represent decreases in oxygenation) increased by 7.2±3.8% (F3, 21=7.37, P=0.001); medullar R2* did not change. Cortical R2* related to filtration fraction (R2 0.46, P<0.001).
Conclusions
By direct comparison between “gold standard” kidney function measurements and BOLD MRI, we showed that cortical oxygenation measured by BOLD MRI relates poorly to glomerular filtration rate but is associated with filtration fraction. For future studies, there may be a need to include renal plasma flow measurements when employing renal BOLD‐MRI.
Background: Production of polychlorinated biphenyls (PCBs) ended in the United States in the 1970s, but PCBs persist in the environment and are detectable in the blood of approximately 80% of ...Americans over age 50. PCBs decrease dopamine levels in rats and monkeys. Loss of dopamine is the hallmark of Parkinson disease, a neurodegenerative disease. There are no epidemiologic studies of PCBs and neurodegenerative disease. Methods: We conducted a retrospective mortality study of 17,321 PCB-exposed workers to determine whether mortality from Parkinson disease, dementia, and amyotrophic lateral sclerosis was elevated compared with the U.S. population. All workers had a least 90 days employment in 1 of 3 electrical capacitor plants using PCBs from the 1940s to the 1970s. PCB serum levels from a sample of these workers in the 1970s were approximately 10 times the level of community controls. Results: We found no overall excess of Parkinson disease, amyotrophic lateral sclerosis, or dementia in the PCB-exposed cohort (standardized mortality ratios SMRs-1.40, 1.11, and 1.26, respectively, and number of deaths-14, 10, and 28 respectively). However, sex-specific analyses revealed that women had an excess of amyotrophic lateral sclerosis (SMR-2.26; 95% confidence interval CI = 1.08-4.15; 10 deaths). Furthermore, among highly exposed women (defined by a job-exposure matrix), we found an excess of Parkinson disease (SMR-2.95; 95% CI = 1.08-6.42; 6 deaths) and dementia (SMR-2.04; 95% CI = 1.12-3.43; 14 deaths). Conclusions: Our data are limited due to small numbers and reliance on mortality rather than incidence data, but are suggestive of an effect of PCBs on neurodegenerative disease for women. The literature does not offer an explanation for why women would be more affected than men by PCB exposure for these outcomes.
Although Takotsubo cardiomyopathy (TCM) knowledge is increasing, the exact pathophysiology remains unclear. TCM represents 1%–2% of all troponin positive acute coronary syndromes, affects ...predominantly postmenopausal women, and is commonly preceded by exposure to severe physical or emotional stress. Transient wall motion abnormalities mimicking ST-elevation myocardial infarction is expected as well as increase of troponin levels and echocardiography alterations. This case report is about a patient that as far as we know is the first case that shows the use of myocardial perfusion imaging in the acute phase of TCM. In general, the TCM Mayo Clinic diagnostic criteria have been very helpful in the clinical setting. In this specific case, however, the presence of reduced myocardial perfusion in the acute phase combined with increased troponin levels seemed to be in contradiction with the exclusion of obstructive coronary artery disease.
Purpose
Myocardial perfusion imaging (MPI) with
99m
Tc-sestamibi (sestamibi) SPECT and rubidium-82 (
82
Rb) PET both allow for combined assessment of perfusion and left ventricular (LV) function. We ...sought to compare parameters of LV function obtained with both methods using a single dipyridamole stress dose.
Materials and methods
A group of 221 consecutive patients (65.2 ± 10.4 years, 52.9% male) underwent consecutive sestamibi and
82
Rb MPI after a single dipyridamole stress dose. Sestamibi and
82
Rb summed rest (SRS), stress (SSS) and difference (SDS) scores, and LV end-diastolic (EDV) and end-systolic (ESV) volumes and left ventricular ejection fraction (LVEF) were compared.
Results
Bland-Altman analysis showed that with increasing ESV and EDV the difference between the two perfusion tracers increased both at rest and post-stress. The mean difference in EDV and ESV between the two perfusion tracers at rest could both be independently explained by the
82
Rb SDS and the sestamibi SRS. The combined models explained approximately 30% of the variation in these volumes between the two perfusion tracers (R
2
= 0.261,
p
= 0.005; R
2
= 0.296,
p
< 0.001, for EDV and ESV respectively). However, the mean difference in LVEF between sestamibi and
82
Rb showed no significant trend post-stress (R
2
= 0.001,
p
= 0.70) and only a modest linear increase with increasing LVEF values at rest (R
2
= 0.032,
p
= 0.009).
Conclusions
Differences in left ventricular volumes between sestamibi and
82
Rb MPI increase with increasing volumes. However, these differences did only marginally affect LVEF between sestamibi and
82
Rb. In clinical practice these results should be taken into account when comparing functional derived parameters between sestamibi and
82
Rb MPI.
Background
Increased vascular permeability is an early sign of vascular damage and can be measured with the transcapillary escape rate of albumin (TER
alb
). Although TER
alb
has a multi-exponential ...kinetic model, most published TER
alb
data are based on mono-exponential kinetic models with variation in blood sampling schemes. Aim of this posthoc study was to evaluate the influence of variation in blood sampling schemes and the impact of mono- or bi-exponential analyses on the calculation of TER
alb
. Study participants were part of a cross-over intervention study protocol, investigating effects of sodium loading on blood pressure, endothelial surface layer and microcirculation. Multiple blood samples were drawn between 3 and 60 min after injection of radioactive iodide labeled human serum albumin (rHSA).
Results
In total 27 male participants with 54 measurements were included. For all participants the maximum serum radioactivity was reached within 20 min, while 85% of the participants had their maximum serum activity within 10 min. The TER
alb
calculated with the subsequently chosen T
20–60 min
reference scheme (6.19 ± 0.49%/h) was significantly lower compared to the TER
alb
of the T
3–60 min
, T
5–60 min
, and T
max – 60 min
schemes. There was no significant difference between the T
20–60 min
reference scheme and the T
10–60 min
and T
15–60 min
schemes. Bi-exponential kinetic modeling did not result in significant different observations compared to the mono-exponential kinetic analysis.
Conclusions
As there is variation in the timing of the maximum serum radioactivity of rHSA, blood sampling schemes starting before 10 min after administration of rHSA will result in a significant overestimation of TER
alb
. In addition, variation in kinetic modeling did not result in significant changes in TER
alb
. Therefore, we emphasize the need to standardize TER
alb
and for practical and logistical reasons advocate the use of a mono-exponential model with blood sampling starting 20 min after rHSA administration.
The interRAI-Home Care (interRAI-HC) instrument is commonly used in routine care to assess care and service needs, resource utilisation and health outcomes of community dwelling home care clients. ...Potentially, the interRAI-HC can also be used to calculate societal costs in economic evaluations. The purpose of this study was to assess the convergent validity of the interRAI-HC instrument in comparison with the RUD Lite instrument for the calculation of societal costs among care-dependent community dwelling older adults.
A within-subject design was used. Participants were 65 years and older and received professional community care in five countries. The RUD Lite was administered by trained (research) nurses or self-reports within 4 weeks after the interRAI-HC assessment. Agreement between the interRAI-HC and RUD Lite estimates was assessed using Spearman's correlation coefficients. We hypothesised that there was strong correlation (Spearman's ρ > 0.5) between resource utilisation estimates, costs of care estimates and total societal cost estimates derived from both instruments.
Strong correlation was found between RUD Lite and interRAI-HC resource utilisation assessments for eight out of ten resource utilisation items. Total societal costs according to the RUD Lite were statistically significantly lower than according to the interRAI-HC (mean difference €-804, 95 % CI -1340; -269). The correlation between the instruments for total societal costs and all six cost categories was strong.
The interRAI-HC has good convergent validity as compared with the RUD-Lite instrument to estimate societal cost of resource utilisation in community dwelling older adults. Since interRAI-HC assessments are part of routine care in many community care organisations and countries already, this finding may increase the feasibility of performing economic evaluations among community dwelling older adults.
Previous research of maternal depression during pregnancy suggests an association with low birth weight in newborns. Review of these studies reveals predominant comorbidity with premature birth. This ...current study examines antenatal depression and birth weight in term, medically low-risk pregnancies. Maternal physiological and demographic measures were collected as well. In total, 227 pregnant women were recruited to participate in four experimental protocols at Columbia University Medical Center. Results indicate that depressed pregnant women who carry to term had significantly higher heart rates, lower heart rate variability, and gave birth to heavier babies than those of pregnant women who were not depressed. Low income participants had significantly higher levels of depression, as well as significantly higher heart rates and lower heart rate variability, than those in higher income groups. In full-term infants, maternal prenatal depression appears to promote higher birth weight, with elevated maternal heart rate as a likely mediating mechanism.
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