Recombinant angiotensin II is an emerging drug therapy for refractory hypotension. Its use is relevant to patients with disruption of the renin–angiotensin–aldosterone system denoted by elevated direct renin levels. We present a child that responded to recombinant angiotensin II in the setting of right ventricular hypertension and multi-organism septic shock.

Heterogeneity in pulmonary microvascular blood flow (perfusion) provides an early indicator of lung disease or disease susceptibility. However, most computational models of the pulmonary vasculature neglect structural heterogeneities, and are thus not accurate predictors of lung function in disease that is not diffuse (spread evenly through the lung). Models that do incorporate structural heterogeneity have either neglected the temporal dynamics of blood flow, or the structure of the smallest blood vessels. Larger than normal oscillations in pulmonary capillary calibre, high oscillatory stress contribute to disease progression. Hence, a model that captures both spatial and temporal heterogeneity in pulmonary perfusion could provide new insights into the early stages of pulmonary vascular disease. Here, we present a model of the pulmonary vasculature, which captures both flow dynamics, and the anatomic structure of the pulmonary blood vessels from the right to left heart including the micro-vasculature. The model is compared to experimental data in normal lungs. We confirm that spatial heterogeneity in pulmonary perfusion is time-dependent, and predict key features of pulmonary hypertensive disease using a simple implementation of increased vascular stiffness.

Objectives: Subjective cognitive decline (SCD), or self-reported cognitive decline despite normal neuropsychological test performance, is a risk factor for objective cognitive decline and Alzheimer’s disease (AD). While brain mechanisms contributing to SCD are not well defined, studies show associations with vascular risk factors and altered cerebral blood flow (CBF), raising the hypothesis that those with SCD might be experiencing vascular dysregulation, or a disruption in the normal relationship between CBF and cognition. We examined whether the association between CBF and verbal memory performance differs between those with SCD (SCD+) and those without SCD (SCD-). Methods: Linear mixed-effects models were used to investigate whether the voxel-wise relationship between arterial spin labeling (ASL) MRI-measured CBF and verbal memory performance was modified by SCD among a group of 70 cognitively normal older adults (35 SCD+, 35 SCD-; mean age=72) matched on age, gender, and symptoms of depression. Results: Results indicated that the SCD- group exhibited positive associations between verbal memory and CBF within the posterior cingulate cortex, middle temporal gyrus, and inferior frontal gyrus, whereas the SCD+ group displayed negative associations between verbal memory and CBF within the posterior cingulate cortex, middle temporal gyrus, hippocampus, fusiform gyrus, and inferior frontal gyrus. Conclusions: Findings suggest that, while higher CBF is supportive of memory function in those without SCD, higher CBF may no longer support memory function in those presenting with SCD, perhaps reflecting neurovascular dysregulation. (JINS, 2018, 24, 213–223)

Both perfusion SPECT and FDG-PET provide images that closely reflect neuronal activity. There is a characteristic regional impairment in Alzheimer's disease (AD) that involves mainly the temporo-parietal association cortices, mesial temporal structures and to a more variable degree also the frontal association cortex. This pattern of functional impairment can provide a biomarker for diagnosis of AD and other neurodegenerative dementias at the clinical stage of mild cognitive impairment, and for monitoring of progression. FDG-PET is quantitatively more accurate and thus better suited to multicenter studies than perfusion SPECT. Regional metabolic and blood flow changes are closely related to clinical symptoms, and most areas involved in these changes will also develop significant cortical atrophy. FDG-PET is complementary to amyloid PET, which targets a molecular marker that does not have a close relation to current symptoms. Current restrictions in the availability and cost of FDG-PET are being reduced, as oncological FDG-PET is being adopted as a standard clinical service in most countries. Limitations in the availability of trained staff should be overcome by training programs set up by professional organizations. Against the background of the development of new criteria for diagnosing AD before the onset of dementia, FDG-PET is expected to play an increasing role in diagnosing patients at an early stage of AD and in clinical trials of drugs aimed at preventing or delaying the onset of dementia.

Background: The aim of this study is to investigate the diagnostic value of perfusion 99mTc-exametazime single photon emission computed tomography (SPECT) in the diagnosis of dementia with Lewy bodies (DLB) and Alzheimer's disease (AD) in comparison with dopaminergic 123I-2β-carbomethoxy-3β-(4-iodophenyl)-n-(3-fluoropropyl) nortropane (FP-CIT) SPECT imaging.

Methods: Subjects underwent 99mTc-exametazime scanning (39 controls, 36 AD, 30 DLB) and 123I-FP-CIT scanning (33 controls, 33 AD, 28 DLB). For each scan, five raters performed visual assessments blind to clinical diagnosis on selected transverse 99mTc-exametazime images in standard stereotactic space. Diagnostic accuracy of 99mTc-exametazime was compared to 123I-FP-CIT results for the clinically relevant subgroups AD and DLB using receiver operating characteristic (ROC) curve analysis.

Results: Inter-rater agreement for categorizing uptake was “moderate” (mean κ = 0.53) for 99mTc-exametazime and “excellent” (mean κ = 0.88) for 123I-FP-CIT. For AD and DLB, consensus rating matched clinical diagnosis in 56% of cases using 99mTc-exametazime and 84% using 123I-FP-CIT. In distinguishing AD from DLB, ROC analysis revealed superior diagnostic accuracy with 123I-FP-CIT (ROC curve area 0.83, sensitivity 78.6%, specificity 87.9%) compared to occipital 99mTc-exametazime (ROC curve area 0.64, sensitivity 64.3%, specificity 63.6%) p = 0.03.

Conclusion: Diagnostic accuracy was superior with 123I-FP-CIT compared to 99mTc-exametazime in the differentiation of DLB from AD.

Congenital heart disease occurs in roughly 0.7% of live-births. Approximately one-half of these defects are severe, requiring surgical correction or palliation. In a large percentage of such procedures in children, moderate or profound hypothermic cardiopulmonary bypass is employed. Because, nowadays, early correction of the defect rather than a palliative procedure is more frequently pursued, the surgeon, anesthesiologist, and perfusionist are called upon to manage younger and smaller children undergoing longer and more complex operations which necessitate longer times on bypass. Due to the particular underlying heart defect, the pathway of flow and viscosity of the blood are frequently different from those encountered in the adult with atherosclerotic coronary arterial or valvar heart disease. Thus, it is important for those caring for children undergoing cardiac surgery utilizing bypass to be well informed about its possible detrimental effects on the various organs. The purpose of this review will be to focus on the effects of bypass on flow to, and metabolism of, the organs and to highlight what is known with regard to these features in children rather than adults.

The advent of cardiopulmonary bypass in 1953, and its subsequent continuous refinements, have securely established the specialty of cardiovascular surgery. In conjunction with the improved methods of myocardial preservation, this has allowed the safe repair of acquired and complex congenital cardiac defects. During the years, the many variables of the systems used for cardiopulmonary bypass have been altered to the point that most operations are now reproducible with, relatively, low morbidity and mortality. Although in its present form the system is quite reasonable for most routine surgery, it is far from perfect. There remains, therefore, a quest for alterations to improve the system as an ongoing process. Certain complications of open-heart surgery persist and many new and unique approaches to the concept of organ protection and the treatment of these complications must be developed and refined.

Excised eyes of the horseshoe crab (Limulus polyphemus) have long provided robust preparations for fundamental studies of the visual neuroscience of photoreceptors. Such preparations are particularly useful for immersion in perfusion chambers whose perfusate can be varied as needed. Little attention has been paid in the past to the osmotic properties of such perfusates because they have generally been virtually isotonic with natural seawater. We here report that (1) some recent Limulus studies have used organ culture perfusates that are severely hypotonic and (2) that that fact has not been adequately disclosed.

Efferents from the brain of Limulus course toward its lateral eye and release octopamine and substance P into it. These neurotransmitters have previously been found to act as neuromodulators in this visual system by altering the size of its responses to light. We report here that both also modulate the timing of the receptor potentials (RPs) evoked by brief light flashes and that these timing effects are temperature dependent. Specifically: We extend our previous report that octopamine prolongs ambient RPs in a categorical fashion and here demonstrate that it does the same at colder temperatures. Categorical means that a given RP is either clearly prolonged in a dramatic fashion or its duration is otherwise unremarkable. Octopamine also accelerates the onsets of RPs when they are evoked by weak flashes under cold temperatures. Contrariwise, substance P accelerates RPs at all temperatures and this acceleration dramatically reduces the sluggishness that is otherwise typically present at low temperatures. Quantitative analysis of intensity-response functions also demonstrated that light sensitivity under substance P is significantly augmented. The plain temporal antagonism between these two modulators demonstrates that the visual system of Limulus possesses a well-poised mechanism which could be used to adjust the timing of its neural processing to interface well with the temporal characteristics of those visual stimuli that are currently present.

Low-frequency hearing impairment (LFHI) is mainly attributed to endolymphatic hydrops and has a great variety of possible outcomes. At present, no conservative therapeutic regimen has proven to be ‘gold-standard’, and information about the prognostic indicators of LFHI is scarce.

In a retrospective investigation, we evaluated the records of 90 patients who had been treated with infusions improving blood perfusion. In patients lacking complete remission, dehydration infusion therapy was added. We also undertook audiometric follow up. We calculated the outcomes after infusion therapy, dehydration therapy and after long-time hearing follow up, and we determined the prognostic relevance of several parameters of anamnesis and clinical examination to outcomes, for both therapeutic interventions and long-time hearing.

The prognosis of LFHI was significantly correlated to certain anamnestic and clinical parameters; a short duration of the disease, lack of vertigo and female gender implied a better outcome. The pretherapeutic hearing threshold was an important prognostic factor; the outcome was significantly worse in patients with distinct hearing impairment in low or high frequencies, compared with that in patients with little hearing loss. Whereas vertigo was a negative prognostic factor, the results of quantitative vestibular testing were irrelevant to the outcome. The glycerol test failed to predict the effectiveness of dehydration therapy and lacked any value in predicting prognosis.

These results allow the clinician to focus the anamnesis and diagnostic examination on prognostically relevant parameters, thus enabling a better estimation of the long-term disease course and improved counselling of patients. Furthermore, these results help to distinguish valuable from irrelevant diagnostic procedures.