[Analysis of the prevalence of anticoagulant therapy in patients with cognitive disorders and cerebral amyloid angiopathy (CAA)]. / Analyse zur Häufigkeit einer gerinnungshemmenden Medikation bei Patientinnen mit kognitiven Störungen und zerebraler Amyloidangiopathie (CAA).

OBJECTIVES: To investigate the prevalence of coincident anticoagulation in patients with cognitive disorders and possible or probable cerebral amyloid angiopathy (CAA) as well as the relationship between the presence of oral anticoagulation and CAA-specific lesion load. MATERIALS AND METHODS: Patients with subjective cognitive decline (SCD), amnestic and non-amnestic mild cognitive impairment (aMCI/naMCI), Alzheimer's disease (AD), mixed dementia (MD) and vascular dementia (VD) who presented to our outpatient dementia clinic between February 2016 and October 2020 were included in this retrospective analysis. Patients underwent cranial magnetic resonance imaging (MRI). MRI data sets were analyzed regarding the presence of CAA-related MRI biomarkers to determine CAA prevalence. Presence of anticoagulant therapy was determined by chart review. RESULTS: Within the study period, 458 patients (209 male, 249 female, mean age 73.2 ± 9.9 years) with SCD (n = 44), naMCI (n = 40), aMCI (n = 182), AD (n = 120), MD (n = 68) and VD (n = 4) were analyzed. A total of 109 patients (23.8%) were diagnosed with possible or probable CAA. CAA prevalence was highest in aMCI (39.4%) and MD (28.4%). Of patients with possible or probable CAA, 30.3% were under platelet aggregation inhibition, 12.8% were treated with novel oral anticoagulants and 3.7% received phenprocoumon treatment. Regarding the whole study cohort, patients under oral anticoagulation showed more cerebral microbleeds (p = 0.047). There was no relationship between oral anticoagulation therapy and the frequency of cortical superficial siderosis (p = 0.634). CONCLUSION: CAA is a frequent phenomenon in older patients with cognitive disorders. Almost half of CAA patients receive anticoagulant therapy. Oral anticoagulation is associated with a higher number of cortical and subcortical microbleeds.

First Comparison of Retroperitoneal Versus Transperitoneal Robot-Assisted Nephroureterectomy with Bladder Cuff: A Single Center Study.

INTRODUCTION: After recent presentation of the first complete robot-assisted retroperitoneal nephroureterectomy with bladder cuff (RRNU) for patients with upper tract urothelial cancer (UTUC), we aimed to compare this new surgical technique with robot-assisted transperitoneal nephroureterectomy (TRNU) representing the current standard of care. METHODS: Robot-assisted nephroureterectomies (NUs) were retrospectively analyzed and compared based on two groups: transperitoneal versus retroperitoneal approach. Baseline data were collected for patient demographics, tumor characteristics, intra- (EAUiaiC) and postoperative (Clavien-Dindo) complications, and perioperative variables. Tumor characteristics included grade of malignancy, clinical stage, and surgical margin status. Short-term follow-up data including 30-day readmission rates were collected. Statistical analyses were performed assuming a significant p-value of < 0.05. RESULTS: The analysis includes perioperative patient data after proven UTUC of 24 TRNU versus 12 RRNU (mean age: 70 versus 71 years; BMI: 25.9 versus 26.1 kg/m2; CCI score ≥ 4: 83% versus 75%; ASA score ≥ 3: 37% vs 33%). Intraoperative (16.4% vs 0%, p = 0.35) and postoperative (25% vs 12.5%, p = 0.64) complications demonstrated no significant discrepancy. Notably, RRNU demonstrated significantly shorter surgery time (p < 0.05) and length of stay (p < 0.05). There was no significant difference in histopathological tumor characteristics, whereas significantly more lymph nodes were removed through RRNU (11.0±3.3 vs. 6.4±5.1, p < 0.05). Finally, no statistical difference was shown in short-term follow-up. CONCLUSION: We report the first head-to-head comparison between RRNU and TRNU. RRNU proves to be a safe and feasible approach which appears to be non-inferior to TRNU. RRNU expands the spectrum of minimally invasive treatment options, particularly for patients with major previous abdominal surgery.

First completely robot-assisted retroperitoneal nephroureterectomy with bladder cuff: a step-by-step technique.

INTRODUCTION: While various surgical techniques have been reported for open and minimally invasive treatment of upper tract urothelial cancer (UTUC), the procedure of robot-assisted nephroureterectomy (NU) with bladder cuff has never been reported using only retroperitoneum without entering abdominal cavity. We developed a novel port placement and technique allowing to perform robot-assisted NU by a unique retroperitoneal approach. METHODS: Between February and June 2021 patients with history of UTUC were treated by robot-assisted NU completely restricted to retroperitoneal space using a singular trocar placement and a two-step docking without relocation of the surgical robot. Patient characteristics, perioperative outcomes and short-term follow-up were prospectively analyzed. RESULTS: The analysis included five patients [median age: 73 years; BMI: 27.2 kg/m2; Charlson comorbidity index 5]. All five patients had UTUC with a mean tumor size of 3.02 cm (range 0.9-6.0). UTUC was localized to distal ureter in two and to kidney in three cases. No positive surgical margins were noted for all patients with UTUC [1 low-grade and 4 high-grade]. Retroperitoneal lymphadenectomy in three patients did not reveal positive nodes. No intraoperative adverse events exceeding EAUiaiC classification ≥ 2 were observed, while median EBL was 150 ml (IQR 100-250). No patient experienced postoperative complications exceeding Clavien-Dindo classification ≥ 3a. Median hospital stay was 5.4d without any 30-d readmission. CONCLUSION: We demonstrate safety and feasibility of the first entire robot-assisted retroperitoneal nephroureterectomy (RRNU) with bladder cuff. This surgical technique is easily reproducible, while surgical outcomes are similar to other established techniques.

Biomineralization by particle attachment in early animals.

Crystallization by particle attachment (CPA) of amorphous precursors has been demonstrated in modern biomineralized skeletons across a broad phylogenetic range of animals. Precisely the same precursors, hydrated (ACC-H2O) and anhydrous calcium carbonate (ACC), have been observed spectromicroscopically in echinoderms, mollusks, and cnidarians, phyla drawn from the 3 major clades of eumetazoans. Scanning electron microscopy (SEM) here also shows evidence of CPA in tunicate chordates. This is surprising, as species in these clades have no common ancestor that formed a mineralized skeleton and appear to have evolved carbonate biomineralization independently millions of years after their late Neoproterozoic divergence. Here we correlate the occurrence of CPA from ACC precursor particles with nanoparticulate fabric and then use the latter to investigate the antiquity of the former. SEM images of early biominerals from Ediacaran and Cambrian shelly fossils show that these early calcifiers used attachment of ACC particles to form their biominerals. The convergent evolution of biomineral CPA may have been dictated by the same thermodynamics and kinetics as we observe today.

First-time anterior cruciate ligament injury in adolescent female elite athletes: a prospective cohort study to identify modifiable risk factors.

PURPOSE: To identify modifiable biomechanical and neuromuscular anterior cruciate ligament (ACL) injury risk factors for first-time ACL injury in adolescent female elite football and team handball players. METHODS: Adolescent female elite football and handball players with no previous ACL injury participated in the present study. At baseline, players were tested during side-cutting manoeuvres performed in a 3-dimensional motion analysis laboratory with concomitant electromyography (EMG) measurements. Maximal isometric lower limb muscle strength was assessed by handheld dynamometry. Players were prospectively followed for 2 years after baseline testing, and all magnetic resonance imaging (MRI) verified ACL injuries were registered. The effect of 16 risk factor candidates on the relative risk (RR) of ACL injury was estimated using Poisson regression analysis. RESULTS: Ninety players (age 16.9 ± 1.2 years) were included in the analyses. Nine first-time ACL injuries (injury incidence 10.0% (95% confidence interval (CI) 5.4-18.6%)) were registered during the 2-year follow-up period. Four risk factor candidates were significantly associated with the risk of ACL injury: (1) hip flexion angle at initial contact (IC) [RR 0.56, 95% confidence interval (CI) 0.34-0.92], (2) internal knee rotation angle at IC [RR 1.13, 95% CI 1.08-1.19], (3) semitendinosus EMG activity 50 ms prior to IC [RR: 0.62, 95% CI 0.43-0.89], and (4) external hip rotator strength [RR: 0.77, 95% CI 0.66-0.89]. CONCLUSION: Four distinct ACL injury risk factors related to the side-cutting manoeuvre were identified in a population of adolescent female elite football and team handball players with no previous ACL injury. As ACL injury typically occur during side-cutting, intervention programmes to modify these risk factors pose a promising strategy for ACL injury prevention in adolescent female elite football and team handball. LEVEL OF EVIDENCE: II.

[Prognostic and diagnostic value of cerebrospinal fluid analysis in neurodegenerative dementia diseases]. / Prognostischer und differenzialdiagnostischer Stellenwert der Liquordiagnostik bei neurodegenerativen Demenzerkrankungen.

Cerebrospinal fluid (CSF) analysis is an important diagnostic tool in the assessment of dementia. For the differentiation of Alzheimer's disease from other etiologies of dementia syndromes, established biological markers could be helpful to confirm a distinctive neuropathology. Whereas negative CSF findings can rule out the majority of primarily neurodegenerative disorders, overlapping biomarker profiles remain a diagnostic challenge. Therefore, it is important to interpret CSF results within a specific clinical context. Furthermore, atypical CSF data can be challenging and require profound knowledge of preanalytics, biomarker profiles and the broad spectrum of diseases associated with cognitive decline. Beyond the Alzheimer's disease clinical spectrum, current studies aim at investigating CSF biomarkers to better differentiate tauopathies, TDP43(Transactive response DNA binding protein 43 kDa)-proteinopathies and synucleinopathies.

[Criminal behavior in frontotemporal dementia and Alzheimer's disease]. / Delinquentes Verhalten im Rahmen frontotemporaler Demenzen und der Alzheimer-Erkrankung.

Criminal behavior in older people represents a rare phenomenon. Among older criminals there are many first offenders and 75% are men. Dementia poses one possible origin of delinquency in advanced age. It is unclear how often dementia is the actual cause of delinquency in older age. In studies with older criminals the prevalence of dementia was heterogeneous due to methodological study issues. In the course of the disease 50% of patients with frontotemporal dementia and 10% of patients with Alzheimer's disease commit crimes. The neurobiological origin of delinquency in dementia is poorly understood. On the basis of current study results first delinquency in older age can be explained by impairment of social cognition, difficulties in making appropriate emotional contributions and disturbed control of behavior. Affection of frontal and anterior temporal brain structures seem to be of high relevance. As dementia impairs criminal responsibility psychiatrists are confronted with a forensic evaluation of legal culpability of older criminals. Regarding different etiologies of dementia, specific peculiarities need to be considered in a forensic psychiatric assessment. Especially frontotemporal dementia predisposes towards a wide spectrum of criminal behavior whereas patients with Alzheimer's disease predominantly commit crimes due to cognitive impairment. The review summarizes the present knowledge about criminal behavior in the context of dementia.

[Intracerebral hemorrhage under platelet inhibition and oral anticoagulation in patients with cerebral amyloid angiopathy]. / Intrazerebrale Blutungen unter Plättchenaggregationshemmung und oraler Antikoagulation bei Patienten mit zerebraler Amyloidangiopathie.

Oral anticoagulation in patients with cerebral amyloid angiopathy is a therapeutic challenge. The association of cerebral amyloid angiopathy with intracerebral hemorrhage, a high mortality of intracerebral hemorrhage especially under oral anticoagulation and the high risk of recurrent bleeding require a multidisciplinary approach and a thorough risk-benefit analysis. Vitamin K antagonists increase the risk of intracerebral bleeding and the accompanying mortality by 60% and should be avoided if possible or reserved for special clinical situations (e.g. mechanical aortic valve replacement). Treatment with novel oral anticoagulants and antiplatelet drugs also increases the risk of cerebral bleeding and therefore needs a thorough risk-benefit evaluation. An interventional left atrial appendage closure is a promising therapeutic option especially in patients with an absolute arrythmia with atrial fibrillation. Furthermore, other clinical implications in patients with cerebral amyloid angiopathy are the subject of this review of the literature, such as special characteristics after acute ischemic stroke and the necessary secondary prophylaxis, with previous intracerebral hemorrhage and in patients with cognitive deficits.

Perioperative Management of Gastric Cancer Patients Treated With (Sub)Total Gastrectomy, Cytoreductive Surgery, and Hyperthermic Intraperitoneal Chemotherapy (HIPEC): Lessons Learned.

BACKGROUND: The PERISCOPE I study was designed to assess the safety and feasibility of (sub)total gastrectomy, cytoreductive surgery (CRS), and hyperthermic intraperitoneal chemotherapy (HIPEC) with oxaliplatin and docetaxel for gastric cancer patients who have limited peritoneal dissemination. The current analysis investigated changes in perioperative management together with their impact on postoperative outcomes. METHODS: Patients with resectable gastric cancer and limited peritoneal dissemination were administered (sub)total gastrectomy, CRS, and HIPEC with oxaliplatin (460 mg/m2) and docetaxel (escalating scheme: 0, 50, 75 mg/m2). Of the 25 patients who completed the study protocol, 14 were treated in the dose-escalation cohort and 11 were treated in the expansion cohort (to optimize perioperative management). RESULTS: A significant proportion of the patients in the dose-escalation cohort (n = 7, 50%) had ileus-related complications. In this cohort, enteral nutrition was started immediately after surgery at 20 ml/h, which was increased on day 1 to meet nutritional needs. In the expansion cohort, enteral nutrition was administered at 10 ml/h until day 3, then restricted to 20 ml/h until day 6, supplemented with total parenteral nutrition to meet nutritional needs. Ileus-related complications occurred for two patients (18%) of the expansion cohort. The intensive care unit (ICU) readmission rate decreased from 50 (n = 7) to 9% (n = 1; p = 0.04). CONCLUSION: The implementation of a strict nutritional protocol during the PERISCOPE I study was associated with a decrease in postoperative complications. Based on these results, a perioperative care path was described for the gastric cancer HIPEC patients in the PERISCOPE II study.

Robot-assisted simple prostatectomy versus open simple prostatectomy: a single-center comparison.

PURPOSE: Open simple prostatectomy (OSP) is a standard surgical technique for patients with benign prostatic hyperplasia with prostate size larger than 80 ml. As a minimally invasive approach, robot-assisted simple prostatectomy (RASP) emerged as a feasible surgical alternative. Currently, there are no definite recommendations for the standard use of RASP. Therefore, we aimed at investigating various clinical outcomes comparing RASP with OSP. METHODS: In this retrospective single-center study, we evaluated clinical data from 103 RASP and 31 OSP patients. Both cohorts were compared regarding different clinical characteristics with and without propensity score matching. To detect independent predictive factors for clinical outcomes, multivariate logistic regression analysis was performed. RESULTS: Robot-assisted simple prostatectomy patients demonstrated a lower estimated blood loss and need for postoperative blood transfusions as well as less postoperative complications. OSP had a shorter operative time (125 min vs. 182 min) longer hospital stay (11 days vs. 9 days) and longer time to catheter removal (8 days vs. 6 days). In the multivariate analysis, RASP was identified as an independent predictor for longer operative time, lower estimated blood loss, shorter length of hospital stay, shorter time to catheter removal, less postoperative complications and blood transfusions. CONCLUSION: Robot-assisted simple prostatectomy is a safe alternative to OSP with less perioperative and postoperative morbidity. Whether OSP (shorter operative time) or RASP (shorter length of hospital stay) has a more favorable economic impact depends on the particular conditions of different health care systems. Further prospective comparative research is warranted to define the value of RASP in the current surgical management of benign prostatic hyperplasia.

Detection of pulsed blood flow through a molar pulp chamber and surrounding tissue in vitro.

OBJECTIVES: Due to severe limitations of dental pulp sensitivity tests, the direct recording of pulsed blood flow, using photoplethysmography (PPG), has been proposed. In vivo evaluation is methodologically difficult and in vitro models have hitherto been adversely influenced by shortcomings in emulating the in vivo situation. Consequently, the aim of this study was to test an improved data acquisition system and to use this configuration for recording pulsed blood in a new model. MATERIALS AND METHODS: We introduced a PPG signal detection system by recording signals under different blood flow conditions at two wavelengths (625 and 940 nm). Pulsed blood flow signals were measured using an in vitro model, containing a molar with a glass pulp and a resin socket, which closely resembled in vivo conditions with regard to volumetric blood flow, pulp anatomy, and surrounding tissue. RESULTS: The detection system showed improved signal strength without stronger blanketing of noise. On the tooth surface, it was possible to detect signals emanating from pulsed blood flow from the glass pulp and from surrounding tissue at 625 nm. At 940 nm, pulp derived signals were recorded, without interference signals from surrounding tissue. CONCLUSION: The PPG-based method has the potential to detect pulsed blood flow in small volumes in the pulp and (at 625 nm) also in adjacent tissues. CLINICAL RELEVANCE: The results show the need for clear differentiation of the spatial origins of blood flow signals of any vitality test method to be applied to teeth.

Rasagiline improves polysomnographic sleep parameters in patients with Parkinson's disease: a double-blind, baseline-controlled trial.

BACKGROUND AND PURPOSE: The aim was to study the effects of rasagiline on sleep quality in patients with Parkinson's disease (PD) with sleep disturbances. Sleep disorders are common in PD. Rasagiline is widely used in patients with PD, but double-blind polysomnographic trials on its effects on sleep disturbances are missing. METHODS: This was a single-center, double-blind, baseline-controlled investigator-initiated clinical trial of rasagiline (1 mg/day) over 8 weeks in patients with PD with sleep disturbances. Blinding was achieved by running a strategic matched placebo parallel group. Co-primary outcome measures were the changes between baseline and end of the treatment period in sleep maintenance/efficiency as assessed by polysomnography and the Parkinson's Disease Sleep Scale Version 2 (PDSS-2) score. RESULTS: A total of 20 of 30 patients were randomized to rasagiline (mean ± SD age, 69.9 ± 6.9 years; 10 male; Hoehn-Yahr stage, 1.9 ± 0.8). Compared with baseline, sleep maintenance was significantly increased at the end of the treatment period (relative change normalized to baseline, +16.3 ± 27.9%; P = 0.024, paired two-sided t-test) and a positive trend for sleep efficiency was detected (+12.1 ± 28.6%; P = 0.097). Treatment with rasagiline led to significantly decreased wake time after sleep onset, number of arousals, percentage of light sleep and improved daytime sleepiness as measured by the Epworth Sleepiness Scale. We did not observe changes in the co-primary endpoint PDSS-2 score, and no correlations of polysomnographic sleep parameters or PDSS-2 score with motor function (Unified Parkinson's Disease Rating Scale motor score). Rasagiline was well tolerated with no unexpected adverse events. CONCLUSIONS: In patients with PD with sleep disturbances, rasagiline showed beneficial effects on sleep quality as measured by polysomnography. These effects were probably not related to motor improvement or translated into improved overall sleep quality perception by patients.

Sleep spindles in bipolar disorder - a comparison to healthy control subjects.

OBJECTIVE: Bipolar disorder is a severe mental disorder for which currently no reliable biomarkers exist. It has been shown that patients with schizophrenia but not with unipolar depression have a reduced density of fast sleep spindles during N2 sleep. The aim of this study was to assess fast sleep spindle density in euthymic patients with bipolar disorder. METHODS: Patients with bipolar disorder (n = 24) and healthy control subjects (n = 25) were assessed using all-night polysomnography. Sleep spindles within stage N2 sleep were identified by visual inspection and subdivided into fast (>13 Hz) and slow (≤13 Hz) spindles. All spindles were subsequently characterised by density, frequency, amplitude, duration and coherence. RESULTS: Euthymic patients with bipolar disorder were found to have a reduced density and a lower mean frequency of fast spindles. Slow spindle density and frequency did not differ between groups. There were no differences regarding amplitude, duration or coherence. CONCLUSIONS: A reduction in fast spindle density during N2 sleep points towards thalamic dysfunction as a potential neurobiological mechanism of relevance in bipolar disorder. In addition, a reduced sleep spindle density could be interpreted as a common endophenotype shared with schizophrenia but not unipolar depression and may - if replicated - be of utility in early recognition and risk stratification.

Factors affecting pain relief in response to physical exercise interventions among healthcare workers.

The aim of this study is to identify factors associated with musculo-skeletal pain reduction during workplace-based or home-based physical exercise interventions among healthcare workers. Two hundred female healthcare workers (age: 42.0, BMI: 24.1, average pain intensity: 3.1 on a scale of 0-10) from three hospitals participated. Participants were randomly allocated at the cluster level (18 departments) to 10 weeks of (i) workplace physical exercise (WORK) performed in groups during working hours for 5 × 10 minutes per week and up to five group-based coaching sessions on motivation for regular physical exercise, or (ii) home-based physical exercise (HOME) performed alone during leisure-time for 5 × 10 minutes per week. Linear mixed models accounting for cluster identified factors affecting pain reduction. On average 2.2 (SD: 1.1) and 1.0 (SD: 1.2) training sessions were performed per week in WORK and HOME, respectively. The multi-adjusted analysis showed a significant effect on pain reduction of both training adherence (P=.04) and intervention group (P=.04) with participants in WORK experiencing greater reductions compared with HOME. Obesity at baseline was associated with better outcome. Leisure-time exercise, daily patient transfer, age, and chronic pain did not affect the changes in pain. In conclusion, even when adjusted for training adherence, performing physical exercise at the workplace is more effective than home-based exercise in reducing musculo-skeletal pain in healthcare workers. Noteworthy, obese individuals may especially benefit from physical exercise interventions targeting musculo-skeletal pain.

Not only age but also tactile perception influences the preference for cosmetic creams applied to the forearm.

OBJECTIVE: We aimed to examine whether and how age as well as tactile sensitivity and perception had an impact on how women liked richer and lighter creams. Furthermore, the question arose if age and tactile perception had an influence on the ability to distinguish between the creams and how the ability to distinguish between creams influenced the liking of these creams. METHODS: A total of 299 female participants were invited to rate how much they liked four different cosmetic creams applied to their forearms. The creams were based on the same base formula but differed with respect to the texture. In order to arouse the impression of more lightness (quasi-light) or more richness (quasi-rich), polyethylene particles of different sizes were added to the base formula. First of all, the participants were tested for their tactile sensitivity and perception. Tactile sensitivity was tested by Von Frey filaments, tactile spatial perception by the tactile Landolt ring test and the ability to discriminate surface structures by a sandpaper test. Furthermore, the participants rated the creams with respect to the acceptance, the subjective skin feeling after application and performed paired-comparison tests. Analyses of variance and regression analyses were applied to the data. RESULTS: In general, participants liked quasi-rich creams less than quasi-light creams. However, older women compared to younger women and women with lower tactile performance in comparison with women with higher tactile performance revealed a weaker influence of cream type-specific acceptance ratings. Further results revealed that young participants perceived the quasi-light creams (with particles of ~50 µm diameter) as soft and quasi-rich creams (with particles of ~100 µm and ~165 µm diameter), as coarse. In contrast, this subjective skin feeling after application in participants at age 50 and older did not differ much. CONCLUSION: Age and tactile perceptual abilities have additive effects on the acceptance of creams with different textures when applied to the forearm.

Quadrupole shift of nuclear magnetic resonance of donors in silicon at low magnetic field.

Shifts from the expected nuclear magnetic resonance frequencies of antimony and bismuth donors in silicon of greater than a megahertz are observed in electrically detected magnetic resonance spectra. Defects created by ion implantation of the donors are discussed as the source of effective electric field gradients generating these shifts via quadrupole interaction with the nuclear spins. The experimental results are modeled quantitatively by molecular orbital theory for a coupled pair consisting of a donor and a spin-dependent recombination readout center.

Squeezing of Quantum Noise of Motion in a Micromechanical Resonator.

A pair of conjugate observables, such as the quadrature amplitudes of harmonic motion, have fundamental fluctuations that are bound by the Heisenberg uncertainty relation. However, in a squeezed quantum state, fluctuations of a quantity can be reduced below the standard quantum limit, at the cost of increased fluctuations of the conjugate variable. Here we prepare a nearly macroscopic moving body, realized as a micromechanical resonator, in a squeezed quantum state. We obtain squeezing of one quadrature amplitude 1.1±0.4 dB below the standard quantum limit, thus achieving a long-standing goal of obtaining motional squeezing in a macroscopic object.

Perfusion territories subtended by penetrating coronary arteries increase in size and decrease in number toward the subendocardium.

Blood flow distribution within the myocardium and the location and extent of areas at risk in case of coronary artery disease are dependent on the distribution and morphology of intramural vascular crowns. Knowledge of the intramural vasculature is essential in novel multiscale and multiphysics modeling of the heart. For this study, eight canine hearts were analyzed with an imaging cryomicrotome, developed to acquire high-resolution spatial data on three-dimensional vascular structures. The obtained vasculature was skeletonized, and for each penetrating artery starting from the epicardium, the dependent vascular crown was defined. Three-dimensional Voronoi tessellation was applied with the end points of the terminal segments as center points. The centroid of end points in each branch allowed classification of the corresponding perfusion territories in subendocardial, midmyocardial, and subepicardial. Subendocardial regions have relatively few territories of about 0.5 ml in volume having their own penetrating artery at the epicardium, whereas the subepicardium is perfused by a multitude of small perfusion territories, in the order of 0.01 ml. Vascular volume density of small arteries up till 400 µm was 3.2% at the subendocardium territories but only 0.8% in the subepicardium territories. Their higher volume density corresponds to compensation for flow impeding forces by cardiac contraction. These density differences result in different scaling law properties of vascular volume and tissue mass per territory type. This novel three-dimensional quantitative analysis may form the basis for patient-specific computational models on coronary perfusion and aid the interpretation of image-based clinical methods for assessing the transmural perfusion distribution.

In vitro optical detection of simulated blood pulse in a human tooth pulp model.

OBJECTIVE: Noninvasive optical methods such as photoplethysmography, established for blood pulse detection in organs, have been proposed for vitality testing of human dental pulp. However, no information is available on the mechanism of action in a closed pulp chamber and on the impairing influence of other than pulpal blood flow sources. Therefore, the aim of the present in vitro study was to develop a device for the optical detection of pulpal blood pulse and to investigate the influence of different parameters (including gingival blood flow [GBF] simulation) on the derived signals. MATERIALS AND METHODS: Air, Millipore water, human erythrocyte suspensions (HES), non-particulate hemoglobin suspension (NPHS), and lysed hemoglobin suspension (LHES) were pulsed through a flexible (silicone) or a rigid (glass) tube placed within an extracted human molar in a tooth-gingiva model. HES was additionally pulsed through a rigid tube around the tooth, simulating GBF alone or combined with the flow through the tooth by two separate peristaltic pumps. Light from high-power light-emitting diodes (625 nm (red) and 940 nm (infrared [IR]); Golden Dragon, Osram, Germany) was introduced to the coronal/buccal part of the tooth, and the signal amplitude [∆U, in volts] of transmitted light was detected by a sensor at the opposite side of the tooth. Signal processing was carried out by means of a newly developed blood pulse detector. Finally, experiments were repeated with the application of rubber dam (blue, purple, pink, and black), aluminum foil, and black antistatic plastic foil. Nonparametric statistical analysis was applied (n = 5; α = 0.05). RESULTS: Signals were obtained for HES and LHES, but not with air, Millipore water, or NPHS. Using a flexible tube, signals for HES were higher for IR compared to red light, whereas for the rigid tube, the signals were significantly higher for red light than for IR. In general, significantly less signal amplitude was recorded for HES with the rigid glass tube than with the flexible tube, but it was still enough to be detected. ∆U from gingiva compared to tooth was significantly lower for red light and higher for IR. Shielding the gingiva was effective for 940 nm light and negligible for 625 nm light. CONCLUSIONS: Pulpal blood pulse can be optically detected in a rigid environment such as a pulp chamber, but GBF may interfere with the signal and the shielding effect of the rubber dam depends on the light wavelength used. CLINICAL RELEVANCE: The optically based recording of blood pulse may be a suitable method for pulp vitality testing, if improvements in the differentiation between different sources of blood pulse are possible.