Features of regional blood flow after endoscopic myomectomy

The state of regional blood flow in 65 patients before and after endoscopic myomectomy was studied using modem methods such as Doppler examination and color Doppler sonography. It was determined that blood flow velocity indeces obtained during the Doppler examination of myoma vessels and uterine arteries allow to estimate the morphological structure of myomas uninvasively and can be used to define the indications for conservative endoscopic surgical procedures in patients with myoma uteri. Doppler monitoring of regional blood flow during postoperative period makes it possible to evaluate the effectiveness of surgical treatment previously performed.

Diabetic mice have retinal and choroidal blood flow deficits and electroretinogram deficits with impaired responses to hypercapnia

Purpose The purpose of this study was to investigate neuronal and vascular functional deficits in the retina and their association in a diabetic mouse model. We measured electroretinography (ERG) responses and choroidal and retinal blood flow (ChBF, RBF) with magnetic resonance imaging (MRI) in healthy and diabetic mice under basal conditions and under hypercapnic challenge. Methods Ins2Akita diabetic (Diab, n = 8) and age-matched, wild-type C57BL/6J mice (Ctrl, n = 8) were studied under room air and moderate hypercapnia (5% CO2). Dark-adapted ERG a-wave, b-wave, and oscillatory potentials (OPs) were measured for a series of flashes. Regional ChBF and RBF under air and hypercapnia were measured using MRI in the same mice. Results Under room air, Diab mice had compromised ERG b-wave and OPs (e.g., b-wave amplitude was 422.2±10.7 μV in Diab vs. 600.1±13.9 μV in Ctrl, p < 0.001). Under hypercapnia, OPs and b-wave amplitudes were significantly reduced in Diab (OPs by 30.3±3.0% in Diab vs. -3.0±3.6% in Ctrl, b-wave by 17.9±1.4% in Diab vs. 1.3±0.5% in Ctrl). Both ChBF and RBF had significant differences in regional blood flow, with Diab mice having substantially lower blood flow in the nasal region (ChBF was 5.4±1.0 ml/g/min in Diab vs. 8.6±1.0 ml/g/min in Ctrl, RBF was 0.91±0.10 ml/g/min in Diab vs. 1.52±0.24 ml/g/min in Ctrl). Under hypercapnia, ChBF increased in both Ctrl and Diab without significant group difference (31±7% in Diab vs. 17±7% in Ctrl, p > 0.05), but an increase in RBF was not detected for either group. Conclusions Inner retinal neuronal function and both retinal and choroidal blood flow were impaired in Diab mice. Hypercapnia further compromised inner retinal neuronal function in diabetes, while the blood flow response was not affected, suggesting that the diabetic retina has difficulty adapting to metabolic challenges due to factors other than impaired blood flow regulation.

Osteoporotic mid-thoracic vertebral body fractures: what are the differences compared to fractures of the lumbar spine?—a systematic review

Purpose The aim of this systematically review is to detect differences between fractures located at the mid-thoracic spine compared to fractures of the thoracolumbar junction (TLJ) and the lumbar spine in osteoporotic vertebral body fractures. Methods This review is based on articles retrieved by a systematic search in the PubMed and Web of Science database for publications regarding osteoporotic fractures of the thoracolumbar spine with respect to the fracture location. Differences in prevalence, cause of fracture, fracture healing, and outcomes between the mid-thoracic spine and the TLJ and the lumbar spine were considered. Results Altogether, 238 articles could be retrieved from the literature search. A total of 222 articles were excluded. Thus, 16 remaining original articles were included in this systematic review comprising the topics prevalence, bone mineral density and regional blood flow, biomechanics, subsequent fractures, and outcome, respectively. The overall level of evidence of the vast majority of studies was moderate to low. Conclusion Several differences between osteoporotic fractures of the mid-thoracic spine compared to the TLJ and the lumbar spine could be identified. Thereby, osteoporotic mid-thoracic fractures seem to be particularly more related to frailty without a history of traumatic injury compared to osteoporotic fractures of the TLJ and the lumbar spine. Additionally, the presence of severe mid-thoracic fractures predicts subsequent fractures of the hip. In contrast, subsequent fractures of the spine are less likely.

Spatiotemporal components of sustained functional hyperemia are differentially modulated by locomotion and silenced with vascular chemogenetics

Neural activity underlying sensation, movement or cognition drives regional blood flow enhancement (termed functional hyperemia) to increase the oxygen supply to respiring cells for as long as needed to meet energy demands. However, functional hyperemia is often studied under anesthesia which typically yields response profiles that appear temporally and spatially homogenous. We have insufficient understanding of the underlying kinetics of oxygen delivery in awake animals, especially during specific behaviours that may influence neurally-driven enhancements in cerebral blood flow. Using widefield intrinsic optical signal imaging in awake, head-fixed but active mice, we demonstrated distinct early and late components to changes in intravascular oxygenation in response to sustained (30s) whisker stimulation. We found that the late component (20-30s), but not the early component (1-5s), was strongly influenced by level of whisking/locomotion in the region of highest response and in surrounding regions. Optical flow analyses revealed complex yet stereotyped spatial properties of the early and late components that were related to location within the optical window and the initial state of the cerebral vasculature. In attempt to control these complex response characteristics, we drove a canonical microvasculature constriction pathway using mural cell Gq-chemogenetic mice. A low-dose of systemic C21 strongly limited both the magnitude and spatial extent of the sensory-evoked hemodynamic response, showing that functional hyperemia can be severely limited by direct mural cell activation. These data provide new insights into the cerebral microcirculation in the awake state and may have implications for interpreting functional imaging data.

Hemodynamic phenotyping of transgenic rats with ubiquitous expression of an angiotensin-(1-7)-producing fusion protein

Activation of the angiotensin (Ang) converting enzyme 2/Ang-(1-7)/MAS receptor pathway of the renin-angiotensin system induces protective mechanisms in different diseases. Herein, we describe the cardiovascular phenotype of a new transgenic rat line (TG7371) that expresses an Ang-(1-7)-producing fusion protein. The transgene-specific mRNA and the corresponding protein were shown to be present in all evaluated tissues of TG7371 with the highest expression in aorta and brain. Plasma Ang-(1-7) levels, measured by radioimmunoassay were similar to control SD rats, however high Ang-(1-7) levels were found in the hypothalamus. TG7371 showed lower baseline mean arterial pressure, assessed in conscious or anesthetized rats by telemetry or short-term recordings, associated with increased plasma ANP and higher urinary sodium concentration. Evaluation of regional blood flow and hemodynamic parameters with fluorescent microspheres showed a significant increase in blood flow in different tissues (kidneys, mesentery, muscle, spleen, brown fat, heart and skin), with a resulting decreased total peripheral resistance. TG7371 rats also presented increased cardiac and global sympathetic tone, increased plasma AVP levels and decreased free water clearance. Altogether, our data show that expression of an Ang-(1-7)-producing fusion protein induced a hypotensive phenotype due to widespread vasodilation and consequent fall in peripheral resistance. This phenotype was associated with an increase in ANP together with an increase in AVP and sympathetic drive, which did not fully compensate the lower BP. Here we present the hemodynamic impact of long-term increase in tissue expression of an Ang-(1-7)-fusion protein and provide a new tool to investigate this peptide in different pathophysiological conditions.

Impact of region-of-interest size and location on quantitative contrast-enhanced ultrasound of canine splenic perfusion

Background During contrast enhanced ultrasound (CEUS), the features of the regions of interest (ROI) can affect the value of the perfusion-related parameters obtained from a time intensity curve (TIC). In veterinary medicine, conflicting have been reported on the influence of ROI size and location on renal CEUS. There are some disagreeing evidences regarding the optimal method for selecting ROI in quantitative analysis of renal perfusion using CEUS. The aim of this study was to evaluate the effect of the size and location of ROIs in the spleen of conscious dogs on perfusion variables determined using sulphur hexafluoride contrast-enhanced ultrasounds. Results A prospective observational study on 15 client-owned mixed-breed adult dogs was performed using a system equipped with contrast-tuned imaging technology. Qualitative and quantitative assessments of the spleen enhancement pattern were carried out. Three square ROIs (0.05 cm2) were manually drawn in a row and spaced 1 mm apart, placing adjacent ROIs at three different depths. Three medium rectangular ROIs (0.3 cm2) include the 3 smallest ROIs in each row, indicated by the letters A, B and C, and a single large square ROI (1 cm2) was drawn containing all previous ROIs. Software analysis of time-intensity curves generated within each ROI allowed us to calculate the perfusion-related parameters: peak enhancement, time to peak, regional blood flow, mean transit time and regional blood volume. The coefficient of variation for all blood-related parameters was always lower in the larger ROI than in the other smaller ROIs. ROI A and B, positioned proximally and medially, levels respectively, showed similar coefficients of variation to the largest ROI. The analysis of variance model exhibited a significant effect of location and size of the ROIs in the quantitative analysis of canine spleen perfusion, with a reduction of perfusion-related parameters in the distal ROI. Conclusions The recommendation for a quantitative CEUS examination of a dog’s spleen is to analyze splenic perfusion by drawing a sufficiently large ROI proximal to the ultrasound beam on the splenic parenchyma. This may be of clinical relevance in the diagnosis of splenic diseases.

Influence of autologous bone marrow fraction and simvastatin on microcirculation of leg muscles in experimental critical ischemia of the lower limbs

Introduction. The effectiveness of cell therapy at the stage of critical limb ischemia is insufficient for regression of clinical manifestations of the ischemic process. Aim – to develop an experimental model of critical limb ischemia and to study the effect of the combined use of bone marrow autocells and simvastatin on the perfusion of ischemic tissues and the dynamics of the clinical picture of the ischemic process. Materials and methods. The experimental study was carried out on 180 male Wistar rats, divided into 6 groups of 30 animals each. In the first group (intact), the level of microcirculation in the muscles of the hind limb was determined. In the second group (sham-operated), the neurovascular bundle of the thigh was isolated and the wound was sutured with a continuous suture. In the third group, chronic critical ischemia of the leg muscles was modeled by removing the femoral, popliteal, anterior and posterior tibial arteries and veins, and damage to the peripheral nerve. In the fourth group, critical ischemia of the leg muscles was treated with simvastatin, in the fifth group – with the mononuclear fraction of autologous bone marrow, in the sixth one – with simvastatin and the mononuclear fraction of autologous bone marrow. The level of microcirculation in the leg muscles was determined using laser Doppler flowmetry LDF 100C and invasive needle sensor TSD144 on days 10, 21 and 28. Results. In the second group, a statistically insignificant decrease in the level of microcirculation was noted. In the third group, the level of regional blood flow in the ischemic muscle of the leg of rats on the 10th day was 2.5 times, on the 21st day – 1.7 times and on the 28th day 1.4 times less than in the group of intact animals. At the same time, in the fourth group after the administration of simvastatin to the animals, the regional blood flow increased 1.4; 1.5 and 1.5 times; in the fifth group, with the introduction of the mononuclear fraction of the bone marrow to animals at all periods, 1.6 times; in the sixth group after the combined administration of bone marrow cells and simvastatin – 2.0; 1.8 and 1.7 times. By the end of the experiment, in the animals of the fourth and fifth groups, it was possible to stop the progression of clinical manifestations, and in animals of the sixth group, their regression was achieved. Conclusion. The combined use of bone marrow cells and statins allows bringing the level of perfusion of ischemic tissues to normal and achieving regression of the clinical picture of the ischemic process by the end of the experiment.

Postdecompressive spinal cord blood flow increments in a cervical chronic myelopathy model in rats

OBJECTIVE In cervical spondylotic myelopathy (CSM), compromise of blood flow to the compressed spinal cord has been postulated to contribute to the development of myelopathy. Although decompressive surgery has been considered to improve spinal cord blood flow, evidence to support this notion is scarce. To determine whether blood flow improves after decompressive surgery for CSM, regional blood flow was measured in a model of chronic cervical compression in rats by using a fluorescent microsphere technique. METHODS Thin polyurethane sheets, measuring precisely 3 × 5 × 0.7 mm, were implanted under the C5–6 laminae in 24 rats to induce continuous compression on the cervical spinal cord. These sheets expand gradually by absorbing tissue fluid. This animal model has been demonstrated to reproduce the clinical features and histological changes of CSM, including progressive motor weakness with delayed onset and insidious tissue damage prior to symptom onset. Twenty-four rats that underwent sham operation were allocated to a control group. To confirm the development of cervical myelopathy, motor functions were measured weekly over the study period. Nine weeks after implantation of the sublaminar expanding sheets, histological studies and C5–6 decompressive surgery were conducted. Regional blood flow in the brainstem and cervical spinal cord was measured sequentially until 120 minutes after decompression. RESULTS In the CSM group, bilateral forepaw grip strength deteriorated progressively from 5 weeks after implantation. In the compressed C5–6 segment of the spinal cord, significant flattening of the cord, a decreased number of motor neurons, and vacuolations of gray matter were demonstrated. In the control group, blood flow in the brainstem and cervical spinal cord was unchanged by the decompressive surgery. In the CSM group, however, diminished blood flow and continuous blood flow increments for 120 minutes after decompression were demonstrated in the compressed C5–6 spinal cord segment. CONCLUSIONS Chronic mechanical compression induced regional spinal cord blood flow insufficiency concomitant with progressive neuronal loss and motor dysfunction in a chronic compression model in rats. Decompressive surgery increased spinal cord blood flow. These findings suggest that blood flow recovery may contribute to postoperative neurological improvement.