[Assessment of microhaemodynamics and oxygenation in tissues after the vestibuloplasty with the use of a free dermal autograft in patients after the reconstructive jaw surgery with the use of the revascularized autografts]. / Otsenka sostoyaniya mikrogemodinamiki i oksigenatsii v tkanyakh posle vestibuloplastiki s ispol'zovaniem svobodnogo dermal'nogo autotransplantata u patsientov posle rekonstruktivnoi operatsii na chelyustyakh s primeneniem revaskulyarizirovannykh autotransplantatov.

Purpose of the study: to study the features of microhaemodynamics and oxygenation in soft tissues in the area of the plastically reconstructed jaw after the vestibuloplasty. MATERIALS AND METHODS: The study included 40 patients aged 20 to 65 (21 males and 19 females). The patients were divided into two groups: I group (14 patients) - patients after reconstructive surgery with the use a fibula autograft without the inclusion of a musculocutaneous «islet¼; II group (26 patients) - patients after reconstructive surgery with the use a fibula autograft with the inclusion of a musculocutaneous «islet¼. To correct the prosthetic bed soft tissues, all patients underwent vestibuloplasty with the use of a free dermal autograft. To study microcirculation in tissues, the laser Doppler flowmetry (LDF) method was used. Microcirculation status was assessed by microcirculation index characterizing the level of tissue blood flow; parameter «σ,¼ which determines the oscillability of the flow of red blood cells and by coefficient of variation, characterizing vasomotor activity of microvessels. According to the Wavelet analysis of LDF-grams the blood flow bypass was determined. An oxygenation study was carried out in the tissues of the plastically restored jaw by optical tissue oximetry, the results of which determined the oxygenation index and the specific oxygen consumption index. RESULTS: According to LDF data after vestibuloplasty, it was found that in I group, the microcirculation in soft tissues of the plastically reconstructed jaw restored in 21 days, and in II group in 2 months, which persisted at 6 months. In I group, the level of oxygenation and specific oxygen consumption normalized in 21 days, and in II group in 2 months, which persisted at 6 months. CONCLUSION: Based on the results of this functional study, it was found that before vestibuloplasty microcirculation and oxygenation indices in II group patients were lower than those in I group patients. After vestibuloplasty with the use of a free dermal autograft, microcirculation indices in II group patients restored in 2 months, while in I group patients those indices restored in 21 days.

Morphologic Mapping of the Sublingual Microcirculation in Healthy Volunteers.

PURPOSE: Monitoring the sublingual and oral microcirculation (SM-OM) using hand-held vital microscopes (HVMs) has provided valuable insight into the (patho)physiology of diseases. However, the microvascular anatomy in a healthy population has not been adequately described yet. METHODS: Incident dark field-based HVM imaging was used to visualize the SM-OM. First, the SM was divided into four different fields; Field-a (between incisors-lingua), Field-b (between the canine-first premolar-lingua), Field-c (between the first-second premolar-lingua), Field-d (between the second molar-wisdom teeth-lingua). Second, we investigated the buccal area, lower and upper lip. Total/functional vessel density (TVD/FCD), focus depth (FD), small vessel mean diameters (SVMDs), and capillary tortuosity score (CTS) were compared between the areas. RESULTS: Fifteen volunteers with a mean age of 29 ± 6 years were enrolled. No statistical difference was found between the sublingual fields in terms of TVD (p = 0.30), FCD (p = 0.38), and FD (p = 0.09). SVMD was similar in Field-a, Field-b, and Field-c (p = 0.20-0.30), and larger in Field-d (p < 0.01, p = 0.015). The CTS of the buccal area was higher than in the lips. CONCLUSION: The sublingual area has a homogenous distribution in TVD, FCD, FD, and SVMD. This study can be a description of the normal microvascular anatomy for future researches regarding microcirculatory assessment.

Improved microvascular reactivity after aged garlic extract intake is not mediated by hydrogen sulfide in older adults at risk for cardiovascular disease: a randomized clinical trial.

PURPOSE: This study aimed to investigate the effects of AGE on microvascular reactivity, systolic blood pressure (SBP), and diastolic blood pressure (DBP) in older individuals at high risk for cardiovascular disease (CVD). Urinary thiosulfate was also investigated as an indirect marker of endogenous hydrogen sulfide (H2S) synthesis. The study was conducted in a randomized, double-blind, crossover, and placebo-controlled way. METHODS: Twenty-eight participants (14 male), 67 ± 6 years old with CVD risk factors, ingested 2.4 g of AGE or placebo (PLA). Near-infrared spectroscopy evaluated tissue oxygen saturation (StO2) during a vascular occlusion test (30 s baseline, 5 min occlusion, and 2 min reperfusion). The upslope of StO2 signal after cuff release was calculated to measure microvascular reactivity. Urinary thiosulfate levels were measured using a high-performance liquid chromatography system. RESULTS: The upslope of StO2 was significantly faster after AGE (1.01 ± 0.37% s-1) intake compared to PLA (0.83 ± 0.35% s-1; P < 0.001; d = 0.50). Relative changes in Δ% SBP from pre- to post-AGE intake (- 5.17 ± 5.77%) was significantly different compared to Δ% PLA (0.32 ± 5.99%; P = 0.001; d = 0.93). No significant changes in urinary thiosulfate concentrations were observed between interventions. Moreover, no significant gender effect in any parameter assessed was found. CONCLUSION: This study demonstrated that a single dose of AGE improved microvascular reactivity in older adults at risk of CVD despite such an effect was not linked with urinary thiosulfate levels. This trial was registered at clinicaltrials.gov as NCT04008693 (May 19, 2020).

[Modern achievements of the functional diagnostics in dentistry]. / Sovremennye dostizheniya funktsional'noi diagnostiki v stomatologii.

The article presents the development of functional research methods in the maxillofacial region, methods of their application and the results of scientific research on the study of the neuromuscular balance of the masticatory muscles with defects and deformations in the maxillofacial region. Methods of blood circulation research (laser doppler flowmetry, ultrasound dopplerography, computer capillaroscopy) have been developed and implemented in the tissues of the maxillofacial region: periodontal, tooth pulp, in the mucous membrane of the alveolar ridge, which allowed us to study the mechanisms of disease pathogenesis and monitor the effectiveness of treatment in the maxillofacial region.

Determination of baseline alveolar mucosa perfusion parameters using laser Doppler flowmetry and tissue spectrophotometry in healthy adults.

Objectives: To determine the baseline perfusion parameters of the alveolar mucosa using laser Doppler flowmetry and tissue spectrophotometry (LDF-TS) in healthy adults.Material and methods: Forty-two healthy adult subjects of either sex were tested. The perfusion of the alveolar mucosa was evaluated using a laser Doppler flowmetry and tissue spectrophotometry using O2C 'oxygen to see' device. The measurements encompassed the maxillary and mandibular mucosa at 20 different points.Results: The O2C device is a reliable method for noninvasive measurement of different perfusion parameters of the oral mucosa. The hemoglobin saturation values (So2 in %), as well as relative amount of hemoglobin in arbitrary units (AU) of the maxillary mucosa demonstrated lower values of that in the mandible. The flow value (AU) exhibited a significant difference in the posterior molar region only, while the velocity value (AU) showed a significant difference across all points except for the anterior region.Conclusion: the present study provides a set of brand-new perfusion parameters of the microcirculation of the alveolar mucosa using LDF-TS. The study suggests a variation of the perfusion parameters between the maxilla and the mandible. Differences in the anatomy of the blood supply, the thickness of the mucosa and the cortical bone, may be attributed to this variation. Further studies using different probes and a combination of ultrasonic measurements and SDF imaging will aid in giving a better overview of the perfusion in the oral mucosa.

Effect of Polyethylene-glycolated Carboxyhemoglobin on Renal Microcirculation in a Rat Model of Hemorrhagic Shock.

BACKGROUND: Primary resuscitation fluid to treat hemorrhagic shock remains controversial. Use of hydroxyethyl starches raised concerns of acute kidney injury. Polyethylene-glycolated carboxyhemoglobin, which has carbon monoxide-releasing molecules and oxygen-carrying properties, was hypothesized to sustain cortical renal microcirculatory PO2 after hemorrhagic shock and reduce kidney injury. METHODS: Anesthetized and ventilated rats (n = 42) were subjected to pressure-controlled hemorrhagic shock for 1 h. Renal cortical PO2 was measured in exposed kidneys using a phosphorescence quenching method. Rats were randomly assigned to six groups: polyethylene-glycolated carboxyhemoglobin 320 mg · kg, 6% hydroxyethyl starch (130/0.4) in Ringer's acetate, blood retransfusion, diluted blood retransfusion (~4 g · dl), nonresuscitated animals, and time control. Nitric oxide and heme oxygenase 1 levels were determined in plasma. Kidney immunohistochemistry (histologic scores of neutrophil gelatinase-associated lipocalin and tumor necrosis factor-α) and tubular histologic damages analyses were performed. RESULTS: Blood and diluted blood restored renal PO2 to 51 ± 5 mmHg (mean difference, -18; 95% CI, -26 to -11; P < 0.0001) and 47 ± 5 mmHg (mean difference, -23; 95% CI, -31 to -15; P < 0.0001), respectively, compared with 29 ± 8 mmHg for hydroxyethyl starch. No differences between polyethylene-glycolated carboxyhemoglobin and hydroxyethyl starch were observed (33 ± 7 mmHg vs. 29 ± 8 mmHg; mean difference, -5; 95% CI, -12 to 3; P = 0.387), but significantly less volume was administered (4.5 [3.3-6.2] vs. 8.5[7.7-11.4] ml; mean rank difference, 11.98; P = 0.387). Blood and diluted blood increased the plasma bioavailability of nitric oxide compared with hydroxyethyl starch (mean rank difference, -20.97; P = 0.004; and -17.13; P = 0.029, respectively). No changes in heme oxygenase 1 levels were observed. Polyethylene-glycolated carboxyhemoglobin limited tubular histologic damages compared with hydroxyethyl starch (mean rank difference, 60.12; P = 0.0012) with reduced neutrophil gelatinase-associated lipocalin (mean rank difference, 84.43; P < 0.0001) and tumor necrosis factor-α (mean rank difference, 49.67; P = 0.026) histologic scores. CONCLUSIONS: Polyethylene-glycolated carboxyhemoglobin resuscitation did not improve renal PO2 but limited tubular histologic damages and neutrophil gelatinase-associated lipocalin upregulation after hemorrhage compared with hydroxyethyl starch, whereas a lower volume was required to sustain macrocirculation.

MicroRNA-21 Contributes to Reduced Microvascular Function in Binge Drinking Young Adults.

BACKGROUND: Binge drinking is associated with increased risk for cardiovascular (CV) disease. MicroRNA-21 (miR21) is up-regulated in the setting of excessive alcohol consumption and CV disease. Therefore, the goal of this study was to examine the vasodilatory responses to flow and acetylcholine (ACh) in the absence and presence of an anti-miR21 inhibitor in the microcirculation of young adult repeated binge drinkers (BDs). METHODS: Gluteal subcutaneous adipose tissue biopsies were obtained from young adults (18 to 30 years, n = 35 vessels from BDs and n = 28 vessels from abstainers). Resistance arteries (RAs) were isolated, incubated with anti-miR21 or a negative control (NC) to miR21 (12 hours; 50 nM), and lumen diameters measured with video microscopy. miR21 of adipose tissues was determined by quantitative polymerase chain reaction. RESULTS: Flow-induced dilation and ACh-induced dilation (AChID) were reduced in BDs as compared to abstainers. The miR21 inhibitor but not the NC abrogated these effects in BDs, but did not affect vasodilation in abstainers. Nitric oxide synthase inhibition with L-NAME reduced vasodilation in abstainers but not in BDs. In BDs, vasodilation was reduced by L-NAME in the presence of anti-miR21 but not the NC. Scavenging the reactive oxygen species, hydrogen peroxide with polyethylene glycol catalase reduced dilation in BDs but did not affect the restored dilation by the miR21 inhibitor. Maximum dilation to papaverine (endothelium independent) was similar between groups and unaffected by pharmacological inhibition. Finally, vascular endogenous miR21 was increased in BDs compared to abstainers. CONCLUSIONS: Endogenous miR21 is increased in RAs of young BDs, leading to reduced flow and AChID in the microcirculation.

Cross-sectional association between oral health and retinal microcirculation.

AIM: To investigate the relation between oral health status and microcirculation, we analysed the association between periodontitis and number of teeth with retinal vessel diameters in a population-based study. METHODS: We analysed data from the Study of Health in Pomerania-TREND (SHIP-TREND). All subjects (3,183 for number of teeth, 3,013 for mean probing depth and 2,894 for mean attachment level) underwent nonmydriatic funduscopy and dental examination. We measured central retinal arteriolar (CRAE), venular (CRVE) vessel diameters and calculated arterio-venous ratio (AVR) from static vessel analysis (SVA). Periodontal status was assessed using the case definition of the Center for Disease Control and Prevention/American Academy of Periodontology (CDC/AAP). Data were analysed by linear (CRAE, CRVE, AVR) and logistic regression (AVR < 0.8) adjusted for age, sex, smoking status, alcohol consumption, body mass index, systolic blood pressure, hsCRP and type-2-diabetes mellitus. RESULTS: Only in men, significant associations were found between periodontal and retinal conditions. Severe periodontitis [ß = -0.0120 (-0.0218; -0.0007 95%-CI)] and mean probing depth [ß = -0.0054 (-0.0105; -0.0002 95%-CI)] were inversely associated with AVR; severe periodontitis [ß = 3.80 (0.61; 6.98 95%-CI)], mean probing depth [ß = 1.86 (0.23; 3.49 95%-CI)] and mean attachment level [ß = 1.31 (0.34; 2.27 95%-CI)] with CRVE and mean attachment level with CRAE [ß = 0.91 (0.14; 1.69 95%-CI)]. CONCLUSIONS: Our results point towards an association between periodontal conditions and AVR in men. Periodontitis may impact microvascular endothelium function. Improving oral health to reduce periodontitis might lead to reduced risk for other age-related diseases.

A Quantitative Analysis of Microcirculation in Skin Defects Covered with Topical Wound Dressings or a Newly Developed Collagen Matrix.

OBJECTIVE: Innovative skin substitutes and temporary wound dressings are frequently used in the treatment of superficial and partial-thickness wounds. The aim of this study was to compare 2 commonly used temporary skin dressings with a newly developed collagen matrix to determine changes in microcirculation as measured by blood flow, hemoglobin oxygenation, and relative hemoglobin values during healing of partial-thickness skin defects. METHODS: This animal study involved 28 adult male Lewis rats. On the back of each rat, 2 standardized partial-thickness skin defects were generated through a skin dermatome (n = 56). Then, wounds were treated with polylactide-based copolymer skin substitute (Suprathel, PolyMedics, Denkendorf, Germany; n = 14), biosynthetic skin dressing (Biobrane, Smith & Nephew, Hamburg, Germany; n = 14), or Collagen Cell Carrier (CCC; Naturin Viscofan, Weinheim, Germany; n = 14). The remaining control wounds were left untreated (n = 14). MAIN OUTCOME MEASURES: Perfusion dynamics were assessed every 10 days for 80 days with the O2C device (LEA Medizintechnik, Gießen, Germany) to determine blood flow, hemoglobin oxygenation, and relative amount of hemoglobin. MAIN RESULTS: Blood flow was increased in all wounds for at least 30 days after wound generation. The relative amounts of hemoglobin were increased in superficial layers (2 mm) for 10 to 20 days. Hemoglobin oxygenation in the superficial layers decreased in the polylactide-based copolymer skin substitute and biosynthetic skin dressing-treated groups and initially increased in the untreated wounds and CCC groups on day 10; these values also decreased. CONCLUSIONS: The presented results demonstrate the complex changes in microcirculation in the course of healing partial-thickness wounds with different wound dressings and contribute to a better understanding of these wounds. However, based on the results of the study, a clear recommendation for a specific substitute is not yet possible.

Apoptosis and reduced microvascular density of the lamina propria during tooth eruption in rats.

During tooth eruption, structural and functional changes must occur in the lamina propria to establish the eruptive pathway. In this study, we evaluate the structural changes that occur during lamina propria degradation and focus these efforts on apoptosis and microvascular density. Fragments of maxilla containing the first molars from 9-, 11-, 13- and 16-day-old rats were fixed, decalcified and embedded in paraffin. The immunohistochemical detection of vascular endothelial growth factor (VEGF), caspase-3 and MAC387 (macrophage marker), and the TUNEL method were applied to the histological molar sections. The numerical density of TUNEL-positive cells and VEGF-positive blood vessel profiles were also obtained. Data were statistically evaluated using a one-way anova with the post-hoc Kruskal-Wallis or Tukey test and a significance level of P ≤ 0.05. Fragments of maxilla were embedded in Araldite for analysis under transmission electron microscopy (TEM). TUNEL-positive structures, fibroblasts with strongly basophilic nuclei and macrophages were observed in the lamina propria at all ages. Using TEM, we identified processes of fibroblasts or macrophages surrounding partially apoptotic cells. We found a high number of apoptotic cells in 11-, 13- and 16-day-old rats. We observed VEGF-positive blood vessel profiles at all ages, but a significant decrease in the numerical density was found in 13- and 16-day-old rats compared with 9-day-old rats. Therefore, the establishment of the eruptive pathway during the mucosal penetration stage depends on cell death by apoptosis, the phagocytic activity of fibroblasts and macrophages, and a decrease in the microvasculature due to vascular cell death. These data point to the importance of vascular rearrangement and vascular neoformation during tooth eruption and the development of oral mucosa.

MP4CO, a pegylated hemoglobin saturated with carbon monoxide, is a modulator of HO-1, inflammation, and vaso-occlusion in transgenic sickle mice.

Transgenic sickle mice expressing ß(S) hemoglobin have activated vascular endothelium in multiple organs that exhibits enhanced expression of NF-ĸB and adhesion molecules and promotes microvascular stasis in sickle, but not normal, mice in response to hypoxia/reoxygenation (H/R), or heme. Induction of heme oxygenase-1 (HO-1) or administration of its products, carbon monoxide (CO) or biliverdin, inhibits microvascular stasis in sickle mice. Infusion of human hemoglobin conjugated with polyethylene glycol and saturated with CO (MP4CO) markedly induced hepatic HO-1 activity and inhibited NF-ĸB activation and H/R-induced microvascular stasis in sickle mice. These effects were mediated by CO; saline or MP4 saturated with O2 (MP4OX) had little to no effect on H/R-induced stasis, though unmodified oxyhemoglobin exacerbated stasis. The HO-1 inhibitor, tin protoporphyrin, blocked MP4CO protection, consistent with HO-1 involvement in the protection afforded by MP4CO. MP4CO also induced nuclear factor-erythroid 2 p45-related factor 2 (Nrf2), an important transcriptional regulator of HO-1 and other antioxidant genes. In a heterozygous (hemoglobin-AS) sickle mouse model, intravenous hemin induced cardiovascular collapse and mortality within 120 minutes, which was significantly reduced by MP4CO, but not MP4OX. These data demonstrate that MP4CO induces cytoprotective Nrf2 and HO-1 and decreases NF-ĸB activation, microvascular stasis, and mortality in transgenic sickle mouse models.

Therapeutic effect of methotrexate encapsulated in cationic liposomes (EndoMTX) in comparison to free methotrexate in an antigen-induced arthritis study in vivo.

OBJECTIVES: Cationic lipid complexes bind to angiogenic endothelial cells of solid tumours and microvessels of chronic inflammatory tissue. Methotrexate (MTX) is one of the drugs used in the therapy of rheumatoid arthritis (RA); it is applied systemically but can have serious side-effects. The aim of this study was to investigate the impact of MTX encapsulated in cationic liposomes (EndoMTX) in comparison to treatment with free MTX. METHOD: We used an antigen-induced arthritis (AiA) model and investigated the leucocyte- and platelet-endothelial cell interaction in arthritic female C57/Bl6 mice and in healthy controls. The arthritic animals were divided into four different groups receiving either trehalose, free MTX, EndoMTX placebo, or EndoMTX. These parameters and functional capillary density (FCD) were measured and assessed by intravital microscopy (IVM). We controlled clinical parameters such as the knee joint diameter (KJD) throughout the observation period. RESULTS: Animals treated with EndoMTX showed a significant and superior reduction in leucocyte- and platelet-endothelial cell interaction, FCD, and KJD. Free MTX or empty liposomes also showed a reduction in these parameters but not to a significant level. FCD decreased in the EndoMTX group in comparison to using free drugs or empty carrier-like liposomes. CONCLUSIONS: This study demonstrates the advantage of using MTX encapsulated in cationic liposomes in contrast to free and generic MTX, with a higher efficacy in anti-inflammatory and anti-angiogenic abilities. Targeting with cationic liposomes may be a promising treatment option and should be elucidated in further experiments regarding dose reduction and side-effects due to MTX usage.

Periodontitis and retinal microcirculation in the Atherosclerosis Risk in Communities study.

AIM: The aim of this cross-sectional study is to explore if periodontitis is associated with alterations of the retinal microcirculation, a predictive marker of cardiovascular events. MATERIAL AND METHODS: Of 457 subjects aged 52 years and more from the ARIC cohort were included. Retinal vascular diameters were measured and summarized as central retinal arteriolar/venular equivalents (CRAE/CRVE). Periodontitis was determined by using the CDC/AAP definition. Multivariable linear regression models were used to estimate the relationships between CRAE, CRVE and periodontitis. RESULTS: No association was found between CRAE and periodontal status. However, CRVE and severe periodontitis were positively and significantly associated. Mean CRVE (±SD) was 187.0 ± 17.2 µm in the health-gingivitis group, and, respectively, 188.5 ± 16.3 µm (p = 0.39) and 191.6 ± 16.8 µm (p = 0.04) in moderate and severe periodontitis groups, after adjustment for a propensity score based on confounders. Results were consistent when analyses were restricted to participants with diabetes mellitus (n = 66), but not diabetes-free subjects. CONCLUSIONS: Severe periodontitis is associated with larger retinal venular diameter in patients with type 2 diabetes. Further studies are needed to explore the impact of diabetes mellitus on the association between periodontitis and retinal microcirculation.

Improvement of microcirculation and wound healing in vertical ridge augmentation after pre-treatment with self-inflating soft tissue expanders - a randomized study in dogs.

OBJECTIVES: We investigated the effect of soft tissue expansion (STE) on vertical ridge augmentation with regard to the incidence of wound dehiscences and the impairment of microcirculation in dogs, and the applicability of laser Doppler flowmetry (LDF) to explore the relation between microcirculation and wound healing. MATERIAL AND METHODS: Bone defects were created on both mandibular sides in ten beagle dogs by extraction of premolars and removal of bone. Six weeks later, self-filling tissue expanders were implanted in randomly assigned test sites. After 5 weeks of expansion, vertical augmentation was carried out in test and control sites using calvarial onlay grafts side by side with granular biphasic calcium phosphate covered with a resorbable polyethylene glycol membrane. Microcirculation was evaluated with laser Doppler flowmetry (LDF). The incidence of wound dehiscences was evaluated after 2 weeks. The validity of LDF to predict dehiscences was evaluated by construction of receiver operating characteristic (ROC) curves. RESULTS: After augmentation, test sites showed significantly better perfusion than control sites without preceding STE (P = 0.012). Three days after surgery, perfusion was still significantly decreased in control sites (P = 0.005), while microcirculation in test sites had returned to pre-surgical levels. After 2 weeks, healing in test sites was good, whereas eight dehiscences were found in control sites (P = 0.002). ROC curves showed that microcirculation levels immediately after augmentation surgery significantly predicted subsequent wound dehiscences (AUC = 0.799, CI 0.642-0.955, P = 0.006). CONCLUSIONS: Laser Doppler flowmetry is suitable for evaluation of soft tissue microcirculation after ridge augmentation. STE reduced the impairment of microcirculation caused by vertical ridge augmentation and decreased the incidence of wound dehiscences in the investigated animal model.

Soft tissue biological response to zirconia and metal implant abutments compared with natural tooth: microcirculation monitoring as a novel bioindicator.

INTRODUCTION: Zirconia is often used for implant abutments for esthetics. The aim of this clinical study was to compare the effects of zirconia and metal abutments on periimplant soft tissue. MATERIALS AND METHODS: Ten maxillary anterior implant patients, 5 with metal abutments and 5 with zirconia abutments, were enrolled in this trial. The soft tissue around the implant abutments was evaluated by 2-dimensional laser speckle imaging and thermography. The blood flow in soft tissue around natural teeth was also measured to correct for differences among the subjects. RESULTS: Significantly greater blood flow was detected in the zirconia abutment group (95.64 ± 5.17%) relative to the metal abutment group (82.25 ± 8.92%) in free gingiva (P = 0.0317). Reduced blood flow (by almost 18%) was detected in the tissue surrounding metal abutments compared with the tissue surrounding natural teeth. The surface temperature showed no significant difference for all measurements. CONCLUSIONS: These results suggest that blood flow in tissue surrounding zirconia abutments is similar to that in soft tissue around natural teeth. Moreover, zirconia abutments could be advantageous for the maintenance of immune function by improving blood circulation.

[DETERMINATION OF THE STATE OF MICROCIRCULATION BY MEANS OF COMPUTER CAPILLAROSCOPY IN CHILDREN SEDATED WITH RETENTION OF CONSCIOUSNESS IN OUTPATIENT PEDIATRIC DENTAL TREATMENT].

UNLABELLED: Dental treatment of infants and pre-school children is challenging because of high rate of dental fear General anesthesia is the only option for behavioral control in this age group. In case of minor medical procedure physical restrain is also used often enough aggravating the fear An alternate method for comfortable treatment is monitored conscious sedation (MCS). Standard techniques of monitoring do not always provide accurate determination of stress level in children since the external stress manifestations may appear non-significant and unobtrusive. Computer capillaroscopy (CC) allows real time evaluation of early functional disorders at the microlevel and of anesthesia efficiency in vivo. OBJECTIVE AND METHODS: The research involved 298 children. 256 of them were treated under MCS and 42 constituted reference group treated without MCS. The groups were also divided into subgroups according to age: 0-3 and 3-6 year olds. Therapeutic and surgical treatment features were analyzed separately. MCS was conducted by means of intramuscular injection of midazolam in dosages of 0.1, 0.15, and 0.2 mg per kg. BIS, arterial blood pressure, heart rate, respiratory rate, and SpO2 were monitored at 4 stages while the following microcirculation parameters were recorded by CC: density of capillary net, the size of arterial, venous and transitional microcirculation links (ML), linear and volume bloodflow velocity, perfusion balance. The obtained data were statistically processed and analyzed with the use of Statistica Stat Soft 8.0 software. CONCLUSIONS: Children undergoing dental treatment without MCS are affected by stress. The degree of stress in surgical patients was noted to be significantly higher The absence of physiological parameters changes in children treated without MSC is not a proof of the absence of stress. The dose of 0.15 mg per kg is optimal for the comfortable level of MSC. The increase of midazolam-dose over 0.15 mg per kg is not associated with further reduction of stress. The obtained data is true for both age categories.

A novel method for in vivo visualization of the microcirculation of the mandibular periosteum in rats.

OBJECTIVE: The periosteum plays an important role in bone physiology, but observation of its microcirculation is greatly limited by methodological constraints at certain anatomical locations. This study was conducted to develop a microsurgical procedure which provides access to the mandibular periosteum in rats. METHODS: Comparisons of the microcirculatory characteristics with those of the tibial periosteum were performed to confirm the functional integrity of the microvasculature. The mandibular periosteum was reached between the facial muscles and the anterior surface of the superficial masseter muscle at the external surface of the mandibular corpus; the tibial periosteum was prepared by dissecting the covering muscles at the anteromedial surface. Intravital fluorescence microscopy was used to assess the leukocyte-endothelial interactions and the RBCV in the tibial and mandibular periosteum. Both structures were also visualized through OPS and fluorescence CLSM. RESULTS: The microcirculatory variables in the mandibular periosteum proved similar to those in the tibia, indicating that no microcirculatory failure resulted from the exposure technique. CONCLUSION: This novel surgical approach provides simple access to the mandibular periosteum of the rat, offering an excellent opportunity for investigations of microcirculatory manifestations of dentoalveolar and maxillofacial diseases.

Preliminary study of video imaging of blood vessels in tissues lining the gingival sulcus in periodontally healthy individuals.

BACKGROUND AND OBJECTIVE: The aim of this study was to obtain in vivo images of the microcirculation in tissues lining the gingival crevice in periodontally healthy volunteers and to assess the repeatability of the parameters measured. MATERIAL AND METHODS: Video microscopy images of the microcirculation of tissues lining the gingival crevice were obtained from 20 periodontally healthy volunteers. Images were obtained with a single 1 mm diameter 1 pitch gradient index lens with a high numerical aperture and with a plain glass lens and illumination with a green 525 nm light-emitting diode and recorded using a video microscope. RESULTS: The morphological features of the vessels (including vessel diameter, vessel density, loops, branches, dilated vessels) were similar to those described previously in other mammals. The Kappa values for the assessment of morphology of the vessels using the gradient index lens range from 0.83 for branching to 0.91 for dilated and using the glass lens 0.47 for branching and 0.38 for dilated. CONCLUSIONS: This novel system allowed for a consistent and repeatable assessment of the gingival microvasculature. However, there was some evidence of possible pressure artefacts in those cases where the measurements of separation between vessels exceeded 150 µm.

[Study of reconstruction of digital three-dimensional model of normal human placental vascular network based on MRI data in vitro].

OBJECTIVE: To investigate the reconstruction of digital three-dimensional (3D) model of normal human placental vascular network based on MRI data in vitro. METHODS: Six full term placentas were collected, casted with modified self-curing denture base resin and scanned by T1 e-THRIVE high resolution magnetic resonance imaging. MRI images were imported into Mimics 14.0 software for 3D reconstruction, and the 3D model was compared with placental vascular casting model. RESULTS: (1) The placental vascular network could be obtained on MR 2D images. The 3D model were reconstructed successfully, which showed clear, realistic images. The 3D model could be zoomed and revolved from any direction to observe the branches of arteries and veins. (2) The umbilical vein and 2 umbilical arteries could be seen in the 3D model. In the root of the umbilical cord, the umbilical vein divided into 5-7 branches. While the 2 umbilical arteries anatomoses to form blood sinus and then devided into sub-branches. All the peripheral vessels ended in chorionic plate with abundant sub-branches. (3) When compared with the casting of placental arterial-venous vascular network, the morphology, structure, angle and trend of vessels in 3D model was consistent with the casting network. CONCLUSIONS: Reconstruction of digital 3D model of normal human placental vascular network based on MRI in vitro is a new and promising method for the study of placental vasculature. It has better vascular exposure, free rotation, radiation-free. It provides a promising base for the study of placental vasculature in vivo in the future.

High-molecular-weight linear polymers improve microvascular perfusion after extracorporeal circulation.

High-molecular-weight linear polymers (HMWLPs) have earned the name "drag-reducing polymers" because of their ability to reduce drag in turbulent flows. Recently, these polymers have become popular in bioengineering applications. This study investigated whether the addition of HMWLP in a venoarterial extracorporeal circulation (ECC) model could improve microvascular perfusion and oxygenation. Golden Syrian hamsters were instrumented with a dorsal skinfold window chamber and subjected to ECC using a circuit comprised of a peristaltic pump and a bubble trap. The circuit was primed with lactated Ringer solution (LR) containing either 5 ppm of polyethylene glycol (PEG) with a low molecular weight of 500 kDa (PEG500k) or 5 ppm of PEG with a high molecular weight of 3,500 kDa (PEG3500k). After 90 min of ECC at 15% of the animal's cardiac output, the results showed that the addition of PEG3500k to LR improved microvascular blood flow in arterioles and venules acutely (2 h after ECC), whereas functional capillary density showed improvement up to 24 h after ECC. Similarly, PEG3500k improved venular hemoglobin O2 saturation on the following day after ECC. The serum and various excised organs all displayed reduced inflammation with the addition of PEG3500k, and several of these organs also had a reduction in markers of damage with the HMWLPs compared to LR alone. These promising results suggest that the addition of small amounts of PEG3500k can help mitigate the loss of microcirculatory function and reduce the inflammatory response from ECC procedures.NEW & NOTEWORTHY High-molecular-weight linear polymers have gained traction in bioengineering applications. The addition of PEG3500k to lactated Ringer solution (LR) improved microvascular blood flow in arterioles and venules acutely after extracorporeal circulation (ECC) in a hamster model and improved functional capillary density up to 24 h after ECC. PEG3500k improved venular hemoglobin O2 saturation and oxygen delivery acutely after ECC and reduced inflammation in various organs compared to LR alone.