Random flap survival with hyperbaric oxygen: daily versus twice-daily treatments.

PURPOSE: Hyperbaric oxygen (HBO2) therapy is used to improve the survival of compromised flaps. Compromised flaps are complications encountered postsurgically, or in traumatic degloving or avulsion injuries. Failed flaps lead to persistence of the defect, requirement of another donor site, and psychosocial sequelae. Although evidence of the benefit of HBO2 therapy is significant, there is no consensus on the optimal treatment regimen. The purpose of this study is to examine whether twice-daily treatments (BID HBO2) provide additional benefit compared to daily treatments (QD HBO2) in a rat compromised random flap model. METHODS: A rat random flap model was used with subjects divided into three groups: 1) control group; 2) QD HBO2; and 3) BID HBO2, where HBO2 was performed with 100% oxygen at 2.5 atmospheres absolute/ATA (253 kPa) for 90 minutes. After 10 days, areas of flap necrosis were measured and biopsies were taken for histologic analysis. Statistical analysis was performed using ANOVA and paired t-tests. A P-value ⟨0.05 was considered significant. RESULT: Both treatment groups had significantly increased mean flap survival compared to controls (P⟨0.05). There was no significant difference in flap survival between the QD and BID groups. Capillary proliferation in the QD group was increased compared with controls. CONCLUSION: Both QD and BID HBO2 protocols can significantly decrease random flap necrosis. However, the results of this study suggest there is no additional benefit gained with BID treatments. Clinical studies are warranted to confirm these findings and assist in formalization of protocols for the use of HBO2in treating compromised random flaps.

Yerba mate (Ilex paraguariensis) improves microcirculation of volunteers with high blood viscosity: a randomized, double-blind, placebo-controlled trial.

BACKGROUND: Elevated blood viscosity is a risk factor for atherosclerosis, thrombosis and other cardiovascular events. Our previous studies have suggested that consumption of Yerba mate tea (Ilex paraguariensis) has strong antioxidant and lipid-lowering properties in animals. The in vivo effects of Yerba mate on blood viscosity in humans, however, have not been studied. OBJECTIVE: This study aims to investigate the effect of Yerba mate tea on the reduction of blood viscosity and the improvement of microcirculatory parameters commonly regarded as risk factors for serious cardio and cerebrovascular disorders. METHODS: 142 subjects with high blood viscosity were recruited in this randomized, double-blind, placebo-controlled study. Yerba mate tea or placebo (5 g/day) was administered to different groups for 6 weeks. After treatment, results of hemorheological indexes, nailfold microcirculation, 6-keto-PGF1α and TXB2 and lipid profiles of subjects in the Yerba mate tea group were compared with those in the placebo-receiving group. RESULTS: Parameters of blood viscosity and microcirculation were improved in the subjects from the Yerba mate tea group but not in placebo-receiving patients. After treatment, whole blood viscosity, plasma viscosity and the Equation K value of erythrocyte sedimentation rate (ESRK) decreased significantly in the Yerba mate group. Meanwhile, shape, flow state and nailfold microcirculation appeared positively changed. Specifically, blood flow speeds accelerated gradually and nailfold weighted integral values decreased significantly. Moreover, the vasodilator 6-keto PGF1α increased while the thromboxane TXB2 decreased in serum samples of subjects in the Yerba mate-receiving group. Overall, Yerba mate tea-receiving subjects saw nearly all measured values improve to levels comparable to those characteristic of patients with normal microcirculation. CONCLUSIONS: These results indicate the therapeutic capacity of Yerba mate tea in the treatment of high blood viscosity. Here, Yerba mate tea played a role in the regulation of various indexes of hemorheology, nailfold microcirculation, and the platelet aggregating factors 6-keto-PGF1a and TXB2. The regulation of these might be correlated with reduced blood viscosity and accelerating blood flow. Thus, Yerba mate tea may reduce some key risk-factors of cardiovascular disease. Daily consumption of Yerba mate tea may be a better-tolerated option for individuals with high blood viscosity and microcirculatory disturbance and as such, a novel preventative strategy for patients at-risk for vascular disease.

Supplementation of complex milk lipid concentrate (CMLc) improved the memory of aged rats.

OBJECTIVES: The socio-economic impact from age-related mental decline is escalating. Supplementation of functional foods for sustaining mental health is desirable. We examined the effect of long-term supplementation of complex milk lipid concentrate (CMLc), mixed dairy phospholipids, on memory and associated vascular and neuronal changes in aged rats. METHODS: Fisher/Norway Brown rats were used. Two groups of aged rats (24 months) were fed with either gelatin-formulated CMLc or blank gelatin as the control, for 4 months. To determine age-related changes, a young group (5 months) was also fed with blank gelatin. Morris water maze tests were carried out after the supplementation and brain tissues were collected for biological analysis. RESULTS: The aged control rats learnt to locate the platform slower than the young control rats during acquisition trials (*P < 0.05), and made fewer entries to and more initial heading errors from the platform zone during testing trials (*P < 0.05). The CMLc supplementation improved memory by showing the reduced initial heading errors in a delayed probe trial ((#)P < 0.05). We also found that the aged rats with CMLc supplementation improved vascular density, dopamine output, and neuroplasticity ((#)P < 0.05) in the brain regions involved in memory compared with that of the aged control rats. DISCUSSION: The data suggested that the supplementation of CMLc during the early stage of brain aging may prevent memory decline possibly through improving vascular and neuronal function.

Effects of dietary creatine supplementation on systemic microvascular density and reactivity in healthy young adults.

BACKGROUND: Dietary creatine supplementation (CrS) is a practice commonly adopted by physically active individuals. However, the effects of CrS on systemic microvascular reactivity and density have never been reported. Additionally, CrS is able to influence blood levels of homocysteine, resulting in presumed effects on vascular endothelial function. Thus, we investigated the effects of CrS on the systemic microcirculation and on homocysteine levels in healthy young individuals. METHODS: This open-label study was performed on a group of 40 healthy male, moderately physically active subjects aged 27.7 ± 13.4 years who received one week of CrS at a dose of 20 g/day of commercially available micronized creatine monohydrate. Laser speckle contrast imaging was used in the evaluation of cutaneous microvascular reactivity, and intra-vital video microscopy was used to evaluate skin capillary density and reactivity, before and after CrS. RESULTS: CrS did not alter plasma levels of homocysteine, although CrS increased creatinine (p = 0.0001) and decreased uric acid (p = 0.0004) plasma levels. Significant changes in total cholesterol (p = 0.0486) and LDL-cholesterol (p = 0.0027) were also observed along with a reduction in plasma levels of T3 (p = 0.0074) and an increase in T4 levels (p = 0.0003). Skin functional capillary density (p = 0.0496) and capillary recruitment during post-occlusive reactive hyperemia (p = 0.0043) increased after CrS. Increases in cutaneous microvascular vasodilation induced by post-occlusive reactive hyperemia (p = 0.0078) were also observed. CONCLUSIONS: Oral supplementation with creatine in healthy, moderately physically active young adults improves systemic endothelial-dependent microvascular reactivity and increases skin capillary density and recruitment. These effects are not concurrent with changes in plasma homocysteine levels.

Global and local hard X-ray tomography of a centimeter-size tumor vessel tree.

The visualization of the vascular network in tumors down to the smallest vessels requires high spatial resolution and reasonable contrast. Stained corrosion casts of the microvasculature network guarantee superior X-ray absorption contrast and highest reproduction fidelity. Tomography of a centimeter-size tumor, however, is unfeasible at the spatial resolution needed to reveal the smallest vessels. Therefore, local tomography has been performed to visualize the smallest capillaries within the region of interest. These three-dimensional data show the detailed morphology, but the reconstructed absorption coefficients obtained in local tomography differ substantially from the absorption coefficients retrieved from the less detailed global tomography data. This paper deals with the adaptation of local tomography data using the global data and considers two-parameter histogram matching of the radiographs, sinogram extension, and multi-parameter cupping correction. It is demonstrated that two-parameter histogram matching of the radiographs already provides reasonable agreement. The change of the lens in front of the detector's camera, however, significantly affects the obtained local X-ray absorption coefficients in the tomograms predominantly owing to the dissimilar point-spread functions of the two configurations used, and much less to the fact that one of the data sets was acquired in a local geometry.

Supranutritional selenium increases mammary gland vascularity in postpartum ewe lambs.

Objectives were to determine the effects of maternal dietary supranutritional Se and nutritional plane during gestation on capillary surface density, capillary area density, and angiogenic factor expression in the developing mammary gland of primiparous ewes. Selenium treatments were initiated at breeding [adequate Se (ASe; 9.5 µg/kg of body weight) vs. high Se (HSe; 81.8 µg/kg of body weight)] and nutritional planes at d 50 of gestation [Low, 60%; moderate (Mod), 100%; and High, 140% of requirements). Mammary glands were collected within 24h postpartum. Vascular development was assessed in the glandular portion of the mammary gland. Vascularity was determined for mammary tissue with the following measurements taken: the cross-sectional capillary area density (total capillary area as a proportion of tissue area) and capillary surface density (CSD; total capillary circumference per unit of tissue area). High-Se ewes had greater capillary surface and area densities compared with ASe ewes. A tendency existed for an Se × plane of nutrition interaction for CSD with maternal diet not affecting CSD in HSe ewes, but Low ewes had a decreased CSD compared with Mod ewes, with High being intermediate in ASe ewes. Moreover, HSe-Low and HSe-High ewes had increased CSD compared with ASe-Low and ASe-High, respectively. Although Se status did not influence angiogenic factor mRNA expression, mammary glands from Low ewes tended to have increased VEGF and FLT1 mRNA expression compared with High ewes, with Mod being intermediate. Maternal plane of nutrition did not affect mammary gland glutathione peroxidase activity, but it was increased in HSe compared with ASe ewes. Increased mammary capillary nutrient exchange area may contribute to previously observed changes in colostrum quality.

Normal human epithelial cells regulate the size and morphology of tissue-engineered capillaries.

The survival of thick tissues/organs produced by tissue engineering requires rapid revascularization after grafting. Although capillary-like structures have been reconstituted in some engineered tissues, little is known about the interaction between normal epithelial cells and endothelial cells involved in the in vitro angiogenic process. In the present study, we used the self-assembly approach of tissue engineering to examine this relationship. An endothelialized tissue-engineered dermal substitute was produced by adding endothelial cells to the tissue-engineered dermal substitute produced by the self-assembly approach. The latter consists in culturing fibroblasts in the medium supplemented with serum and ascorbic acid. A network of tissue-engineered capillaries (TECs) formed within the human extracellular matrix produced by dermal fibroblasts. To determine whether epithelial cells modify TECs, the size and form of TECs were studied in the endothelialized tissue-engineered dermal substitute cultured in the presence or absence of epithelial cells. In the presence of normal keratinocytes from skin, cornea or uterine cervix, endothelial cells formed small TECs (cross-sectional area estimated at less than 50 microm(2)) reminiscent of capillaries found in the skin's microcirculation. In contrast, TECs grown in the absence of epithelial cells presented variable sizes (larger than 50 microm(2)), but the addition of keratinocyte-conditioned media or exogenous vascular endothelial growth factor induced their normalization toward a smaller size. Vascular endothelial growth factor neutralization inhibited the effect of keratinocyte-conditioned media. These results provide new direct evidence that normal human epithelial cells play a role in the regulation of the underlying TEC network, and advance our knowledge in tissue engineering for the production of TEC networks in vitro.

Physicochemical, morphological and therapeutic evaluation of agarose hydrogel particles as a reservoir for basic fibroblast growth factor.

Micron-sized agarose hydrogel particles were prepared using an emulsification/gelation method as a controlled release reservoir for basic fibroblast growth factor (bFGF). Mean particle size of agarose hydrogel particles decreased with an increase in stirring speed and also with an increasing temperature of the oil phase, as measured before cooling. Morphologies of agarose particles before and after dispersing into water were investigated by scanning electron microscopy (SEM) and cryogenic SEM, respectively. Freeze-dried agarose particles were spherical with rough surface. Porous polymer matrix structure was observed in the hydrogel particles by cryo-SEM. More than 99% of bFGF was encapsulated and the release from the agarose hydrogel particles was less than 3% during the incubation in phosphate buffered saline. bFGF molecules were not only adsorbed on the particle surface but also permeated and retained within the matrix. The therapeutic efficacy of bFGF retained in agarose hydrogel particles was significantly higher than that dissolved in saline. Agarose hydrogel particle seems to be a potential candidate for a bFGF reservoir.

The circumventricular organs: an atlas of comparative anatomy and vascularization.

The circumventricular organs are small sized structures lining the cavity of the third ventricle (neurohypophysis, vascular organ of the lamina terminalis, subfornical organ, pineal gland and subcommissural organ) and of the fourth ventricle (area postrema). Their particular location in relation to the ventricular cavities is to be noted: the subfornical organ, the subcommissural organ and the area postrema are situated at the confluence between ventricles while the neurohypophysis, the vascular organ of the lamina terminalis and the pineal gland line ventricular recesses. The main object of this work is to study the specific characteristics of the vascular architecture of these organs: their capillaries have a wall devoid of blood-brain barrier, as opposed to central capillaries. This particular arrangement allows direct exchange between the blood and the nervous tissue of these organs. This work is based on a unique set of histological preparations from 12 species of mammals and 5 species of birds, and is taking the form of an atlas.

Morphology of ferret subcutaneous adipose tissue after 6-month daily supplementation with oral beta-carotene.

Adipose tissue is an important retinoid depot and retinoids are known to influence white and brown adipocyte metabolism. Identifying nutrients that can affect the biological activity of the adipose organ would be of great medical interest in the light of the current obesity epidemic and related disorders in developed countries. The vast majority of mammal studies of chronic administration of oral beta-carotene have used murine models, while few have employed mammals exhibiting uptake and processing of intestinal beta-carotene similar to those of humans. While rodents transform practically all ingested beta-carotene into retinol, in ferrets, as in humans, part of the beta-carotene is absorbed and released into the circulation intact. We studied the effects of 6-month daily administration of two doses of oral beta-carotene (0.8 or 3.2 mg/kg/day) on ferret body weight, size of body fat depots, and, using morphological and morphometric methods, on subcutaneous (inguinal) white adipose tissue (WAT). Because of the oral mode of administration, liver, stomach, and small and large intestine were also studied. Control animals received the vehicle. Data show that at the end of treatment the higher dose induced significantly higher body weight compared with controls and significantly higher inguinal fat depot compared with animals treated with the lower dose. In addition, chronic treatment with beta-carotene induced a dose-dependent hypertrophy of white adipocytes and increased neoangiogenesis in subcutaneous WAT in all treated ferrets. Vasculogenesis was independent of adipocyte hypertrophy. We also found focally evident liver steatosis in the ferrets treated with the higher dose of beta-carotene. The other gastrointestinal tract organs studied were not significantly different from those of control animals.

Leakage-resistant blood vessels in mice transgenically overexpressing angiopoietin-1.

Angiopoietin-1 (Ang1) and vascular endothelial growth factor (VEGF) are endothelial cell-specific growth factors. Direct comparison of transgenic mice overexpressing these factors in the skin revealed that the VEGF-induced blood vessels were leaky, whereas those induced by Ang1 were nonleaky. Moreover, vessels in Ang1-overexpressing mice were resistant to leaks caused by inflammatory agents. Coexpression of Ang1 and VEGF had an additive effect on angiogenesis but resulted in leakage-resistant vessels typical of Ang1. Ang1 therefore may be useful for reducing microvascular leakage in diseases in which the leakage results from chronic inflammation or elevated VEGF and, in combination with VEGF, for promoting growth of nonleaky vessels.

Effect of a water-soluble vitamin E analog, trolox C, on retinal vascular development in an animal model of retinopathy of prematurity.

The debate over the efficacy of vitamin E as a therapy for retinopathy of prematurity (ROP) continues 45 years after it was first proposed. The discrepancies between one clinical study and another may be due to the difficulty of delivering a lipid-soluble molecule like vitamin E to the immature retina. Trolox C is a water-soluble analog of vitamin E with potent antioxidant activity. We have studied the effectiveness of intraperitoneal injection of Trolox C in an animal model of ROP. Albino rats were placed in 80% oxygen at birth where they remained for 14 d before sacrifice and assessment of retinal vasculature. Rats were administered 625 microg/kg Trolox C, or vehicle, by intraperitoneal injection on alternate days for the duration of the exposure. Other rats were simultaneously raised in room air, injected, and assessed as controls. Percent avascular retinal area, vascular leakage, and retinal capillary density were measured by computer-assisted image analysis. Trolox C-injected rats had significantly smaller avascular areas (14.6 +/- 4.8% vs. 25.4 +/- 6.3%), less leak area (0.04 +/- 0.07 mm2 vs. 0.16 +/- 0.14 mm2), and greater capillary density (24.3 +/- 2.6 pixel % vs. 18.9 +/- 3.1 pixel %) than vehicle-injected counterparts. These findings indicate that Trolox C facilitated the process of retinal vasculogenesis under hyperoxemic conditions. They also suggest that oxygen free radical-mediated damage plays a role in the pathologic effect of high oxygen rearing of newborn rats. Additional studies are warranted to determine precise site(s) and mechanism(s) of Trolox C activity in this and similar disease models in which peroxidation is believed to play a causal role.

[Vascular characteristics of the lamina terminalis of the human hypothalamus]. / Vaskularne karakteristike lamine terminalis hipotalamusa coveka.

The aim of the study is to discover the sources of vascularization, vascular area, the size and density of the capillary network of the vascular organ of the laminae terminalis of the hypothalamus. The brain blood vessels under examination were filled with a mixture of India ink and gelatin. The serial paraffin sections of 30 and 200 um were cleared after Spalteholz. In the vascularization of this neuroendocrine structure of the hypothalamus, two arterial stems take part with their branches: a cerebri anterior and a. communicans anterior. In order to quantify the density of the capillary network, the authors used standard stereologic parameters - volumene density, surface density and mean radius of blood vessels. While the precise functions of the vascular organ have yet to be fully elucidated, the similarity in organization of this region to the median eminence has led several authors to suggest a neurosecretory role for the vascular organ of the lamina terminalis.

Transport of molecules across tumor vasculature.

The vascular-extravascular exchange of fluid and solute molecules in a tissue is determined by three transport parameters (vascular permeability, P, hydraulic conductivity, Lp, and reflection coefficient, sigma); the surface area for exchange, A; and the transluminal concentration and pressure gradients. The transport parameters and the exchange area for a given molecule are governed by the structure of the vessel wall. In general, tumor vessels have wide interendothelial junctions; large number of fenestrae and transendothelial channels formed by vesicles; and discontinuous or absent basement membrane. While these factors favor movement of molecules across tumor vessels, high interstitial pressure and low microvascular pressure may retard extravasation of molecules and cells, especially in large tumors. These characteristics of the transvascular transport have significant implications in tumor growth, metastasis, detection and treatment.

Effects of iron deficiency on endurance and muscle enzyme activity in man.

The purpose of the present study was to evaluate the effects of iron deficiency on enzyme activities and endurance. Iron deficiency was induced in 9 healthy male subjects by repeated venesections. After a period of 9 wk (range, 8-11 wk) when the subjects had become iron deficient as defined by laboratory parameters, blood was retransfused to reestablish the control hemoglobin concentration. In this state it was possible to evaluate the effect of iron deficiency isolated from anemia. In samples secured by muscle biopsies, glycolytic, oxidative, and iron depending enzymes were analyzed in the control (C) and anemic (A) states and after retransfusion (R). There were no significant changes in the maximal activities of any of the enzymes studied. The capillary/fiber ratio remained unchanged between C (1.92) and R (1.94). Times to exhaustion on treadmill tests were 49 min, 11 s in C, 26 min, 33 s in A, and 52 min, 3 s in R. Vo2max was 4.55 1 X min-1 in C, 3.74 1 X min-1 in A, and 4.45 1 X min-1 in R. An artificially induced iron deficiency defined by conventional laboratory parameters did not affect endurance when transfusion of red blood cells was performed in order to exclude the influence of a low hemoglobin concentration. A 4-wk period of severely depleted or absent tissue iron stores did not affect the maximal activities of various enzymes in human skeletal muscle.

Studies of development of hypothalamic nuclei and hypothalamo-hypophyseal connection in ontogenesis of female rats.

The development of neurocytes of arcuate (ABC) and suprachiasmatic (SC) and the median eminence (ME) together with portal capillaries during embryogenesis and post-natal periods in female Wistar rats were studied at light and electron microscope level. Neurocytes of ARC nucleus producing secretory granules was observed first at 20 day of embryogenesis. After birth the number of such neurocytes producing secretory granules was greatly increased. In SC nucleus the neurocytes begin producing secretory granules in 5...7 day old animals. The results of the karyometric study also reveal that the development of ARC nucleus neurocyte proceeds the SC nucleus. This asynchronous development of tonic (ARC nucleus) and cyclic centre (SC nucleus) probably determines the critical period of sexual programming in female rats. Development of ME including the differentiation of portal capillaries is structurally completed during 3-4 weeks after birth. The significance of these findings in relation to the role of ARC and SC nuclei in sexual cycle regulation in female rats has been pointed out and discussed.

Epithelial mesenchymal interrelations at the skin level. A quantitative study.

Epithelial mesenchymal interrelations at the skin level were quantitatively studied by analysing the modifications of fibrocytes in the framework of total connective cells and capillaries of the dermic mesenchyme and of the number of mitoses in the epidermis. A normal group of guinea pigs was compared with a massaged one (II) and a massaged one using ointment (III). There were found significant differences between the elements of the first and those of the second and third groups, and no significant differences between the 2nd and the 3rd ones. There were established and compared the ratio of dermal fibrocytes to other connective cells, to dermal capillaries and to epidermal mitoses: the ratio remained similar in all groups. These results lead to the conclusion that dermis (expressed by its cells and capillaries) and epidermis (reflected in mitoses) have a correlated response to the mechanical action exerted in physiological limits, and that the epithelial mesenchymal dependence at the skin level is determined by the strong interrelations which are not easily modifiable.

The neurohypophyseal capillary bed. II. Specializations within median eminence.

Vascular casts of the pituitary gland, median eminence and hypothalamus from several mammalian species were examined by scanning electron microscopy. These observations were correlated with light microscopic studies of injected, cleared median eminence-pituitary specimens and with light microscopic examination of serial sections of injected hypothalamic, median eminence, and pituitary specimens employing reflected lighting or epi-illumination. Transmission electron microscopy was employed to study long portal vessels on the ventral surface of the rat median eminence. In each of the species examined, the median eminence (infundibular) capillary bed is subdivided into an external and an internal plexus. The external plexus (the neurohemal contact zone) receives an arterial supply from the superior hypophyseal arteries and is continuous with the capillary bed of the infundibular stem and process. Egress from the external plexus is possible via three vascular routes: (a) by fenestrated portal vessels and capillaries to the adenohypophysis, (b) by capillary connections to the medial basilar hypothalamus and, (c) by internal plexus capillaries to the ependyma of the median eminence. Median eminence vasculature is structurally organized to deliver (1) hypothalamic and neurohypophyseal peptides to the glandular pituitary via portal vessels, (2) hypothalamic and pituitary secretions to the medial basilar hypothalamus via capillaries, and (3) hypothalamic and pituitary secretions to distant brain sites through cerebrospinal fluid via ventricular and subarachnoid routes.

[Morphometric studies of the density and diameter of capillaries in supraoptic and paraventricular nuclei of unmilked and milked cows]. / Morphometrische Untersuchungen über die Kapillardichte und den Kapillardurchmesser im Nucleus supraopticus und Nucleus paraventricularis bei ungemolkenen und gemolkenen Kühen

With mathematical-statistical methods the density and the diameter of the capillaries of the NSO and NPV were investigated by unmilked and milked cows. After the milking the diameter of the capillaries is significantly expanded in both nuclei districts. The density of the capillaries measured through the length of the capillaries pro mm3 tissue, were not significantly enlarged after the milking stimulus. The adaptation on the changed functionstate of the neurosecreoty cells arrive at a maximum 15 min after the milking, to go back afterwards, by 60 min after the milking studied cows, to the values of the beginning. It is discussed, that the intensified blood maintenance of the activated neurosecretory cells of the NSO and NPV is of a higher oxygen consumption.