bluuebunny/crossref_metadata_2025 huggingface dataset:
Expression of Zonula Occludens and Adherens Junctional Proteins in Human Venous and Arterial Endothelian Cells: Role of Occludin in Endothelial Solute Barriers
Authors: KEVIL CHRISTOPHER G. , OKAYAMA NAOTSUKA , TROCHA STEVEN D. , KALOGERIS THEODORE J. , COE LAURA L. , SPECIAN ROBERT D. , DAVIS CHRISTOPHER P. , ALEXANDER J. STEVEN
Published: January 2010

Objective: The purpose of this study was to correlate the expression of occludin and VE‐cadherin with the solute barrier properties of arterial and venous endothelial monolayers.

Methods: Immunofluorescent confocal and traditional microscopy were used to determine junctional protein localization in endothelium in vivo and in vitro respectively, and western and northern analysis used to determine protein and gene expression levels. Permeability of endothelial monolayers was examined under normal, low calcium, and cytochalasin‐D treatment conditions. Antisense oligonucleotide experiments for occludin were performed to determine the contribution of occluding to solute barrier.

Results: Occludin protein in endothelial monolayers in more concentrated in arterial junctions than in venous junctions both in vivo and in vitro. Arterial endothelial cells express 18‐fold more occluding protein and nine times more occluding mRNA compared to venous endothelial cells. In vivo, both endothelial cells demonstrate VE‐cadherin staining; in vitro, only venous endothelial cells express VE‐cadherin protein and mRNA. Occludin antisense experiments suggest that both arterial and venous barrier properties are due to these different amounts of occluding expression. Venous barrier was remarkably sensitive to low extracellular calcium, while arterial barrier was more sensitive to cytochalasin‐D.

Conclusions: These findings suggest strongly that arterial and venous endothelial barrier reflects the level of expression of different adhesion molecules and that modulation of these proteins, especially occluding, may regulate the level of endothelial solute barrier.
Superoxide Dismutase Restores Impaired Histamine‐Induced Increase in Venular Macromolecular Efflux During Diabetes Mellitus
Authors: MAYHAN WILLIAM G. , SHARPE GLENDA M.
Published: January 2010

The goal of this study was to determine the role of oxygen radicals in impaired histamine‐induced increases in venular macromolecular efflux from the hamster cheek pouch. We used intravital fluorescent microscopy and fluorescein isothio‐cynate dextran (FITC‐dextran; MW = 70 K) to examine macromolecular extravasation from post‐capillary venules in nondiabetic and diabetic (2–4 weeks after injection of streptozoticin) hamsters in response to histamine. Increases in extravasation of macromolecules were quantitated by counting venular leaky sites and by calculating clearance (ml/s × 10−6) of FITC‐dextran‐70 K. In non‐diabetic hamsters, superfusion with histamine (1.0 and 5.0 µM) increased venular leaky sites from 0 ± 0 to 17 ± 6 and 35 ± 6 per 0.11 cm2, respectively. In addition, clearance of FITC‐dextran‐70 K increased during superfusion with histamine. In contrast, superfusion with histamine did not increase the formation of venular leaky sites (0 ± 0) or clearance of FITC‐dextran‐70 K in diabetic hamsters. Next, we examined whether alterations in histamine‐induced increases in macromolecular efflux in diabetic hamsters may be related to the production of oxygen radicals. We examined whether exogenous application of superoxide dismutase (150 U/ml) could restore impaired histamine‐induced increases in macromolecular extravasation in diabetic hamsters. Application of superoxide dismutase did not alter histamine‐induced increases in venular leaky sites or clearance of FITC‐dextran‐70 K in nondiabetic hamsters. However, application of superoxide dismutase restored histamine‐induced increases in leaky site formation and clearance of FITC‐dextran‐70 K in diabetic hamsters towards that observed in nondiabetic hamsters. These findings suggest that oxygen radical formation appears to contribute to impaired macromolecular efflux in response to histamine during short‐term diabetes mellitus.
A β‐Actin Isotype Is Present in Rat Cardiac Endothelial Cells But Not in Cardiac Myocytes
Authors: GLYN MATTHEW C.P. , WARD BARBARA J.
Published: January 2010

Objective: Active constriction in cardiac capillary endothelial cells (CCECs) is controversial. It is thought by many researchers that CCECs are not actively involved in constriction; others believe that these cells do contribute some of the force required for capillary constriction. Because actin is a major component of most contractile mechanisms responsible for changing cell shape, we compared two probes as potential monitors of actin distribution in CCECs in situ.

Methods: We used SDS‐PAGE, Western blotting, electron microscopy, conventional epifluorescence and confocal microscopy to evaluate an antibody against non‐muscle β‐actin and fluorescently labeled phalloidin to detect actin in CCECs.

Results: Fluorescently labeled phalloidin detected actin in cardiac muscle and faintly in CCECs. The antibody probe detected non‐muscle β‐actin in CCECs. However, this actin isotype did not occur in cardiac myocytes. In endothelial cells non‐muscle β‐actin was concentrated at the cell periphery, and arranged as bundles of fibers, not as typical stress fibers.

Conclusions: Phalloidin is not suitable as a probe to monitor actin distribution in CCEC's in situ. The antibody is a potentially useful tool in monitoring the actin cytoskeleton and determining the capacity of CCECs for active vasoconstriction in vivo. Non‐muscle β‐actin in CCECs is arranged in filament bundles which are not typical stress fibers.
Endothelin Mediates a Component of the Enhanced Myogenic Responsiveness Of Arterioles From Hypertensive Rats
Authors: FALCONE JEFF C. , MEININGER GERALD A.
Published: January 2010

Objective: To determine if the enhanced pressure‐induced constriction of arterioles isolated from hypertensive rats is mediated by the endothelium.

Methods: We utilized isolated, cannulated first‐order arterioles (80 to 110 µm, i.d.) from the rat cremaster muscle of spontaneously hypertensive (SHR) and normotensive (WKY) rats. Arteriolar diameter was measured in response to changes in intraluminal pressures as well as various pharmacological agents in the presence and absence of an intact endothelial cell lining.

Results: All arterioles developed intrinsic tone (approximately 74% of passive). Pressure‐diameter relationships over a pressure range of 30 to 170 cm H2O demonstrated that the myogenic response of arterioles derived from both WKY and SHR was not dependent upon an intact endothelium. However, at higher pressures (>170 cm H2O) the ability of the denuded arteriole from the SHR to maintain a constricted diameter was completely abolished. Treatment of arterioles from the SHR having intact endothelium with diclofenac (10−5 M; 30 min) to inhibit the effect of cyclooxygenase had no effect on the high pressure constriction. In contrast, application of BQ‐123 (10−7 M; 30 min), an ET‐A receptor blocker used to inhibit vascular smooth muscle responses to endothelin, completely abolished the arteriolar constriction at higher pressures.

Conclusions: Therefore, in the hypertensive, arteriolar vasomotor responses to changes in intraluminal pressure is due to at least two mechanisms; one that is intrinsic to vascular smooth muscle (i.e., myogenic) and a second that involves an endothelial cell release of endothelin.
The Pancreas as a Source of Cardiovascular Cell Activating Factors
Authors: KISTLER ERIK B. , HUGLI TONY E. , SCHMID‐SCHÖNBEIN GEERT W.
Published: January 2010

Objective: Physiological shock leads to elevated levels of plasma factors that activate circulating leukocytes and endothelial cells, thereby compromising microvascular functions. The nature and source of these plasma‐derived activators are unknown. To examine the possible origin of these factors, we homogenized rat internal organs and measured their activity on cardiovascular cells in vivo and in vitro.

Methods: Fresh tissue samples from small intestine, spleen, heart, liver, kidney, adrenals, and pancreas were homogenized. Their ability to induce leukocyte pseudopod formation and nitroblue tetrazolium (NBT) reduction was tested and their impact in vivo on blood pressure, survival, and microvascular cell injury was examined.

Results: A dramatic increase (p < 0.001) in leukocyte activation compared to controls was observed with pancreas homogenate but not with homogenates from the other organs. Leukocyte activation was induced by homogenates of other tissues only after prior incubation with substimulatory concentrations of pancreatic homogenate. Pancreatic serine proteases, trypsin and chymotrypsin, which did not stimulate leukocytes, also generated activity from other tissues. Leukocyte pseudopod formation could be significantly inhibited by adding the serine protease inhibitor 6‐amidino‐2‐naphthyl p‐guanidinobenzoate dimethanesulfonate (ANGD) during tissue homogenization (p < 0.001). Injection of pancreatic homogenate into rats led to increased plasma hydrogen peroxide levels and an instantaneous drop in mean arterial pressure that was often lethal. These responses were prevented by prior infusion of ANGD (p < 0.001). Intravital microscopy of the rat mesentery confirmed that superfusion of filtered pancreatic homogenate leads to significant increases in cell death (p < 0.05), as detected by propidium iodide, and hydrogen peroxide formation (p < 0.05), as determined by dichlorofluorescein diacetate (DCFH) fluorescence.

Conclusion: These results suggest that pancreatic enzymes attack tissue and generate cellular activators that are associated with organ dysfunction in shock.
Requirement of Arteriovenular Pairing for Increased Capillary Filtration During Acute Inflammation
Authors: BARNIDGE JASON , HARRIS NORMAN R.
Published: January 2010

Objective: The purpose of this study was to determine whether the leukocyte chemoattractant N‐formyl methionyl‐leucyl‐phenylalanine (FMLP) increases capillary fluid filtration rate (Jv/S), and if so, to determine whether the mechanism involves arteriovenular communication.

Methods: Intravital microscopy was used in the rat mesentery to measure capillary Jv/S by a micro‐occlusion technique. FMLP was locally superfused through a micropipette near vessels in three different arrangements: 1) near a venule in close pairing with the arteriole feeding the monitored capillary, 2) near an unpaired arteriole feeding the capillary, or 3) near an unpaired venule draining the capillary. In separate experiments, arteriolar hydrostatic pressure (downstream of arteriovenular pairing sites exposed to FMLP) was measured with a micropressure system.

Results: FMLP increased capillary Jv/S when applied to arteriovenular pairing sites, but not when applied to unpaired arterioles or venules. Micropressure measurements in paired arterioles remained essentially constant during FMLP exposure, suggesting that the increase in Jv/S is primarily due to increased capillary permeability.

Conclusions: With FMLP applied locally to stimulate leukocytes, arteriovenular pairing is required to observe an increase in capillary filtration rate.
Contribution of Extrinsic Factors and Intrinsic Vascular Alterations to Reduced Arteriolar Reactivity with High‐Salt Diet and Hypertension
Authors: FRISBEE JEFFERSON C. , SYLVESTER FRANCIS A. , LOMBARD JULIAN H.
Published: January 2010

Objective: To determine whether the impaired relaxation of skeletal muscle arterioles of rats on high‐salt diet or with reduced renal mass hypertension (RRM‐HT) represents intrinsic alterations to microvessels alone, or whether extravascular influences also contribute to reduced dilator responses.

Methods: Normotensive (NT) Sprague‐Dawley rats were fed low‐salt (LS) or high‐salt (HS) diets, and RRM‐HT rats were fed HS diet for 4–6 weeks. In situ and isolated cremaster muscle first‐order arterioles (1A) were examined using television microscopy, and a video micrometer was used to measure diameter changes in response to acetylcholine (ACH), cholera toxin (CT), and sodium nitroprusside (SNP).

Results: Compared to normotensive low‐salt (NT‐LS) rats, responses of 1A to the agonists were reduced in normotensive high‐salt (NT‐HS) and RRM‐HT rats. Arteriolar reactivity to the agonists in NT‐LS rats and in NT‐HS rats was not different between in situ and in vitro environments. However, in RRM‐HT rats, the reactivity of 1A to each agonist was greater in isolated arterioles than in in situ arterioles.

Conclusions: These results suggest that the impaired response of skeletal muscle arterioles to vasodilator stimuli in normotensive rats on high‐salt diet primarily reflects alterations to microvessels alone, while reduced dilator responses in RRM‐HT rats represent a combination of extravascular influences and intrinsic alterations to arterioles themselves.
Roles of Endothelial Cell Migration and Apoptosis in Vascular Remodeling during Development of the Central Nervous System
Authors: HUGHES SUZANNE , CHAN‐LING TAILOI
Published: January 2010

Objective: To examine the roles of apoptosis, macrophages, and endothelial cell migration in vascular remodeling during development of the central nervous system.

Methods: The terminal deoxynucleotide transferase‐mediated dUTP nick end labeling (TUNEL) technique was combined with Griffonia simplicifolia isolectin B4 histochemistry to detect apoptotic endothelial cells in retinal whole‐mount preparations derived from rats at various stages of postnatal development as well as from rat pups exposed to hyperoxia. Macrophages were detected by immunohistochemistry with the monoclonal antibody ED1, and proliferating endothelial cells were identified by incorporation of bromodeoxyuridine.

Results: Only small numbers of TUNEL‐positive endothelial cells were detected during normal development of the retinal vasculature, with the apoptotic cell density in the inner plexus peaking during the first postnatal week and decreasing markedly during the second week, at a time when vessel retraction was widespread. Neither apoptotic endothelial cells nor macrophages were apparent at sites of initiation of vessel retraction. TUNEL‐positive endothelial cells were observed in vessels destined to remain. Hyperoxia induced excessive vessel withdrawal, resulting in the generation of isolated vascular segments containing apoptotic endothelial cells. A topographical analysis showed low numbers of proliferating endothelial cells at sites of angiogenesis whereas vascular proliferation was increased in the adjacent inner plexus.

Conclusions: Endothelial cell apoptosis and macrophages do not initiate vessel retraction, but rather contribute to the removal of redundant cells throughout the vasculature. We suggest that vessel retraction is mediated by endothelial cell migration and that endothelial cells derived from retracting vascular segments are redeployed in the formation of new vessels. Only when retraction results in compromised circulation and redeployment is not possible, does endothelial cell apoptosis occur.
Interaction of Endothelin‐1 and Nitric Oxide in Endothelial Barrier Failure in the Cat Hindlimb
Authors: PORTER LINDA P. , McNAMEE JAMES E. , WOLF MATTHEW B.
Published: January 2010

Objective: To determine the interactions of endothelin‐1 (ET‐1) and nitric oxide (NO) in the regulation of endothelial barrier function in skeletal muscle.

Methods: The protein sieving coefficient (1 − σf) was measured as an index of microvascular permeability in the isolated, perfused cat hindlimb preparation. The measurement was made to determine 1) the effects of ET‐1 and NO on basal permeability by blocking the ETAreceptor with BQ123 and NO production with the NO‐synthase inhibitorsl‐NAME orl‐NMMA; 2) if elevated NO (SNAP) affects permeability; and 3) the interaction of ET‐1 and NO by ascertaining if NO‐synthase inhibition or elevated NO can block the ET‐1‐induced permeability increases. Additionally, vascular resistance was determined under these conditions to see if increased microvascular pressures or increased shear stress might play a role in the permeability changes.

Results: Blocking either the ETAreceptor or basal NO production did not affect basal permeability. Likewise, raising NO levels did not affect this permeability. Blocking the ETAreceptor blocked the ability of ET‐1 to cause a profound barrier failure. Increased NO also could block this ET‐1‐induced effect. Blocking the ETAreceptor or elevating NO blocked the 2.5‐fold increase in vascular resistance induced by ET‐1.

Conclusions: Since the ETAreceptor does not reside on skeletal muscle endothelium, it is not likely that ET‐1 acts directly on the endothelium to produce its effects. It could act through 1) increases in shear stress secondary to an ET‐1‐induced vasoconstriction; 2) ET‐1‐induced increases in microvascular pressure sufficient to cause an inflammatory reaction; or 3) stimulation of other cell types, such as leukocytes, to release inflammatory mediators that could damage the endothelium.
Transport of Viral‐Size Particulate Matter after Intravenous versus Intralymphatic Entry
Authors: FOKIN ALEXANDER A. , ROBICSEK FRANCIS , MASTERS THOMAS N.
Published: January 2010

Objective: Investigation of the transport of viral‐size particles after intravenous versus intralymphatic injection and the functional validity of lymphatico‐venous communications.

Methods: In the canine model, [99mTc] sulfur colloid particles (100–200 nm) were injected into either the principal vein or into the main lymphatic channel exposed at the paw. Samples of blood and lymph were collected at the groin from the cannulated femoral vein and from a major lymphatic vessel. Parameters including particle arrival time, concentration, flux, and accumulation were determined for a 45‐minute period using gamma counting.

Results: After intralymphatic injection, particles arrived in the venous blood in an average of 4 seconds. The mean arrival time of particles in the lymph after intravenous injection was 25.4 ± 6.44 minutes. Intralymphatic injection increased lymph flow and enhanced particle transport. Concentration values in the venous blood after intralymphatic injection and in lymph after intravenous injection were comparable. Flux values depended primarily on flow conditions. Particle accumulation in the lymph after intravenous injection was delayed, but continued to increase throughout the experiment.

Conclusions: There are functional lymphatico‐venous communications at the very peripheral level under physiological conditions, which allow rapid transport of viral‐size particulate matter between the two pathways and may contribute to the spread of viral infection.
Therapeutic Management of Chronic Venous Insufficiency: Microcirculation as a Target
Authors: BERGAN JOHN J. , SCHMID‐SCHÖNBEIN GEERT W.
Published: January 2010

Chronic venous insufficiency, in its most severe manifestations as well as in its mild form, is linked to venous valve failure, weakness of the venous wall, and leukocyte‐endothelial interactions all of which lead to cutaneous and subcutaneous tissue changes. These in turn are related to venous hypertension‐induced leukocyte activation, which may provide a target for pharmacotherapeutic intervention. Currently, surgical attack is focused on correction of the sources of venous hypertension, but it is felt that this provides a crude method that hopefully will be replaced by more precise pharmacological interventions.
Biological Properties of Flavonoids Pertaining to Inflammation
Authors: MANTHEY JOHN A.
Published: January 2010

Chronic venous insufficiency (CVI) is accompanied by a marked inflammatory response that is thought to contribute to the development and progression of the disorder. While compression therapy has long been considered the standard treatment for CVI, recent studies suggest that treatment with flavonoids may also be beneficial. The purpose of this review is to summarize how plant flavonoids attenuate inflammation and the immune response through their inhibition of important regulatory enzymes. Certain flavonoids are potent inhibitors of the production of prostaglandins, a group of powerful proinflammatory signaling molecules. Studies have shown that this effect is due to flavonoid inhibition of key enzymes involved in prostaglandin biosynthesis (i.e., lipoxygenase, phospholipase, and cyclooxygenase). Flavonoids also inhibit phosphodiesterases involved in cell activation. Much of this effect is upon the biosynthesis of protein cytokines that mediate adhesion of circulating leukocytes to sites of injury. The protein kinases are another class of regulatory enzymes affected by flavonoids. The inhibition of kinases is due to the competitive binding of flavonoids with ATP at catalytic sites on the enzymes. These modes of inhibition provide the mechanisms by which flavonoids inhibit the inflammation response and suggest that this class of molecules may be effective in the treatment of CVI.
Micronized Purified Flavonoid Fraction and the Treatment of Chronic Venous Insufficiency: Microcirculatory Mechanisms
Authors: SMITH PHILIP D. COLERIDGE
Published: January 2010

The standard treatments for venous diseases of the lower limb include compression bandaging and stockings as well as surgical removal of varicose veins. There is a number of conditions in which these conventional treatments are ineffective, particularly in the management of leg ulceration. Drug treatments for healing venous leg ulcers have yet to be developed to the stage of good clinical efficacy, but may assist in the management of patients. Flavonoid drugs have been widely used in the management of the symptoms of venous disease for many years and have recently been studied in some detail to assess their effects on the microcirculation. Work in animal models of ischemia/reperfusion (I/R) show that micronized purified flavonoid fraction (MPFF) modulates leukocyte adhesion and prevents endothelial damage. Similar biochemical effects have been observed in patients with venous disease and may explain the efficacy of this drug in the management of edema and other symptoms of venous disease. There is some evidence that MPFF promotes venous leg ulcer healing.
Angiogenesis Induced by Electrical Stimulation Is Mediated by Angiotensin II and VEGF
Authors: AMARAL SANDRA L. , LINDERMAN J. RUSSELL , MORSE MELISSA M. , GREENE ANDREW S.
Published: January 2010

Objective: Physiological angiogenesis in skeletal muscle is an adaptive response to physical training and electrical stimulation. This study investigated the role of angiotensin II (Ang II) in regulating both angiogenesis and vascular endothelial growth factor (VEGF) protein expression induced by electrical stimulation.

Methods: The right tibialis anterior (TA) and extensor digitorum longus (EDL) muscles of Sprague‐Dawley rats were stimulated for 8 hours per day for 7 days. The contralateral muscles served as controls. Two days before the surgery and throughout the stimulation protocol, the rats received either lisinopril or losartan in their drinking water. Rats without any drug treatment were used as control. Immunohistochemistry and Western blot analysis were performed to identify the source and quantify the VEGF protein expression in these muscles. The relationship between angiogenesis and VEGF expression was explored using a VEGF‐neutralizing antibody.

Results: Chronic electrical stimulation of the skeletal muscles led to significant increases in vessel density (14% and 30% for EDL and TA, respectively) within 7 days. In addition, stimulation increased VEGF protein levels in the stimulated muscles. Both lisinopril and losartan blocked elevation in VEGF expression and inhibited the angiogenesis induced by stimulation. VEGF neutralization also inhibited angiogenesis, confirming the relationship between Ang II, VEGF, and vessel growth.

Conclusion: The current study suggests a pathway involving angiotensin II receptors (AT1) and VEGF in electrically stimulated angiogenesis.
Pores in the Sieve and Channels in the Wall: Control of Paracellular Permeability by Junctional Proteins in Endothelial Cells
Authors: BAZZONI GIANFRANCO , DEJANA ELISABETTA
Published: January 2010

Exchange of solutes and ions between the luminal and abluminal compartments of the circulation is critically dependent on the barrier properties of the vascular endothelium. Transport of solutes and fluids occurs along the transcellular and paracellular pathways that are mediated by intracellular vesicles and intercellular junctions, respectively. Although the ability of endothelial cells to dynamically regulate permeability has long been recognized, the precise mechanism and the signaling pathways involved have not been fully elucidated. Finally, current definition of the complex molecular composition of intercellular junctions is expected to explain the difference in permeability between diverse segments of the circulation and possibly to highlight the existence of specific junctional channels. The properties of junctional adhesion molecule‐1 (JAM‐1) and vascular endothelial cadherin (VE‐cadherin), two transmembrane components of interendothelial junctions, are described in detail.
Association between Shear Stress, Angiogenesis, and VEGF in Skeletal Muscles In Vivo
Authors: MILKIEWICZ M. , BROWN M. D. , EGGINTON S. , HUDLICKA O.
Published: January 2010

Objective: To investigate the hypothesis that capillary proliferation in skeletal muscles, induced by a long‐term increase in blood flow which elevates capillary shear stress, is associated with capillary expression of vascular endothelial growth factor (VEGF).

Methods: Adult rats received prazosin in drinking water (∼2 mg per day) or had extensor digitorum longus (EDL) muscles stimulated by implanted electrodes for up to 14 days. At intervals, serial frozen sections of EDL were stained for alkaline phosphatase to identify capillaries, proliferating cell nuclear antigen (PCNA), and VEGF‐A protein. Shear stress was estimated from capillary red blood cell velocities and diameters, measured by direct observation of epiilluminated EDL.

Results: Chronic stimulation and prazosin treatment both increased capillary: fiber ratio by ∼40% after 14 days. In stimulated muscles, the percentage of capillaries positively stained for VEGF increased within 3 to 4 days, while the density of PCNA‐positive capillaries had increased 20‐fold after 2 days. With prazosin, VEGF‐positive capillaries increased after 2 and 4 days, accompanied by a threefold increase in PCNA. By 14 days, PCNA labeling and VEGF were still high in stimulated muscles, but no longer different from controls with prazosin. After 3 to 4 days of treatment, capillary shear stress in resting muscle was 57% higher than in controls as a result of stimulation, but 4 times higher with prazosin.

Conclusions: Higher capillary shear stress with prazosin than with stimulation may upregulate VEGF expression in the early stages of treatment. Greater proliferation of capillaries preceding a higher proportion of VEGF‐positive capillaries in stimulated muscles, in the presence of a modest increase in shear stress, suggests that angiogenesis was initiated by other factors in addition to shear stress.
Relationship of Ultrafiltration and Anastomotic Flow in Isolated Rat Lungs
Authors: LIN WEN , HOGAN GENEVIEVE , EFFROS RICHARD M.
Published: January 2010

Objective: When arterial and venous pressures are increased to equal values in “stop‐flow” studies, perfusate continues to enter the pulmonary vasculature from the arterial and venous reservoirs. Losses of fluid from the pulmonary vasculature are due to ultrafiltration and flow through disrupted anastomotic (bronchial) vessels. This study compared the relative sites of ultrafiltration and anastomotic flows at low and high intravascular pressures.

Methods: Isolated rat lungs were perfused for 10 minutes with FITC‐dextran, which was used to detect ultrafiltration. Arterial and venous catheters were then connected to reservoirs containing radioactively labeled dextrans at 20 or 30 cm H2O for 10 minutes. The vasculature was subsequently flushed into serial vials, and ultrafiltration and vascular filling during the equal‐pressure interval were calculated.

Results: Ultrafiltration equaled 0.43 ± 0.11 mL at 20 cm H2O and was similar to the volume of fresh arterial and venous perfusate which entered and remained in the pulmonary vasculature during the equal‐pressure interval (0.45 ± 0.10 mL). At 30 cm H2O, 0.80 ± 0.23 mL entered and remained in the vasculature during the equal‐pressure interval, replacing the original perfusate, and calculated transudation (0.56 ± 0.09 mL) was not significantly more than at 20 cm H2O. Fluid also entered the airspaces at 30 cm H2O but not at 20 cm H2O.

Conclusions: At 20 cm H2O, flow through anastomotic vessels occurs at sites that are at the arterial and venous ends of the microcirculation. Flow in exchange vessels remains minimal, permitting measurements of ultrafiltration and exchange. Losses of perfusate from the pulmonary vessels complicate measurements of ultrafiltration at 30 cm H2O.
Valvular Density Alone Cannot Account for Sites of Chronic Venous Insufficiency and Ulceration in the Lower Extremity
Authors: AHARINEJAD SEYEDHOSSEIN , NEDWED STEPHAN , MICHLITS WOLFGANG , DUNN RAYMOND , ABRAHAM DIETMAR , VERNADAKIS ADAM , MARKS SANDY C.
Published: January 2010

Objective: Class 6 chronic venous stasis is associated with abnormal venous hemodynamics and ulceration. Ulcers primarily occur over bones and tendon prominences but very rarely over muscular compartments. We hypothesized that the anatomical distribution of venous stasis ulcers in the lower extremity is related to a lower density of venous valves.

Methods: The venous vasculature of six normal human legs was cast with resin, and their microvenous valvular anatomy was examined. Skin samples were obtained from the skin overlying the 1) Achilles' tendon, 2) anterior tibia, 3) medial malleolus, 4) lateral malleolus, 5) dorsal surface of the foot, 6) planta pedis, 7) dorsal aspect of the great toe; and from the skin regions overlying the 8) gastrocnemius, 9) tibialis anterior, and 10) peroneus muscles. The valvular and venous densities were determined in a scanning electron microscope, normalized to the size of specimens, and the valvular index was calculated. Analysis of variance with Bonferroni t‐test was used to compare the valvular index between the regions.

Results: Venous valves were observed in all tissue regions. The diameter of veins with valves ranged from 18 µm to 803 µm. The valvular index for regions overlying bones/tendons (i.e., regions 1–7) was significantly higher versus those overlying muscular regions (i.e., regions 8–10) (p < 0.05). The valvular index was not different (p = 0.51) when regions 1 and 2 (where ulcers almost never occur) were compared to regions 3, 4, 5, 6, and 7 (where ulcers frequently occur); nor were there differences between the vascular indexes of regions overlying muscle. The largest venous valves were observed in the plantar region, and the smallest‐sized ones were present in the peroneal region.

Conclusions: This study shows that the density of venous valves is actually higher in regions of the human lower extremity overlying bones and tendons, where venous stasis ulcers are common, than those overlying muscular areas, where ulcers are rarely seen. Thus, valvular quantity alone cannot account for the higher clinical incidence of ulceration. It is likely that muscular pumping and/or valvular quality are important factors in preventing the development of venous stasis and ulceration in the lower extremity.
Age‐Dependent Changes in the Postnatal Intestinal Microcirculation
Authors: NANKERVIS CRAIG A. , REBER KRISTINA M. , NOWICKI PHILIP T.
Published: January 2010

Significant changes occur in intestinal hemodynamics during the transition from fetal to newborn life and then again during the first postnatal month. Most importantly, basal vascular resistance substantially decreases following birth. It then decreases further between postnatal days 1 and 3, plateaus, and then begins a slow, progressive increase between postnatal days 12 and 30. The basal rate of intestinal blood flow mirrors the changes in vascular resistance in an inverse manner. The postnatal changes in vascular resistance appear to be mediated, in large part, by an increase in the constitutive and stimulated production of nitric oxide. Most importantly, the diameter of terminal mesenteric arteries (150–300 µm diameter) in newborn (i.e., 1 day old) swine is determined by three intrinsic vascular control systems: endothelial production of nitric oxide and endothelin, and the inherent myogenic response of vascular smooth muscle. In contrast, these vessels in older subjects (i.e., 35 days old) are primarily passive in nature and fail to demonstrate significant diameter change in response to blockade of endogenous nitric oxide production or endothelin receptors, or applied perturbations of pressure or flow rate. The circulatory physiology of the perinatal and newborn intestine is exceptional when compared to the adult condition inasmuch as several hemodynamic variables change quite dramatically between fetal and neonatal life and during the first postnatal month. The unique hemodynamic conditions that characterize the perinatal and newborn intestine appear to be part of the overall physiological transition that occurs as the fetus, once born, replaces the placenta with his gastrointestinal tract to obtain nutrition. The goal of this review is to describe the circulatory physiology of the perinatal and newborn intestine, with a particular emphasis on those portions of the intestinal microcirculation that have thus far been studied. First, however, it is important to discuss the age‐dependent changes that occur within the intestinal circulation during perinatal and early newborn life.
Land‐use and isolation interact to affect wetland plant assemblages
Authors: Boughton Elizabeth H. , Quintana‐Ascencio Pedro F. , Bohlen Patrick J. , Jenkins David G. , Pickert Roberta
Published: January 2010

Different management regimes imposed on similar habitat types provide opportunities to investigate mechanisms driving community assembly and changes in species composition. We investigated the effect of pasture management on vegetation composition in wetlands with varying spatial isolation on a Florida cattle ranch. We hypothesized that increased pasture management intensity would dampen the expected negative effect of wetland isolation on native species richness due to a change from dispersal‐driven community assembly to niche‐driven assembly by accentuated environmental tolerance. We used native plant richness, exotic plant richness and mean coefficient of conservatism (CC) to assess wetland plant assemblage composition. Sixty wetlands were sampled, stratified by three levels of isolation across two pasture management intensities; semi‐native (less intensely managed; mostly native grasses, never fertilized) and agronomically improved (intensely managed, planted with exotic grasses, and fertilized). Improved pasture wetlands had lower native richness and CC scores, and greater total soil phosphorus and exotic species coverage compared to semi‐native pasture wetlands. Increased wetland isolation was significantly associated with decreases in native species richness in semi‐native pasture wetlands but not in improved pasture wetlands. Additionally, the species–area relationship was stronger in wetlands in improved pastures than semi‐native pastures. Our results indicate that a) native species switch from dispersal‐based community assembly in semi‐native pastures to a species‐sorting process in improved pastures, and b) recently‐introduced exotic species already sorted for more intensive management conditions are primarily undergoing dispersal‐based community assembly. That land‐use may alter the relative importance of assembly processes and that different processes drive native and exotic richness has implications for both ecosystem management and restoration planning.
Clinical characteristics and outcome analysis of pediatric B‐cell non‐Hodgkin's lymphoma. Experience with FAB‐LMB 96 and UKCCSG B‐cell NHL guidelines in a developing country
Authors: AHMAD Naveed , ZAIDI Alia , BADAR Farhana , MAAZ Ata‐ur‐Rehman , AKRAM Muhammad S
Published: January 2010

Aim:  To analyze the clinical characteristics of B‐cell non‐Hodgkin's lymphoma (NHL) patients and the therapeutic efficacy of French‐American‐British Lymphoma Malins de Burkitt 96 and the recent United Kingdom Children's Cancer Study Group B‐cell NHL guidelines in the tertiary care hospital of a developing country.

Methods:  Patients aged ≤18 years registered at our hospital between January 1995 and December 2006 with histologically proved B‐Cell NHL were selected for retrospective analysis.

Results:  Of the total of 131 patients registered, 122 patients were eligible for evaluation. Of these 95 had Burkitt's lymphoma, 22 diffuse large B‐cell lymphoma and five had B‐cell NHL not otherwise specified. The mean age was 8.4 years. Overall 42 children had a baseline weight less than the 10th centile. A total of 37 had uric acid >10 mg/dl and 55 had a lactate dehydrogenase level >500; 73 had stage III and 31 had stage IV while only four presented at stage I and 14 at stage II. The abdomen was the commonest site of disease. A total of 45 patients died; 28 due to infection, nine due to tumor lysis syndrome and six of uncontrolled disease. All deaths occurred within an average of 35 days from starting treatment. Our 5‐year overall survival rate was 68 percent and our event‐free survival was 55 percent.

Conclusion:  Late presentation with advanced disease, poor nutritional status and high risk of exposure to infective agents all contribute to the high mortality in patients treated with intensive protocols in resource‐poor countries.
Social Justice and Social Determinants of Health: Lesbian, Gay, Bisexual, Transgendered, Intersexed, and Queer Youth in Canada
Authors: Dysart‐Gale Deborah
Published: January 2010

TOPIC:  While nurses address lesbian, gay, bisexual, transgendered, intersexed, and queer (henceforth LGBTIQ) patients' health needs, the professional nursing practice value of social justice provides a larger role for nurses in identifying and minimizing social barriers faced by LGBTIQ patients.

PURPOSE:  This paper examines the social and health‐related experiences of LGBTIQ youth in Canada, a country which has removed many of the social and legal barriers faced by LGBTIQ in countries such as the United States. An awareness of the Canadian LGBTIQ experience is instructive for nurses in different countries, as it reveals both the possibilities and limitations of social legislation that is more inclusive of LGBTIQ youth.

SOURCES:  Review of literature in PubMed, Academic Search Premier, government documents.

CONCLUSION:  The literature reveals that exclusion, isolation, and fear remain realities for Canadian LGBTIQ adolescents. The Canadian experience suggests that negative social attitudes toward LGBTIQ persist despite progressive legislation. The value of social justice positions nurses to constructively intervene in promoting the health and well‐being of LGBTIQ youth in the face of social homophobia.
. . . on Foster Care International Society of Psychiatric‐Mental Health Nurses
Authors: Galehouse Pam , Herrick Charlotte , Raphel Sally
Published: January 2010

PROBLEM:  Mental health problems are particularly widespread for foster children. There are approximately 700,000 youth in foster care and nonfamily settings in the United States. The mean entry age is 3 years. The average stay is 2 years. Experts estimate that between 30% and 85% of youngsters in out‐of‐home care have significant emotional disturbances. Foster care children represent 5% of Medicaid enrollees but use approximately 40% of Medicaid funds. A substantial number of these children have psychological problems so serious that they require residential placement. Adolescents living with foster parents or in group homes have about four times the rate of serious psychiatric disorders than those living with their own families (2009a). Despite this level of need, less than one‐third of children in the child protective system are receiving mental health services (2009a).

SOURCES:  Child psychiatric nurse advocates from the Association of Child and Adolescent Psychiatric Nurses Division of the International Society of Psychiatric‐Mental Health Nurses compiled this position statement for adoption by the Board of Directors as the Association's formal statement on the plight of children and adolescents in foster care.

CONCLUSIONS:  Areas that need to be addressed include (a) lack of consistent and comprehensive service planning; (b) communications across agencies and with the youth, their foster parents, and key stakeholders; (c) use of evidence‐based interventions to prevent and reduce the incidence of disability; (d) education of child welfare case workers about mental and emotional therapeutic management; and (e) education of foster parents and youth about mental health issues and appropriate treatments.
INTEGRATED QUALITATIVE/QUANTITATIVE TECHNIQUES FOR FOOD PRODUCT QUALITY PLANNING
Authors: PABLE ANANT , LU SUSAN , AUERBACH JOSHUA
Published: January 2010

Traditionally, food product manufacturers have used methods such as market research and sensory characterization for product quality planning. However, within the quality planning scope, the results of the quality planning methods have not been explored to explicitly translate into the manufacturing stage. This article presents the development of an advanced food product quality planning approach applied at the Black and White Cookie Company to translate customer requirements into manufacturing using integrated qualitative/quantitative techniques. The results showed that the method provided the manufacturer a good quantitative assessment of the product and process for addressing customer's needs, which are valid inputs for quality planning and the successful transition out of the planning phase. Also, the use of appropriate initial control charting during short runs in the preproduction stage verifies the process capability and stability. This was found especially effective for the food production system since the product feature variation is high, production is in small batches and data are of appropriate nature to fit the short‐run statistical process control charts. The approach can be further extended to integrate into the quality control and the improvement stages with more data available during those phases.

PRACTICAL APPLICATIONS

The proposed approach by this article will provide an integrated quantitative and qualitative tool for food manufacturing companies to improve the quality of their products at early quality planning stage.
ANTIOXIDANT PROPERTIES AND FRUIT QUALITY DURING LONG‐TERM STORAGE OF “ROCHA” PEAR: EFFECTS OF MATURITY AND STORAGE CONDITIONS
Authors: SILVA FILIPE J.P. , GOMES MARIA HELENA , FIDALGO FERNANDA , RODRIGUES JOSÉ A. , ALMEIDA DOMINGOS P.F.
Published: January 2010

Free radical scavenging activity and the content of ascorbic acid and glutathione were investigated during long‐term storage of the pear (Pyrus communis L. ‘Rocha’) fruit harvested at different maturity stages, stored in air or under controlled atmosphere and subjected to postharvest treatments with diphenylamine (DPA) and 1‐methylcyclopropene (1‐MCP). Harvest maturity had a significant effect on storage disorders, fruit firmness, soluble solids content and acidity. Differences in ascorbate content and free radical scavenging activity at harvest did not persist during storage. Controlled atmosphere and DPA strongly reduced the incidence and severity of browning disorders and superficial scald, whereas 1‐MCP provided the most effective control. Neither DPA nor 1‐MCP affected the free radical scavenging activity or the levels of ascorbate and glutathione in the pear. These results suggest that the benefits of 1‐MCP on internal breakdown are not directly related with its effects on the antioxidant levels and that, under good storage conditions, the antioxidant properties of the “Rocha” pear can be maintained for up to 8 months.

PRACTICAL APPLICATIONS

The importance of fruit antioxidant metabolites as beneficial phytochemicals has been widely recognized. Interestingly, the same metabolites are also essential for the health of the fruit itself. Thus, maintaining high levels of antioxidants in fruits throughout the supply chain is of utmost importance to maintain fruit quality and to deliver to consumers the health benefits of fruit consumption. Many studies have addressed fruit antioxidants, but these studies either report comparisons among fruit types analyzed at a single (often uncharacterized) stage of development or they study changes during short storage periods. European consumers have pears available all year round and the typical storage duration of European pears extends up to 8 months. Moreover, different storage regimes and several postharvest treatments that may impact fruit antioxidants are used in commercial practice. It is thus relevant to characterize pear antioxidants during long‐term storage and the effect of storage conditions and common postharvest treatments on fruit antioxidants. Harvest data are known to have a large effect on post‐storage fruit quality, but its effect on antioxidants during storage is unknown. This information is useful to nutritionists and consumers who have to choose fruit and to all involved in the fruit supply chain in order to provide fruit with better quality.
New records of Horipsestis kisvaczak László, Ronkay, Ronkay & Witt, 2007 (Lepidoptera: Thyatiridae) from China
Authors: ZHANG Feng‐Bin , HAN Hui‐Lin
Published: January 2010

Horipsestis kisvaczak László, Ronkay, Ronkay & Witt, 2007 is reported for the first time from China. The adult and genital characteristics of the species are briefly redescribed with illustrations. The available information including the distributional ranges and a key to the species are given.
Profession: A Useful Concept for Sociological Analysis?
Authors: ADAMS TRACEY L.
Published: January 2010

Il a toujours été problématique de conceptualiser les professions puisque les caractéristiques professionnelles varient beaucoup dans le temps et dans l'espace. Cet article analyse les façons selon lesquelles les professions et les occupations ont été délimitées historiquement dans la législation. Un regard sur la réglementation professionnelle de cinq provinces canadiennes antérieure à 1961 dénombre environ 36 groupes professionnels distincts. L'auteure croit qu'une meilleure compréhension s'appuyant sur la recherche empirique de ce qu'étaient les professions par le passé aidera à conceptualiser et à faire avancer la recherche actuelle sur les professions. Particulièrement importantes sont les considérations sur la qualité de même que sur la structure des relations d'emploi avec les autres groupes professionnels, le public et l'État.

Conceptualizing professions has traditionally been problematic because professional characteristics vary across time and place. This paper explores the ways in which professions and occupations were historically demarcated through legislation. A look at professional regulation in five Canadian provinces before 1961 reveals approximately 36 distinct professional groups. I argue that developing a more accurate, empirically based understanding of what professions were in the past will help us conceptualize and advance research on professions in the present. Particularly salient are considerations of status, as well as the structuring of occupations' relations with other occupational groups, the public, and the state.