bluuebunny/crossref_metadata_2025 huggingface dataset:
Foraging Strategies among Male and Female Marmosets and Tamarins (Callitrichidae): New Perspectives in an Underexplored Area
Authors: Box Hilary O.
Published: September 2008

Few studies have involved an examination of behavioural gender differences among callitrichid primates. The present paper presents consistent evidence from experimental projects, together with less formal observations, that adult females of both breeding and non-breeding status in species of marmosets (Callithrix) and tamarins (Saguinus) demonstrate priority of access to preferred and/or restricted sources of food. Differences in behavioural strategies between males and females in this regard are not only functionally plausible, but are consistent with differences in natural behaviour both in feeding ecology and social organization in species of the different genera. Behavioural propensities that relate to the behavioural strategies of males and females are also considered, together with a number of suggestions for future research that arise directly from the observations reported.
Autonomic Balance in Saimiri sciureus and Callicehus moloch: Relation to Life-Style
Authors: Mendoza Sally P. , Mason William A.
Published: September 2008

Previous research has shown heart rate to be substantially higher in squirrel monkeys (Saimiri sciureus) than titi monkeys (Callicehus moloch). In order to evaluate whether species differences in heart rate can be accounted for by contrasting patterns of autonomic activity, heart rate in response to novel test conditions was compared using standard pharmacological agents that selectively block the sympathetic (propranolol) or parasympathetic (atropine) components of the autonomic nervous system. Squirrel monkeys were found to exhibit greater sympathetic response to novelty than titi monkeys. In contrast, sympathetic activity in titi monkeys, but not squirrel monkeys, was quickly counteracted by a strong parasympathetic response. Intrinsic heart rates, estimated by blocking both parasympathetic and sympathetic input to the heart, were within the ranges of values predicted by body weight. Heart rate for titi monkeys stabilizes at intrinsic heart rate, whereas heart rate for squirrel monkeys is maintained well above intrinsic heart rate in a novel environment. The contrast between species in autonomic balance is consistent with and probably contributes to each species characteristic mode of interacting with their social and non-social environment.
Acute Kidney Injury after Transarterial Chemoembolization for Hepatocellular Carcinoma: A Retrospective Analysis
Authors: Park Jongha , Chung Hyun Chul , Lee Jong Soo , Lee Byeong Man , Kim Dong Min , Hwang Jae Cheol , Jo Min-Woo , Noh Maengseok , Shin Jung Woo
Published: September 2008

Background: Transarterial chemoembolization (TACE) for hepatocellular carcinoma (HCC) may result in acute kidney injury (AKI) like other angiographic interventions. Methods: To investigate the incidence, risk factor and outcomes of AKI after TACE, defined by Acute Kidney Injury Network (AKIN) criteria, we retrospectively analyzed 442 TACE treatment sessions in 236 HCC patients. Results: The incidence of AKI in the first 48 h after TACE was 9.8% (23 of 236 patients at risk). Presence of hypertension (OR 3.24, 95% CI 1.21–8.72, p = 0.02), lower baseline serum albumin (OR 0.29, 95% CI 0.15–0.56, p < 0.01) and higher creatinine level (OR 12.02, 95% CI 3.49–41.39, p < 0.01) were independent risk factors of AKI. Prolonged renal insufficiency after 1 month was observed in 24.1% of AKI episodes. Conclusion: AKI is a common complication after TACE and we have to pay attention to the prevention and early recognition of AKI occurrence in high-risk patients.
Pseudo-Intermittent Claudication
Authors: Verstraete M.
Published: September 2008

Intermittent claudication is caused by pain from an ischaemic muscle. Local tissue ischaemia is most often the result of an impairment of regional blood flow which is not a disease in itself but merely an event of a larger underlying disease which has to be searched for. Many conditions may induce complaints and clinical symptoms which simulate intermittent claudication but are of completely different origin. These conditions have been grouped in orthopaedic, neurologic, muscular, haematologic and metabolic disorders and were reviewed.
Rückenmarksmalacie und renale Atheromembolie als seltene Fernstörungen nach Aortenprothesen
Authors: Mairose U.B. , Eickhoff W.
Published: September 2008

This is a report about two cases of alloplastic transplantation of the aorta with complete different uncommon and remote complications. The first one died by an hypotonic-ischemic malacia of the spinal cord, the other one by repeated disseminated cholesterol microembolisms of the renal arteries followed by hypertonia and ischemic necrosis of the kidney.
Comparative Studies on the Chemistry and the Metabolism of Arterial and Venous Tissue
Authors: Kresse H. , Filipovic I. , Iserloh A. , Buddecke E.
Published: September 2008

Comparative studies of the chemistry and metabolism of human and bovine arterial and venous tissue had the following results (values for bovine tissue in parenthesis): 1. In arterial tissue the contents of collagen were 21% (37%) and of elastin 20% (31%) referred to the dry weight. In veins collagen amounted to 47% (30%) and elastin to 7% (18%). The mucopolysaccharide concentration was higher in arterial (1.2 and 1.5 resp.) than in venous tissue (0.4 and 0.2% resp.). Hyaluronate, chondroitin 6-sulphate (chondroitin 4-sulphate), dermatan sulphate and heparan sulphate were identified. In arterial tissue chondroitin sulphate was predominant with 59 % and 49 % resp. In human venous tissue the main component was dermatan sulphate (65%), in bovine veins it was hyaluronate (75%). No dermatan sulphate was found in bovine venous tissue. The number of cells was higher in arteries (4.5 × 107 nuclei/g w. wt.) than in veins (2.8 × 107). 2. On in vitro incubation bovine arterial tissue metabolized 73 %, venous tissue 32% of the added [U-I4C] glucose within 12 h. In this period 2.8 and 2.4 mg lactate resp./g wet tissue were formed by arteries and veins. The specific radioactivity of lactate synthesized in arterial tissue reached that of the added [U-I4C] glucose whereas lactate formed by veins had only 36 % of the specific activity of the [U-I4C] glucose. The specific radioactivity of the acid mucopolysaccharides was 5–6 times higher in venous tissue than in arterial tissue. After labelling with 35S-sulphate a 3-fold higher specific radioactivity of venous sulphated mucopolysaccharides was observed. 3. After incubation of bovine venous tissue in the presence of I4C-acetate the specific radioactivity of phospholipids was 45 % higher than that of arterial tissue in contrast to a 50 % lower labelling of cholesterol in venous tissue.
The Escape of the Renal Blood Flow Response During Sympathetic Nerve Stimulation
Authors: Johansson B. , Sparks H. , Biber B.
Published: September 2008

Response of renal blood flow to regional sympathetic nerve stimulation has been studied in anesthetized cats. When the sympathetic nerves to the kidney are stimulated at frequencies within the ‘physiological range’, renal blood flow first decreases markedly and then increases over the next 3 to 5 min to a value slightly below the control level. A similar ‘escape’ of the resistance response is found when the renal nerves are stimulated under conditions of constant flow. If the frequency of renal nerve stimulation is gradually increased the onset of the escape is greatly delayed, indicating that failure of impulse transmission or severe depletion of transmitter is unlikely to be the cause of the escape phenomenon. Intraarterial infusion of noradrenaline produces increased flow resistance with little or no subsequent escape showing that the escape cannot be attributed to loss of responsiveness of the vascular smooth muscle to the adrenergic transmitter. A quantitative decrease in the amount of transmitter released per impulse and intrarenal vascular control mechanisms related to blood flow autoregulation are discussed as possible causes of the escape phenomenon.
A Simplified Technique for Semiquantitative, Clinical Estimation of Serum β-and Pre-β-Lipoproteins
Authors: Srinivasan S.R. , Lopez-S. A. , Radhakrishnamurthy B. , Berenson G.S.
Published: September 2008

An important relationship exists between abnormalities of serum lipoproteins and atherosclerosis. A simple and reproducible system for a semiquantitative serum lipoprotein analysis is described and the determinations are sufficiently accurate for clinical use. The method is adaptable for laboratories without an ultracentrifuge and does not require elaborate equipment. The quantitative determination of serum lipoproteins complements serum cholesterol and serum triglycerides in evaluation of lipid abnormalities. The method can be used to study subtle abnormalities in ‘normal’ individuals as well as changes occurring in various disease states.
Blood Fibrinolytic Activity in Young Britons, Africans and Asians in Relation to their ‘Weight-for-Height’ Standard
Authors: Menon Sudhakaran
Published: September 2008

The blood fibrinolytic activity was studied in 93 volunteers belonging to 3 different racial groups and related to their body weight adjusted to the ‘weight-for-height’ standard. No difference was found in this activity when overweight, underweight and standard weight British and Asian males were compared. Increased blood fibrinolytic activity was observed in overweight African Negroes as compared to those of standard weight, and decreased blood fibrinolytic activity was discovered in underweight British women when compared to those of standard weight or overweight. It is suggested that the increased fibrinolytic activity in overweight African males may be due to their increased muscular bulk, since muscles are a potent contributor of plasminogen activator to the circulation.
Increased Permeability of the Blood-Brain Barrier Following Experimental Thermal Injury of the Skin
Authors: Basch A. , Fazekas I.Gy.
Published: September 2008

The authors produced 20% third-grade burns in rats. One, three and five days after, the animals were killed by decapitation and their cerebella examined by fluorescent and electron microscopic methods. It was observed studying both trypan blue and thorotrast techniques that the permeability of the blood-brain barrier was considerably enhanced even 5 days after burning of the skin. The opening of the so-called ‘tight-junctions’ between the endothelial cells could be observed. The possibility of the release of a vasoactive substance originating in the damaged tissues is discussed. This substance may be responsible for maintaining the longer period of increased permeability of brain capillaries.
Scanning Electron Microscopy of Aortic Endothelial Cell Boundaries After Staining with Silver Nitrate
Authors: Garbarsch C. , Christensen Collatz
Published: September 2008

Scanning electron microscopy of the rabbit thoracic aorta following staining with silver nitrate showed endothelial cell borders to be marked by zigzag lines outlining individual endothelial cells as oblong rhombic fields oriented with the long axis parallel to the aortic axis. The layer of endothelial cells coated an underlying layer of coarse longitudinal folds, probably foldings of the underlying elastic membranes. The individual endothelial cells were inconspicuous in uncoated specimens. Double coating with coal and gold revealed a grainy porous mass in the silver lines and a flat surface of endothelial cells studded with small round elevations. Comparative studies with transmission light microscopy and transmission electron microscopy indicated silver deposits in the endothelial cell boundaries. Fine dustlike silver sediments were also observed on the surface of endothelial cells and in the layers next to the intima.
The Role and Significance of Vasodilatation in the Development of Small Arterial Lesions in the Rat
Authors: Kóczé A. , Bálint A. , Nagy Z. , Hintalan A. , Jellinek H.
Published: September 2008

Repeated treatment with large doses of vasodilators elicited small arterial changes in rats. Similar lesions developed on alternate dosage of vasodilator and vasoconstrictor preparations. The mechanical strain imposed on the vessel wall by both types of vasoactive substances is believed to play a role in the pathomechanism of the vascular changes which seem essentially to arise from the impairment of the smooth muscle cells overburdened by forced movements of the vessel wall.
Response of Intrahepatic Vasculature to Isoproterenol and Epinephrine Infusions
Authors: Hanson K.M.
Published: September 2008

Response of hepatic arterial and intrahepatic portal venous vasculature to 10-min infusions of either isoproterenol or epinephrine was studied in 37 in situ dog liver preparations. Isoproterenol infusions at various dose rates (3.06–24.45 µg/min) were given by way of hepatic artery or portal vein. Hepatic arterial vasodilation, which was abolished by propranolol, was clearly evident while response of intrahepatic portal venous bed was incon sistent and not indicative of significant vasodilation. Arterial dilator response was attenuated later in the infusion period when isoproterenol was given at high dose rates. Femoral venous infusions of epinephrine (9.55 µg/min) resulted in a variable and slight hepatic arterial response while portal resistance was consistently increased. Following sotalol, epinephrine produced a marked increase in hepatic artery resistance in every case while intrahepatic portal venous resistance was increased to the same extent as before. It was concluded that both α-receptors (constrictors) and β-receptors (dilators) are present in canine hepatic arterial and mesenteric vessels while intrahepatic portal venous vasculature appears to possess few, if any, β-receptors.
Vergleichende biochemische Untersuchungen an einem autorhythmischen und einem nicht spontan aktiven Gefässmuskel in vitro
Authors: Voth D. , Lell D.
Published: September 2008

The purpose of the present study was to determine the relationship between biochemical parameters and the functional behaviour of an autonomously contractile and a non-contractile vascular smooth muscle (portal vein and vena cava inf. of the rabbit) in vitro. We studied the oxygen consumption and the utilisation of various substrates, the DNA content, the concentration of ATP, ADP and phosphocreatine, the extracellular space and the intracellular concentrations of Na+, K+ and Ca2+, the content of the iminoacid hydroxyproline and the microscopical characteristics of both vessels. The autonomously contractile portal vein differs definitely from the vessel without this functional speciality not only in regard to the fine structural and physiological characteristics but also to the metabolic behaviour and activity.
The Influence of Inflammation on the 125I-Fibrinogen Uptake Test in Experimental Thrombosis
Authors: Hladovec J. , Přerovský I. , Roztočil K.
Published: September 2008

The 125I-fibrinogen uptake test was used in rabbits after the production of thrombosis in the marginal ear vein. The uptake was very similar with thrombosis produced by irritants, thrombin as well as with inflammation without thrombosis. The 131I-albumin accumulated under these conditions to the same exten or even more than 125I-fibrinogen. The local increase of permeability seemed to represent the most important factor in the uptake of both 125I-fibrinogen und 131I-albumin.
Lymphostase und Vitamine
Authors: Földi M. , Földi-Börcsök Ethel
Published: September 2008

In the first part of the present work, experimental data are produced showing that a correlation does exist between lymphostasis and vitamins, both in connection with lymphoedema of the subcutaneous tissue and with lymphostatic increase of the permeability of the blood-brain barrier. In the second part, experimental data are discussed. A new theory is put forward which may be summarized as follows: If lymph drainage is unable to cope efficiently with an increased lymphatic load, fate of the oedematous area will be determined by the function of histiocytes. These elements of the reticuloendothelial system are able to incorporate and digest plasma proteins: they become colloidosmotically inactivated. Various vitamins increase this activity and, on the other hand, various vitamin deficiency states induce a decrease of this function.
Vascular Adjustments in Dilatory Reactions
Authors: Henrich H. , Singbartl G.
Published: September 2008

Dilatory responses of the isolated intestinal vasculature of the rat have been studied during constant infusion of acetylcholine (Ach), isoproterenol (IP) andmyotropic, i.e. Ca++ antagonistically acting doses of propranolol. The initial vasodilation was followed by a succeeding increase of flow resistance. This effect, called ‘escape phenomenon’ could constantly be proved during application of Ach, was dosedependent and reached a maximal escape quotient of nearly 30%. Large vasoconstrictive doses of Ach also showed an escape phenomenon indicating the probability of one basal mechanism causing the escape from vasodilation and vasoconstriction. Vasodilations evoked by infusion of IP and large doses of β-blockers showed escape reactions only in some cases. The discrepancy between the different escape behaviour can be understood by comparing the rate of development of the initial vasodilation, which was two times slower for IP and propranolol than for Ach. The escape from Ach-elicited vasodilations could be clearly reduced by myotropic acting doses of LB 46. These results demonstrate that the escape from vasodilation is not a drug-specific phenomenon but is of myogenic origin. The analogy of the escape from vasodilation and vasoconstriction suggests a common basal myogenic mechanism perhaps due to changes of Ca++-fluxes. Thus, the initial vascular reaction would represent an ‘overshoot’ and the escape an adjustment reaction in a ‘steady-state system’.
Autonomic Neuroreceptor Mechanisms in Brain Vessels
Authors: Owman C. , Edvinsson L. , Nielsen K.C.
Published: September 2008

Intracranial vessels are well innervated by both adrenergic and cholinergic nerves. They possess adrenergic and cholinergic receptors. A contractile response can be provoked by various amines, and noradrenaline can be released from the axons in the perivascular nerve plexus in amounts sufficient to induce strong vasoconstriction. The close relationship between adjacent perivascular cholinergic and adrenergic nerve terminals, also in the neuroeffector area, suggests axonal interaction. It is proposed that the autonomic innervation of brain vessels participates in the control not only of the cerebral circulation but also of associated intracranial pressure phenomena.
Inactivation of Endogenous Noradrenaline Released by Electrical Stimulation in vitro of Dog Saphenous Vein
Authors: Brandão F. , Guimarães S.
Published: September 2008

The present investigation was undertaken to study the inactivation of endogenous noradrenaline (NA) released by electrical stimulation of the dog saphenous vein strips. Electrical stimulation of this preparation caused contractile responses which were due to release of NA. Relaxation curves were determined after oil immersion. Cocaine (10–5 m) blocked the greatest part of the inactivation capacity showing that most of the released NA that acts on the α-adrenergic receptors is taken up by sympathetic nerves. Neither monoamine oxidase (MAO) nor catechol-O-methyl transferase (COMT) nor uptake2 seem to play important roles in the inactivation of endogenous NA. After blockade of neuronal uptake by cocaine, both cortexone (6 × 10–5 m), an inhibitor of uptake2, and U-0521 (10–4 m) (3,4-dihydroxy-2-methyl propiophenone), an inhibitor of COMT, blocked a significant part of the remaining inactivation capacity showing that uptake2 and COMT metabolism can represent an alternative to neuronal uptake. After cocaine, iproniazid (7 × 10–4 m) was ineffective. The relative roles of the different mechanisms of inactivation of endogenous NA are different from those for exogenous NA in the dog saphenous vein strips.
Electrical Properties and Constants of Longitudinal Muscle from the Avian Anterior Mesenteric Artery
Authors: Bolton T.B.
Published: September 2008

The electrical activity of longitudinal muscle of anterior mesenteric artery from domestic fowl was investigated with microelectrodes and in the sucrose-gap apparatus. Action potentials were recorded by both techniques. In the sucrose-gap each action potential preceded a phasic contraction and similar contractions were recorded in vivo suggesting that during life, action potentials are normally associated with the generation of tension. Measured with microelectrodes in hypertonic solution at 41 °C, the time constant of the muscle was 257 msec and the space constant 2.8 mm. The latter was unchanged when reducing the tem perature to 31 °C but the former was increased.
Age-Related Differences in Catecholamine Fluorescence of Human Vascular Tissue
Authors: Waterson J.G. , Frewin D.B. , Soltys J.S.
Published: September 2008

Vascular catecholamine fluorescence was studied in human gingival tissue obtained from subjects of different ages. An inverse relationship between fluorescence brightness and age was demonstrated. This finding was considered as possible evidence for a decline in direct sympathetic vascular control in older subjects, and its significance is discussed in the context of other age-related hanges in the sympathetic nervous system.
Systemic and Renal Hemodynamic Effects of Dopamine and Prostaglandin A alone and in Combination
Authors: Robie Norman W. , Goetter William E. , Goldberg Leon I.
Published: September 2008

Prostaglandin A (PGA) compounds infused intravenously at rates of 0.125, 0.25 and 0.50 µg/kg/min decreased mean aortic pressure and renal vascular resistance, but did not increase renal blood flow in pentobarbital-anesthetized dogs. In contrast, dopamine increased renal blood flow at infusion rates of 2.5, 5.0 and 7.5 µg/kg/min and increased mean aortic pressure at infusion rates of 5.0 and 7.5 µg/kg/min. With simultaneous infusions of PGA (0.125 and 0.25 µg/kg/min) and dopamine (2.5, 5.0 and 7.5 µg/kg/min), mean aortic pressure decreased and renal blood flow increased. In open-chest dogs, cardiac contractile force was increased more by dopamine than by PGA. Neither agent alone altered heart rate, but when administered together, heart rate increased. PGA (0.01–0.02 µg/kg/min) abolished the increase in blood pressure produced by larger doses of dopamine (15–20 µg/kg/min) without reducing the increase in renal blood flow. Thus, by varying infusion rates of dopamine and PGA, renal blood flow may be increased with no change, an increase or a decrease in arterial pressure.
Modification by Temperature of the Response of Isolated Aorta to Stimulatory Agents and Transmural Stimulation
Authors: Toda Noboru , Hojo Masakazu , Sakae Koichiro
Published: September 2008

Contractile responses of helically-cut strips of the rabbit aorta to drugs, ions and transmural electrical stimulation were compared at different temperatures of the bathing medium, the response at 37 °C being taken as control. The dose-response curve of norepinephrine was moved to the right and downward by lowering the temperature from 37 to 25 °C and by raising temperature to 40 °C. Responses to transmural neural stimulation at frequencies of 5 and 20/sec were attenuated at 25 °C, the attenuation being greater in the response at the lower frequency. Concentrations of exogenous norepinephrine needed to produce the same magnitude of contraction as that with transmural stimulation were markedly increased by lowering the temperature to 25 °C. Contractile responses to norepinephrine (2 x 10-6 m), histamine (2 × 10-5 m) and angiotensin II (10-7 m) were attenuated by 32–44% at 25 °C, whereas the responses to K+ (25 mil) and Ba++ (2 mil) were dependent on temperatures between 25 and 37 °C and were attenuated by 69 and 92%, respectively, at 25 °C. Contractures induced by Ca++ in K+-depolarized preparations exposed to Ca++-free media and also by Ba++ in preparations exposed to Ca++-free media varied directly by raising temperatures. Interference with the influx of divalent cations, such as Ca++ and Ba++, may be involved in the cold inhibition of aortic contractility.
Skeletal Muscle Vascular Volume Changes With Increased Venous Pressure
Authors: Baker Carleton H. , Menninger Richard P. , Schoen Robert E. , Sutton Truitt
Published: September 2008

Dog gracilis muscles were removed, enclosed in a plethysmograph and perfused at constant inflow pressure or constant inflow. Circulating blood volumes were measured by the constant infusion technique using RBC-51Cr or albumin-131l. Control venous pressure averaged 3 mm Hg and elevations (ΔPV) over the range of 5–40 mm Hg were produced. Volume changes were determined during and following ΔPV by plethysmography and by changes in total muscle radioactivity. Changes in total (amount of blood in the tissue), active (circulating), and mobilized vascular volumes were calculated. Active vascular volumes and total vascular volumes increased with venous pressure increments up to 25 mm Hg and then plateaued. Active vascular volumes (indicators) increased by amounts significantly greater than the increases in total vascular volume (plethysmography). Volume changes in the constant flow groups were double those in the constant pressure groups. The mobilized active vascular volume (active vascular volume change minus total vascular volume change) consists of a volume of blood contained in vessels unattainable by the indicators during the control period but which were made available to the indicator by the ΔPV. Mobilized vascular volume averaged 45% of the active vascular volume change. With venous pressure elevation there was an increase in the RBC-51Cr volume to albumin-131l volume ratio. This suggests a redistribution of red cells with respect to plasma, possibly resulting from reduced plasma skimming.
Collagen Metabolism during the Early Stages of Cholesterol-Induced Atherogenesis in Rabbits
Authors: Langner Ronald O. , Modrak John B.
Published: September 2008

The involvement of collagen in cholesterol-induced atherosclerosis in rabbits was investigated. Rabbits were fed a 2% cholesterol diet for 8, 16, 30, 60 and 90 days. Histological sections were taken and aortic free and esterified cholesterol were determined after separation on thin-layer chromatography. Prolyl hydroxylase activity was used as a measure of collagen synthetic rate and hydroxyproline levels as an estimate of collagen content. Cholesterol content was significantly increased after 8 days, while at this time there were no gross aortic lesions. After 30 days there was some aortic disease and by 60 days most of the rabbits exhibited pronounced aortic lesions. Histologically, the lesions consisted mainly of intimal foam cells. There was no alteration in collagen synthetic rate or content at 8, 16, 30 or 60 days. These data indicate that 60 days of continuous cholesterol feeding results in a foam cell aortic lesion with no alteration in collagen metabolism. After 90 days of cholesterol feeding there was a significant increase in collagen synthetic activity in the thoracic aorta. These data suggest that alteration of collagen synthetic activity is a seconadry response, resulting from injury induced by the aortic accumulation of large amounts of cholesterol.
Platelet Interaction with Human Umbilical Cord Vascular Basement Membrane
Authors: Gloster Elizabeth S. , Stemerman Michael B. , Spaet Theodore H.
Published: September 2008

The basement membrane of the human umbilical vein was studied by electron microscopy with respect to its ultrastructure, susceptibility to digestion by collagenase or trypsin, and reactivity with human platelets. Electron microscopic examination of this vessel showed a continuous reticulated basement membrane which morphologically resembled those of mammalian capillaries and rabbit heart valves. The vascular endothelium was removed by freezing and thawing, thus uncovering the underlying connective tissue. The vessels were sliced into rings which were incubated with collagenase or trypsin. The basement lamella appeared to be susceptible to digestion by either enzyme. Platelet interaction with exposed vascular basement membrane was studied by rotating frozen-thawed everted and non-everted rings in anticoagulated whole human blood. In heparinized or citrated blood, large aggregates of degranulated platelets adhered to collagenous controls; in contrast, the test rings with exposed basement membrane were partially covered with a monolayer of platelets which appeared to retain discoid or spherical shape and granules. In EDTA-anticoagulated blood, the collagen control rings accumulated a platelet monolayer, whereas little or no adhesion occurred on the basement membrane surface. In this system the basement membrane of the human umbilical vein appears to be a poor platelet reactive surface as compared to collagen.
Influence of Magnesium on Calcium- and Potassium-Related Responses in Vascular Smooth Muscle
Authors: Carrier, jr. Oliver , Hester Kelly , Jurevics Helga A. , Tenner. Jr Thomas E.
Published: September 2008

The influence of Mg on Ca- and K-related responses of rabbit aortic strips was studied. Aortic strips bathed in either a K-free or 60.0 mM K solution were less sensitive to Ca in the presence of 1.2 mM Mg. Ca induced greater maximum tension in the aortic strips in the presence of Mg when bathed in 60.0 mM K. Addition of K to a K-free medium induced a slight relaxation at low concentrations (<1.0 mM) which was Ca dependent. The relaxation was less in the presence of Mg. With Mg in the medium throughout the experiment (90 min), the threshold concentration of K, inducing a contractile response, was increased as was the maximum tension. Acute addition of Mg decreased the maximum response to K. When K was lowered from 5.4 to 0.0 mM a contractile response, absent in the presence of Mg, occurred. When the K was increased, the tension returned to baseline. At 25–30 mM K, the tension again increased, reaching a maximum at 40–50 mM K. 45Ca uptake was stimulated at all K concentrations producing a contraction. Mg depressed this increase in uptake. 45Ca efflux was more rapid into a 50.0 mM than into 0.0 mM K solution. Mg delayed 45Ca efflux. It is concluded from these data that Mg has two components in its effect on the Ca associated with K responses. One is a competition with Ca at extracellular sites probably at the membrane, and the other is intracellular, probably a competition with Ca at sequestration sites.
Standstill of Nailfold Capillary Blood Flow during Cooling in Scleroderma and Raynaud’s Syndrome
Authors: Maricq Hildegard R. , Downey John A. , LeRoy Carwile
Published: September 2008

Capillary blood flow in nailfold capillaries, observed continuously by capillary microscopy during standardized cold exposure (16 °C) has been compared in 15 patients with scleroderma (SD), 6 patients with Raynaud’s syndrome (RS) without known organic pathology, and 9 normal controls. Capillary microscopy affords direct observation of capillary blood flow and allows one to determine if standstill of capillary circulation occurs (as defined by the movement of the red blood cell column), a state impossible to differentiate from near zero flow by conventional methods. Complete standstill of capillary blood flow occurred in 10 of 15 patients with SD and in 1 of 6 patients with RS. Intermittent standstill was observed in 5 of 15 SD and in 4 of 6 RS patients. In all normal subjects and in 1 of 6 patients with RS the capillary blood flow continued throughout the cooling period. Thus all 15 patients with SD and 5 of 6 patients with RS could be distinguished from control subjects by the development of capillary standstill on cooling. It is concluded that capillary microscopy can separate SD and RS patients from control subjects during cold exposure and may be useful in early diagnosis and prognosis of rheumatic syndromes and in the evaluation of therapy designed to improve the nutritional capillary blood flow of the skin. Whereas the complete standstill of capillary blood flow appears to be definitely associated with pathology, the intermittent standstill pattern as defined in this study may be an exaggerated form of flow fluctuation also seen in normal subjects. A larger number of subjects will have to be studied to determine whether patients with RS of the vasospastic type without connective tissue disease can be distinguished from normal subjects with low finger blood flow rates in cold conditions.
Comparison of the Excitatory and Inhibitory Effects of Angiotensin and Vasopressin on Mammalian Portal Vein
Authors: Weston A.H. , Golenhofen K.
Published: September 2008

Angiotensin produced inhibitory and excitatory responses in guinea pig portal vein and excitatory responses in rabbit and rat portal vein. Vasopressin produced inhibitory responses in guinea pig and rabbit portal vein and excitatory and inhibitory responses in rat portal vein. In guinea pig portal vein, inhibition by angiotensin and vasopressin was associated with an increase in membrane potential which was, on average, smaller than that produced by isoprenaline, and with a suppression of spike discharges. Tachyphylaxis of the responses to angiotensin and vasopressin in portal vein was not observed and their effects were unaffected by tetrodotoxin, atropine and phentolamine plus propranolol.
Cyclic AMP and Protein Kinase in the Spontaneously Hypertensive Rat Aorta and Tissue-Cultured Aortic Smooth Muscle Cells
Authors: Sands Howard , Sinclair Diane , Mascali James
Published: September 2008

Cyclic AMP levels and protein kinase activity were determined in the aortas of rats with normotension, moderate and severe spontaneous hypertension. While the cyclic AMP levels were reduced in the aortas from rats with moderate and severe hypertension the protein kinase levels were found to be elevated only in the aortas from rats with severe hypertension. We have grown in tissue culture, aortic smooth muscle cells from the normotensive and severely hypertensive rat. Cultured cells from both strains have similar growth patterns and morphology. The differences seen in cyclic AMP and protein kinase levels in the intact aortas are also seen in the aortic smooth muscle cells in culture.
Density of Perivascular Nerves on Some Cerebral and Extracerebral Blood Vessels
Authors: Rosenblum William I. , Chen Melissa
Published: September 2008

The perivascular adrenergic nerves were counted as they crossed a grid-line superimposed on rat cerebral or femoral arteries and arterioles, and on the portal vein and its tributaries. The nerves were visualized with the formaldehyde-vapor, fluorescence technique. No support was received for the hypothesis that cerebral vessels are better innervated than extracerebral vessels. In fact, the density of nerves was significantly greater on the femoral and portal vessels than on the cerebral.
Uptake and Metabolism of Noradrenaline by the Mesenteric Arteries of the Dog
Authors: Garrett J. , Branco D.
Published: September 2008

Uptake and metabolism of tritiated noradrenaline by the mesenteric arteries of the dog and concomitant behaviour changes in endogenous noradrenaline are described. Posterior mesenteric artery strips were incubated for 30 min in Krebs solution containing (–)-7-3H-noradrenaline (1.084 µM); suitable pretreatments and/or preincubations were performed to study the influence of some drugs on these parameters. The arterial strips showed a high capacity to retain, accumulate and metabolize exogenous noradrenaline. At the concentration of noradrenaline studied, neuronal uptake and deamination represented the main inactivation mechanism, however, when neuronal uptake was blocked, extraneuronal deamination and o-methylation played a more important role. o-Methylation represented a vicarious enzymatic route when monoamine oxidase activity was inhibited. Iproniazid pretreatment increased markedly the endogenous noradrenaline content of the mesenteric arteries. During incubation with tritiated noradrenaline both an outflow of endogenous noradrenaline and an inflow of tritiated noradrenaline were observed.
Alterations in Calcium Transport and Binding by the Plasma Membrane of Mesenteric Arteries from Spontaneously Hypertensive Rats
Authors: Wei Jiann-Wu , Janis Ronald A. , Daniel Edwin E.
Published: September 2008

The effect of Sr++, Ba++ and Mn++ on calcium uptake by a plasma membrane-enriched fraction from mesenteric arteries of spontaneously hypertensive rats (SHR) was studied to determine what alterations in divalent cation interactions are associated with hypertension. 45Ca++ uptake in the presence of ATP by this fraction from SHR was significantly greater than that of normotensive rats (NWR). This 45Ca++ uptake by these fractions from both types of rat could be reduced by Ba++, Sr++ and nonradioactive Ca++, but not by Mn++; the ability of these cations to compete with 45Ca++ was in the following order Ca++ > Sr++ > Ba++. In contrast, 45Ca++ uptake in the absence of ATP by this subcellular fraction from SHR was significantly less than that of NWR, and this passive 45Ca++ binding could be displaced by Mn++ in addition to the other cations. Both qualitative and quantitative differences were found between SHR and NWR in this study of the effects of cations on calcium uptake by arterial plasma membrane. These results suggest that 1 This investigation was supported by the Alberta Heart Foundation and the Medical Research Council of Canada. 2 In this paper, calcium uptake is used operationally to describe all processes (binding, transport, etc.) leading to calcium accumulation, and calcium transport refers only to the process whereby calcium is transported actively across the vesicle membrane. 3 Dr. Janis was a Fellow of the Canadian Heart Foundation, and his present address is Department of Physiology, Northwestern University Medical School, Chicago, IL 60611 (USA). the plasma membrane of SHR arteries has calcium-binding and -transport properties that are different from those of NWR. However, there is not a complete correlation between the reported effects of the cations on contraction of other arteries in hypertension and on calcium uptake by membranes of SHR and NWR.
Uptake of 3H-Norepinephrine in Rabbit Mesenteric Blood Vessels
Authors: Su C. , Duckles S.P. , Florence V.
Published: September 2008

The uptake of tritiated norepinephrine in isolated rabbit mesoduodenal blood vessels was measured. Neuronal uptake was estimated utilizing the inhibitory effect of cocaine, and expressed on the basis of wet and dry tissue weights as well as circumferential area of the vascular wall. This area was presumed to approximate the area of the adrenergic nerve terminal plexus. The wet weight of smaller tissues was apt to be underestimated due to excessive drying during weighing; dry weight was more consistent over a wide range of tissue size. Either on the basis of weight or circumferential area, neuronal uptake in arteries increased as the diameter diminished, but uptake was practically constant in all segments of the veins. Arterial uptake per unit circumferential area was greater than in the accompanying veins, but this was not necessarily the case when uptake was expressed per unit weight. Neuronal norepinephrine uptake may be a useful index of adrenergic nerve density. On this basis it is suggested that the adrenergic neural vasoconstriction increases with decrease in diameter of both arteries and veins in rabbit mesoduodenum.
Elastin Fragmentation in the Pulmonary Artery of the Newborn Rabbit
Authors: Edgeworth Patricia , Roach Margot R.
Published: September 2008

Pulmonary arteries of rabbits aged 1 day to 2 months were distended at 44 mm Hg pressure and sectioned for study with the light microscope. Photographs were enlarged, and the frequency distributions of elastin lengths obtained at different ages. Maximum fragmentation occurred in the inner third of the artery, and was most marked at 3 weeks of age. No significant growth, or change in number of elastin lamellae occurred at this age. The fibres tended to be circumferential except in rabbits 4 weeks of age, where they were slightly helical.
Adrenergic Potentiation by Angiotensin II in Isolated Canine Cutaneous Arteries: Effect of Bathing Media and Calcium
Authors: Povolny Kathleen M. , Jung Richard W. , Kraft Edward , Zimmerman Ben G.
Published: September 2008

Contractions were elicited by field stimulation and norepinephrine in canine cutaneous arteries in Krebs-bicarbonate and Krebs-Tris media and the effect of angiotensin II, 1 × 10–7 m, on these responses was determined. The absolute magnitude of the field stimulation responses was much greater in the bicarbonate buffer. Angiotensin caused potentiation in both media of the responses to field stimulation and norepinephrine. In Tris buffer with 5 mM calcium the responses to field stimulation and norepinephrine were greater than in 2.5 mM calcium, however; the degree of potentiation caused by angiotensin was similar at both calcium concentrations. The angiotensin potentiating effect in vitro appears to involve a postsynaptic action of the polypeptide which is not affected by alteration of calcium concentration or the medium.
Thrombin-Induced Vasodilation in the Hindlimb (Dog)
Authors: Yonce Lloyd R. , Iatridis Panayotis G. , Joyner William L.
Published: September 2008

The objective of this study is to test the hypothesis that the vasodilation produced by intra-arterial injection of thrombin to the hindlimb of a dog may be caused by the secondary release or production of some vasodilating substance. The vasodilator response to thrombin was compared with the vasodilator response to acetylcholine, isoproterenol, histamine and serotonin before and after blockade with atropine, propranolol, phenergan or methyl-D-lysergic acid butanolamide (UML-491), respectively. Though the appropriate blocking agent blocked the vasodilator response to the respective drug, the thrombin-induced vasodilation was not blocked. These data support the hypothesis that thrombin-induced vasodilation is a response to the thrombin moiety.
Induction Angiometer
Authors: Kolin Alexander , MacAlpin Rex N.
Published: September 2008

It is possible to obtain continuous linear recordings of changes in vascular diameters on the basis of the electromagnetic induction principle. An extracorporeal coil energized by an alternating current generates an AC magnetic field and acts as a transformer primary. An intravascular loop of fine wire acts as transformer secondary. The EMF induced in the loop is proportional to the diameter of the vessel which confines the loop. Relative measurements do not require a calibration. Absolute measurements require radiographic determination of vessel diameter. Changes of less than 0.1% in vascular diameters can be easily recorded. Variations in pulsatile diameter changes as well as pharmacologically induced changes in mean diameter have been studied.
Effects of Ascorbic Acid and its 2-Sulfate on Rabbit Aortic Intimal Thickening
Authors: Verlangieri A.J. , Hollis T.M. , Mumma R.O.
Published: September 2008

Effects of intravenously injected L-ascorbic acid or L-ascorbic acid 2-sulfate on aortic intimal thickening were examined histologically, qualitatively, and quantitatively in the upper, middle and lower thoracic aortic positions of cholesterol-induced atherosclerotic rabbits. A means of evaluating the degree of pathology of the aortic positions was developed employing five descriptive statistics of intimal thickening. Both L-ascorbic acid and L-ascorbic acid 2-sulfate inhibited intimal thickening. The most significant reductions were observed in the upper thoracic aorta.
Absence of Renal Circulatory Autoregulation during Perfusion with Paraffin Oil
Authors: Aizawa Chikara , Waugh William H.
Published: September 2008

Autoregulation of vascular flow as a function of arterial pressure was studied in isolated dog and rat kidneys, perfused serially with an oxygenated aqueous colloidal medium and with oxygenated paraffin oil. Square wave elevations in arterial pressure elicited autoregulatory adjustments in flow within the first few seconds of elevated pressure during colloidal perfusion but not during oil perfusion of the same kidneys. Before oil perfusion, the steady state autoregulatory efficiency ratios (% flow change/% pressure change) over pressures ranging from 95 to 180 mm Hg averaged 0.3710.13 and 0.51 ± 0.16 (mean ± SD) in dog and rat kidneys, respectively. During oil perfusion, the autoregulatory efficiency ratios exceeded 1.0 in every instance. Following oil perfusion, vasoactive autoregulation of colloidal perfusate flow returned, at very low organ flows. Our results do not confirm the previous findings of Leichtweiss, Schroder, and Weiss [Pflügers Arch. ges. Physiol. 293: 303 1967] concerning the presence of autoregulation during oxygenated renal oil perfusion. Our findings suggest that renal circulatory autoregulation is either primarily myogenic or else primarily dependent upon a rapidly acting tubulovascular feedback mechanism.
Resolution of Lipid-Containing Atherosclerotic Lesions Induced by Injury
Authors: Moore Sean , Friedman Robert J. , Gent Michael
Published: September 2008

In previous experiments, injury-induced atherosclerosis has been shown to be associated with the development of fatty streaks. The findings suggested that fatty streaks might represent a stage in healing of intimal injury evolving to fibrous plaques, free of lipid. The present experiment was designed to study the incidence and evolution of these lesions during a 2-week period of lesion retrogression following removal of a catheter placed in the aorta for 1 week. The findings indicate that as fat-containing lesions, either of the thromboatherosclerotic or fatty streak varieties, decreased, the amount of nonlipid-containing fibrous lesions increased.
Effects of Prolonged Hemorrhagic Hypotensive Stress on Catecholamine Concentration of Mesenteric Blood Vessels
Authors: Lombard J.H. , Loegering D.J. , Stekiel W.J.
Published: September 2008

Norepinephrine (NE) and epinephrine (E) concentrations were determined fluorometrically as an index of functional adrenergic innervation in small mesenteric arteries, veins, and superior mesenteric arteries of dogs and rats subjected to a period of prolonged hemorrhage at a constant mean arterial pressure of 35 mm Hg. In nonhemorrhaged animals, highest catecholamine concentrations were found in the small principal arteries, next highest in the small veins, and least in superior mesenteric arteries. A significant decrease occurred in the NE and E concentrations of all three vessel types in the dog during the decompensatory phase of the hypotensive stress (defined as the hypotensive period beyond the time at which maximum bleedout volume occurred). In the rat significant decreases were detectable only in the NE concentrations of the small arteries and veins during this phase. It is concluded that the increase in neurogenic vascular tone accompanying severe hemorrhagic stress is lost simultaneously on the arterial and venous sides of compensatory vascular beds. Such loss is closely related to transmitter depletion at the adrenergic neuromuscular junction and, if allowed to continue uncorrected, can contribute significantly to irreversible cardiovascular collapse.