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PubMed1998

How to stay cool in a hot desert--a lesson from the rock pigeon.

This review presents an overview of the puzzle called "cutaneous water evaporation (CWE) cooling mechanism" in birds. Heat acclimation of the rock pigeon induces cellular modifications that affect the myocardium, cutaneous vasculature, and the epidermis, and hence enable the initiation of CWE. These cells are the targets for adrenergic signals that participate in the mechanism that controls the initiation and intensity of CWE. As a result the cardiac performance of the heat acclimated pigeon is intensified in response to adrenergic agents, and peripheral blood vessels and the epidermis both increase their permeability in response to heat stress. The CWE cooling mechanism is more economical in terms of water conservation, and provides more efficient protection to its owner, compared to the 'classic' respiratory cooling mechanism. Moreover, current data present the rock pigeon--a small diurnal homeotherm--as a classic model for a desert bird.

Adaptation, Physiological↗
PubMed1981

[Effects of local vibration exposure on the finger blood flow (author's transl)].

The purpose of the present study was to clarify the physiological response of peripheral blood vessels when some vibrational stimuli were given to five healthy young men (21-22) continuously and intermittently. The vasoreaction was observed on each subjects after the exposure to vibration at frequencies 18, 32, 64 and 125 Hz with acceleration level at 5 g (peak value). In the pulse wave height of left and right arms, a specified tendency was not found while a larger variation was observed. After continuous exposures, pulse wave propagation velocity at the left arm showed a decreasing tendency at lower frequencies, but in the right arm, such a tendency did not appear. After intermittent exposures, it showed decreasing tendencies at both the left and righ arms, but such remarkable decreases were not observed as was seen at the left arm after continuous exposure. Variation analysis on the pulse wave showed that the propagation velocity was related significantly (p less than 0.01) to the subject and to the frequency during continuous and intermittent exposures of the left and right arms. These results indicate that the lower frequency is one of the factors which cause the vibrational disease, and there was a person who is liable to vibrational disease. When compared with the intermittent vibration exposure, the continuous vibration exposure produced significantly lower pulse wave propagation velocities in the left arm. This finding indicates that the intermittent vibration relieves an accumulation of the effects by vibration.

Adult↗
PubMed1982

A scanning electron microscopic study of leukocytes and their interaction with bacteria in human periodontitis.

Shape, size, topographical relationships, surface morphology, phagocytosis and locomotion were used to identify and study leukocytes in human cases of periodontitis. These cells were described in the following locations: in peripheral blood vessels adjacent to the pocket epithelium; gingival connective tissue; basement lamina; sectioned pocket epithelium; surface of pocket epithelium; junctional epithelium; and cementum surface. The interaction of leukocytes and bacteria was documented in the phases of recognition, attachment and engulfment of bacteria. Morphologic data suggesting the process of degranulation was also presented.

Bacteria↗
PubMed1998

Transplantation of Fu/HC-incompatible zooids in Botryllus schlosseri results in chimerism.

The colonial urochordate Botryllus schlosseri undergoes a genetically defined, natural transplantation reaction that is controlled by a single Mendelian locus (called the Fu/HC). This Fu/HC-based allorecognition system is initiated when peripheral elements of the vasculature interact on the edges of two asexually expanding colonies. To better understand the spatial organization of the cellular elements responsible for Fu/HC-based allorecognition, we bypassed the normal site of interaction (the ampullae) and experimentally transplanted zooids between Fu/HC-noncompatible Botryllus schlosseri pairs. The results show that (1) instead of the expected rejections (tissue necroses) that develop after natural contacts between peripheral blood vessels, the transplanted organs are morphologically eliminated within a few days in conjunction with the normal blastogenic cycle; and (2) donor-recipient chimerism is established after complete morphological elimination of transplanted tissues. These results suggest that Fu/HC-based allorecognition responses in Botryllus schlosseri occur exclusively at the ampullae and that once cells have crossed this barrier, they are able to survive and proliferate in the new host colony.

Animals↗
PubMed1987

Intra-arterial mitomycin C treatment of unresectable liver tumours. Preliminary results on the effect of degradable starch microspheres.

Regional chemotherapy might be more efficient if the cytostatic drug is injected together with degradable starch microspheres (DSM), which induce temporary blockage of arterioles and trap the co-injected drug in tumour. Eighteen patients with non-resectable liver cancer were included. Mitomycin C (15 mg/m2) was injected intra-arterially mixed with 900 mg of DSM every six weeks. For estimation of the effect of DSM in the liver a radiolabelled tracer was injected via the same route. Its passage through the liver to the systemic circulation was continuously measured by a detector situated over peripheral blood vessels. The effect of DSM on the tracer passage varied considerably between different patients. The study also indicated opening of new vascular pathways some minutes after the initial injection. The dose of DSM for total blockage of the arterial blood flow, indicated by angiography, also varied. In some patients 540 mg induced total occlusion. In others neither angiographic nor tracer passage were affected by the microspheres although 900 mg (or even more) were injected. Factors such as size of the vascular bed, portal and arterial blood flow and arterio-venous shunting seemed to be of great importance and should be controlled in order to optimize the use of DSM in conjunction with chemotherapy of liver tumours.

Female↗
PubMed1983

Effects of chronic arachidonate on blood pressure of spontaneously hypertensive rats.

Three weeks of treatment with arachidonic acid (250 mg/kg/day, s.c.) produced an antihypertensive effect in 16 week-old spontaneously hypertensive rats (SHR) as compared with vehicle treated rats. Indomethacin (4 mg/kg, s.c. B.I.D.), given concurrently with arachidonate, abolished the antihypertensive effect. Plasma catecholamines were not altered by the arachidonate treatment, but blood pressure increments after spinal cord stimulation or after intravenous administration of norepinephrine and angiotensin II in the pithed rat were diminished. Increments in plasma catecholamines in response to spinal cord stimulation were similar in both groups of pithed rats. These data demonstrate the antihypertensive effect of arachidonic acid in SHR with established hypertension. This beneficial effect seems to be mediated through cyclooxygenase metabolites, and might be related to reduced responsiveness of peripheral blood vessels to pressor stimuli.

Angiotensin II↗
PubMed1991

Evidence against leukotrienes as mediators of brain edema.

Leukotrienes are powerful metabolites of arachidonic acid which are known to increase the permeability of peripheral blood vessels. These substances are found in brain tissue in association with cerebral ischemia, and in brain tumors. Therefore, it has been proposed that leukotrienes have a mediator function in brain edema. This hypothesis was subjected to further experimental analysis in this study, in which the authors investigated whether: 1) superfusion of the exposed brain surface with leukotrienes increases the permeability of extraparenchymal blood vessels in vivo; 2) intraparenchymal infusion of leukotrienes induces brain edema; and 3) pharmacological inhibition of leukotriene formation by BW755C, an inhibitor of leukotriene synthesis, reduces formation of brain edema from a standardized traumatic insult. The pial vessels of the parietal cortex of cats were examined by fluorescence microscopy during cerebral superfusion with the leukotrienes C4 (LTC4), D4 (LTD4), or E4 (LTE4) by using an open cranial window preparation. Intravenous Na(+)-fluorescein served as an in vivo blood-brain barrier (BBB) indicator. Superfusion of the pia with leukotrienes (up to 2 microM) did not open the barrier to fluorescein, but was associated with a significant constriction (up to 25%) of arterial and venous vessels. In experiments with slow infusion of leukotriene B4 (LTB4) or LTC4 into the white matter of feline brain, the tissue water content was subsequently determined in serial brain slices using the specific gravity method. Tissue water profiles obtained after a 15-microM infusion of either LTB4 or LTC4 were virtually identical with those of control animals infused with mock cerebrospinal fluid. Thus, neither LTB4 nor LTC4 led to an augmentation of infusion-induced brain edema. In a final series, a cold lesion of the left parietal cortex was induced in rabbits. Twenty-four hours later, swelling of the exposed hemisphere was quantified by gravimetrical comparison of its weight with that of the contralateral nontraumatized hemisphere. Eight animals received BW755C intravenously prior to and after trauma to inhibit formation of leukotrienes. Seven rabbits were infused with an equivalent volume of saline as a control study. The resulting hemispheric swelling was 7.7% +/- 0.6% (mean +/- standard error of the mean) 24 hours later in animals receiving BW755C and 7.8% +/- 1.2% in the control group, indicating that inhibition of leukotrienes was ineffective in preventing formation of vasogenic brain edema. The findings demonstrate that leukotrienes administered to the brain in concentrations occurring under pathological conditions do not open the BBB nor do they induce brain edema.(ABSTRACT TRUNCATED AT 400 WORDS)

4,5-Dihydro-1-(3-(trifluoromethyl)phenyl)-1H-pyraz↗
PubMed1999

[Effect of vasodilators on femoral-to-radial arterial pressure gradient after cardiopulmonary bypass].

In 57 adult patients undergoing valve replacement surgery or valve plastic surgery, pressure gradient between the femoral and radial artery was evaluated after cardiopulmonary bypass (CPB). During CPB, the rectal temperature was kept at mild or moderate hypothermia. Nitrates and prostaglandin E1 were administered in all patients during operation. Patients were divided into two groups; Group A of 31 patients who had history of hypertension and received some vasodilators up to the operation, and Group B of 27 patients who had no history of such medication. There was no difference in patient's characteristics, anesthetic time, CPB time and aortic cross clamping time between the two groups. There was a significant difference between the pre-CPB and post-CPB in hematocrit data. Systemic vascular resistance (SVR) decreased significantly from the pre-CPB level to the post-CPB level. There was no significant difference between Group A and Group B in SVR, but a higher femoral-to-radial artery pressure gradient was observed in Group A until the end of operation. Hypertension and the use of vasodilator change the tone of peripheral blood vessels and intensify femoral-to-radial artery pressure gradient after CPB.

Aged↗
PubMed1999

5-Hydroxytryptamine(1A) receptor activation enhances norepinephrine release from nerves in the rabbit saphenous vein.

Although serotonergic receptor agonists are known to modulate release of central serotonin, less is known about the ability of serotonin to alter neurotransmission in peripheral adrenergic nerves. The present study used field stimulation (40V, 0.7 ms duration, 1-16 Hz) to contract the rabbit saphenous vein, an effect that was abolished in the presence of tetrodotoxin and prazosin (10(-6) M), consistent with stimulation of neuronal norepinephrine release. Furthermore, the field-stimulated contraction was not altered by the 5-hydroxytryptamine (5-HT)(1B/1D) receptor antagonist GR127935 (10(-6) M), but was markedly inhibited by the 5-HT(1A) receptor antagonist WAY 100635 (10(-6) M). GR127935 (10(-8) M) inhibited contraction to sumatriptan, documenting that the concentration used was sufficient to block 5-HT(1B/1D-like) vascular receptors in this tissue. Likewise, WAY 100635 (10(-6) M) inhibited contraction to the 5-HT(1A) receptor agonists (+/-)-8-hydroxydipropylaminotetralin hydrobromide (8-OH-DPAT) and LY238729, without altering contraction to norepinephrine or sumatriptan. Furthermore, both 8-OH-DPAT and LY228729 enhanced the contractile response to field stimulation (1. 0-8.0 Hz) and activated norepinephrine release in the absence of field stimulation. Contractile responses of the rabbit saphenous vein to both 5-HT(1A) receptor agonists were markedly inhibited by prazosin and dextrally shifted by WAY 100635, supporting the idea that the 5-HT(1A) receptor agonists were activating presynaptic 5-HT(1A) receptors to enhance norepinephrine release even in the absence of field stimulation. Thus, in the rabbit saphenous vein, 5-HT(1A) but not 5-HT(1B/1D) receptors enhanced neurotransmitter release from adrenergic nerves. These observations suggested that serotonergic nerves or other cell types in the saphenous vein are activated by field stimulation to release serotonin, which in turn activates presynaptic 5-HT(1A) receptors on adrenergic neurons to effect norepinephrine release. To support this hypothesis, serotonin levels were measured in the saphenous vein and were increased after pargyline pretreatment (30 mg/kg s.c.), decreased after dl-p-chlorophenylalanine methyl ester pretreatment (300 mg/kg s.c.), and unaltered after pretreatment with 6-hydroxydopamine hydrobromide (100 mg/kg s.c.). Thus, we provide strong evidence for the 1) presence of serotonin and its direct synthesis independent of adrenergic nerves and 2) a novel excitatory effect of presynaptic 5-HT(1A) receptor activation on adrenergic nerves in a peripheral blood vessel.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1999

[The application of end user computing (EUC) for detection of lipoprotein lipase gene abnormality].

Lipoprotein lipase (LPL) is an enzyme digesting lipoprotein triglyceride (TG) in peripheral blood vessels. Most patients with LPL deficiency show very high plasma TG and low HDL-C. To establish an effective computer-based screening system to identify individuals with genetic LPL disorders, we selected 50 subjects whose plasma TG was over 350mg/dl and HDL-C was lower than 35mg/dl from patients at Hamamatsu University Hospital. We applied End User Computing (EUC) of our laboratory system to select high risk subjects with LPL gene abnormalities. Polymerase chain reaction (PCR) products from LPL gene exons 2-9 were screened by single-strand conformation polymorphism (SSCP), direct DNA sequence analysis and restriction fragment length polymorphism (RFLP). We found a novel missense mutation (1223C-->G, S323C) in LPL gene exon 7 from three subjects. By PCR-mediated site-directed mutagenesis and restriction digestion, the three subjects were found to be heterozygous. In addition, we identified two other common mutations in Japanese employing the RFLP method. One was the 1595C-->G (S447X) in exon 9 from six subjects, two homozygous and four heterozygous individuals. The other was a mutation of intron 3 (C-->T transition) from four heterozygous subjects. Using EUC screening method, we detected genetic LPL abnormalities more easily. The frequency of the LPL gene mutation in the 50 high-risk subjects was 26%, and was estimated to be one out of 2,000 patients at our clinic. Using the EUC system to screen for LPL mutations was established to be an effective computer-based screening system to identify individuals with genetic abnormalities.

Adult↗
PubMed2000

Vasodilation in human subcutaneous arteries induced by neuropeptide Y is mediated by neuropeptide Y Y1 receptors and is nitric oxide dependent.

Neuropeptide Y (NPY) is known as a potent vasoconstrictor of peripheral blood vessels both in vivo and in vitro. There have been reports suggesting that NPY also has a dilatory effect. The aim of the present study was to elucidate whether NPY dilates small human subcutaneous arteries. Subcutaneous arteries, obtained from patients undergoing abdominal surgery, were mounted in in vitro tissue baths, and the vascular responses to NPY were investigated. The presence of mRNA encoding the human NPY Y1 receptor in endothelial cells from human umbilical veins was studied by the use of reverse transcriptase - polymerase chain reaction (RT-PCR). In arteries precontracted with the prostaglandin analogue U46619, NPY induced a concentration-dependent vasodilation (Emax 30 +/- 10% of the U46619-induced contraction), which was significantly inhibited by the NPY Y1 receptor antagonist BIBP3226 (1 microM), causing a rightward shift of the concentration-response curve, pEC50 7.1 +/- 0.3 vs. 7.7 +/- 0.3 for NPY alone. After pretreatment with the nitric oxide synthetase inhibitor N(G)-nitro-L-arginine methyl ester (L-NAME) (10 microM), the dilation was abolished (Emax 6 +/- 5% of the U46619-induced contraction). mRNA encoding the human NPY Y1 receptor was detected in endothelial cells from human umbilical veins. It was concluded that NPY induces vasodilation in human subcutaneous arteries. The dilation is mediated via the NPY Y1 receptor and is dependent on nitric oxide.

Arginine↗
PubMed2001

[Can minimal arterial aggressions using non-penetrating mechanical clip suture prevent myo-intimal hyperplasia? Preliminary results].

SUBJECT: Vascular anastomosis is still associated with a significant rate of early (stenosis, thrombosis) and delayed (intimal hyperplasia) complications. Even though suture closure remains the most widespread standard procedure, many mechanical systems have been developed mostly using non penetrating clips, aiming to make the suture easier, to reduce the operating time and to reduce the scarring process of the arterial wall. We investigated the usefulness of non penetrating titanium Vascular Closure Staple (VCS) developed for peripheral blood vessels anastomosis, in a study on 20 rabbits with the small VCS system. MATERIAL AND METHODS: On 20 rabbits, 9 of the aortic sutures were done with VCS clips and 11 were done by standard closure. RESULTS: We found a significant improvement in the operating time of the closure (9 +/- 2 minutes versus 14 +/- 4 minutes), early and delayed (10 weeks) patency and the respect of the aorta diameter (0.248 +/- 0.01 centimetres versus 0.246 +/- 0.039 centimetres) and loss of surface (40.3 +/- 5.59% versus 45.6 +/- 6.34%). The main improvement is the reduced intimal hyperplasia (0.128 +/- 0.05 millimetres versus 0.198 +/- 0.032 millimetres. P=0.012). CONCLUSION: Arterial closure can be performed more rapidly with VCS clips than with suture closure, and with a marked reduced reaction of intimal hyperplasia. With those elements it is necessary to continue the experimental studies and to evaluate the VCS sutures at mean and long term.

Animals↗
PubMed1998

Effects of an artificially carbonated bath on athletic warm-up.

The effects of an artificially carbonated bath (36 degrees C, CO2 300 ppm, 20 minutes) on the warm-up of swimmers was compared with those of a freshwater bath (36 degrees C, 20 minutes). Carbon dioxide is reported to have a vasodilatory effect on peripheral blood vessels of cutaneous and muscular tissue and to promote blood flow. We observed that the warm-up effects of a carbonated bath before swimming on the hematocrit, white blood cell, total plasma protein, and total cholesterol levels in venous blood were significantly increased more than those of a freshwater bath before swimming in recovery period (p < 0.05). Thus the carbonated bath tended to be more effective for increasing the concentrations of blood components. In the recovery period, the carbonated bath before swimming also resulted in significantly smaller changes in blood lactic acid and heart rate than those of a freshwater bath before swimming (p < 0.05). The decrease in electromyography of the M. rectus femoris during swimming suggested more efficient muscle activity after a carbonated bath. Therefore after a carbonated bath, swimmers should have a higher reserve left in the cardiovascular system, resulting in better performance during swimming and less accumulation of fatigue-related metabolites after swimming.

Adolescent↗
PubMed1975

Renal hypertension.

Continuing interest in the mechanism of hypertension have produced considerable new information on the underlying pathophysiologic processes involved. Elucidation of the role of renal malperfusion, the renin-angiotensin-aldosterone mechanism, and renal medullary antihypertensive substances continues to clarify our understanding of renal hypertension. Current evidence suggests that angiotensin can produce hypertension by a direct effect on peripheral blood vessels in malignant hypertension and in renin-secreting renal tumors and by an intrarenal mechanism influencing intrarenal distribution of blood flow, and, thereby, sodium resorption in chronic renovascular hypertension. The current diagnostic techniques used to determine the presence of renal atery stenosis and its functional significance are reviewed. Arteriographic evidence of renal artery collaterals and a positive differential venous renin ratio are the two parameters whose usefulness and practicality have been best documented in recent years. The results of surgical procedures reported in the world literature show a 50 per cent rate with a further 30 per cent improvement rate in terms of control of hypertension. When functional significance of stenosis is demonstrated before surgical procedures, cure rates of the order of 80 per cent can be achieved. Recent developments of technique of operating room upon less extensive lesions of the renal artery branch extend the possibilities of surgical benefit which should also be considered in the presence of renal failure of renovascular origin.

Aldosterone↗
PubMed2002

[Neosynephrine mydriasis combined with general anesthesia with halothane in ocular surgery].

Ophthalmologic surgical interventions are performed in numerous cases under general anaesthesia with halothane, many of which requiring a preoperatory mydriasis. Neosinerfin is alpha-adrenoceptive sympathomimetic. Local use, in a 10% concentration produces a strong mydriasis, resistant to the opening of the aqueous chamber during the intervention. Its systemic effects are remarkable: it induces a peripheral blood vessel constriction which can unleash a reflex bradycardia followed by a shortcoming of the cardiac flow. The halothane has various effects upon the heart: reduces the cardiac frequency, reduces the conduction speed of the cardiac impulse stimulating rhythm disorders, sensitizes the myocardium to the action of adrenaline, diminishes the heart's contraction force and the cardiac flow. The cumulative effects of seosinefrin and halothane cause major cardio-vascular changes: sinus bradycardia, ventricular arrhythmia, arterial hypotension. These are reasons for which the pre- and intraoperatory use of neosinefrin is unadvisable. Under this circumstances the collaboration between the ophthalmologist and anesthesiologist is very important, each of them having specific tasks. The ophthalmologist: preoperatory, the optimal pupillary dilatation may be obtained with tropicamide and diclofenac 0.1%, preoperatory, if the general anesthesia must be combined with local anesthesia, anesthetics in association with adrenalin should not be used; immediately postoperatory local use of atropine should be applied with cautiousness. The anesthesiologist: preoperatory he will not interrupt anti-hypertensive, anti-arrhythmia, anti-angina medication, with the mention that adrenoceptive alpha blockers (Prazosin) are indicated in comparison to adrenoceptive beta blockers because they diminish the risk of rhythm disorders; the use of clonidine and avoiding of phenobarbital in the premedication of the patient. As far as it is possible, it is recommended that halothane is replaced with izofluran or enfluran or enfluran which have a great tolerance to exogenous adrenoceptives.

Adrenergic alpha-Agonists↗
PubMed2003

[Early effects of cigarette smoking in hypertensive and normotensive subjects. An ambulatory blood pressure and thermographic study].

BACKGROUND: Among the acute effects of cigarette smoking there are an increase in the arterial blood pressure and a decrease in skin temperature. The aim of this study is to evaluate whether these effects are more evident in hypertensive subjects (HTS) than in normotensive (NTS) ones. METHODS: A monitored Ambulatory Blood Pressure method, an Agema 880 Thermograph and a Surgitron thermal stimulator have been employed. Ten NTS males and 10 HTS, age paired (50-60 years, mean 57.8), were examined. Area of interest, the volar face of the fingertips. The pressural and thermographic tests were performed with patients staying in a proper room for 2 h, smoking consecutively 4 cigarettes, one every 14 min. The tests were made at 0 time (baseline), after smoking each cigarette and, finally, 60' after the beginning of the last one. RESULTS: A rise in blood pressure and a fall in skin thermal gradients both in HTS and in NTS was seen since the first cigarette, and these values, more evidently in hypertensive subjects, were appeared progressively increased along with the other 3 cigarettes. CONCLUSIONS: These results confirm the damage of smoking on peripheral blood vessels verified and also the cumulative effect of smoking more cigarettes. The similar increased percentage of ABP and telethermography (TT) values in these tests lead us to consider TT as a routinary method for the evaluation of a more general vascular damage provoked by cigarette smoking. Also, the immediate visual thermal effect (=thermal amputation) after smoking is very useful in smoking educative programs.

Blood Pressure↗