bluuebunny/crossref_metadata_2025_split huggingface dataset:
EFFECT OF ACETYLCHOLINE AND MORPHINE ON BRONCHIAL SMOOTH MUSCLE CONTRACTION AND ITS MODULATION BY STEROID HORMONES
Authors: Nabishah B. M. , Morat P. B. , Khalid B. A. K. , Kadir B. A. 
Published: June 2007

SUMMARY1. The effects of corticosteroid pretreatment on acetylcholine (ACH)‐induced contraction of bronchial smooth muscle (BSM) were studied.2. ACH dose‐response curves for dexamethasone (DM)‐ and corticosterone (B)‐treated but not deoxycorticosterone (DOC)‐treated BSM were significantly shifted to the right; this provides evidence that glucocorticoid treatment reduced the sensitivity of BSM to ACH.3. Morphine enhanced BSM contraction in response to ACH by 20%. DM suppressed this enhancement.4. These findings correlated well with the reduction of muscarinic receptor numbers in BSM by glucocorticoids in our previous study. In addition, glucocorticoids reduced the sensitivity of BSM to opioids.
COMPARISON OF THEOPHYLLINE AND ENPROFYLLINE EFFECTS ON HUMAN NEUTROPHIL SUPEROXIDE PRODUCTION
Authors: Kaneko Michie , Suzuki Kenji , Furui Hidehiko , Takagi Kenzo , Satake Tatsuo 
Published: June 2007

SUMMARY1. We investigated effects of theophylline (widely used for the treatment of asthma) and enprofylline (a new xanthine derivative with negligible adenosine antagonism) on O2‐ production by human neutrophils with n‐formyl‐methionylleucyl‐phenylalanine (FMLP) stimulation.2. Therapeutic concentrations of theophylline (1–100 μmol/L) enhanced O2‐ production, maximally by 43.1 ± 24.4% at 30 μmol/L; the same concentrations of enprofylline inhibited O2‐ production.3. When each agent was administered after pre‐incubation with adenosine deaminase (ADA) (0.1 U/mL), O2‐ production was inhibited in a concentration‐dependent manner in comparison with that under administration of ADA alone.4. These results suggest that the difference of effects in the two xanthine derivatives at therapeutic concentrations might be due to the presence or absence of adenosine antagonism.
EFFECTS OF STROPHANTHIDIN ON THE SLOW INWARD CURRENT IN GUINEA‐PIG ISOLATED VENTRICULAR MYOCYTES
Authors: Yang Lie , Vassalle Mario 
Published: June 2007

SUMMARY1. The effect of strophanthidin on the slow inward current (Isi) and on contractile force were studied in guinea‐pig isolated ventricular myocytes and intact papillary muscles, respectively. In myocytes, both low (10 nmol/L) and high (1–10 μmol/L) concentrations had small or no effects in either direction on Isi whereas norepinephrine (10–100 nmol/L) increased it. To determine whether the same results are obtained after decreasing or increasing intracellular calcium or sodium, the same concentrations of strophanthidin were tested in different procedures that are known to (i) increase [Ca]i and decrease [Na]i (high [Ca]o, 3.6–5.4 mmol/L; low [Na]o, 112 mmol/L; (ii) decrease [Ca]i and increase [Na]i (low [Ca]o, 0.45–1 mmol/L; Sr, 1 mmol/L; (iii) decrease [Ca]i and [Na]i (Cd, 0.1–0.2 mmol/L); and (iv) increase [Ca]i and [Na]i (veratridine, 0.2 μmol/L). High [Ca]o and veratridine increased whereas low [Ca]o and Cd decreased Isi. In contrast, during these various procedures, strophanthidin had small and inconsistent effects at a low or high concentration. In intact papillary muscles, low strophanthidin decreased whereas high strophanthidin increased contractile force. It is concluded that strophanthidin has little direct or indirect effect on Isi and that the decrease in force by low and increase in force by high concentrations in intact muscle are probably related to demonstrated decrease and increase, respectively, in intracellular sodium activity.
A RENIN‐SECRETING TUMOUR SENSITIVE TO CHANGES IN CENTRAL BLOOD VOLUME (PRESUMABLY VIA SYMPATHETICS) BUT NOT TO CIRCULATING ANGIOTENSIN II
Authors: Gordon Richard D. , Tunny Terry J. , Klemm Shelley A. , Finn Wendy L. , Hawkins Peter J. , Hunyor Stephen J. , Norris John J. 
Published: June 2007

SUMMARY1. A 17 year old female presented with severe hypertension, hypokalaemia and elevated levels of plasma renin activity due to a renin‐secreting tumour.2. Renin was responsive to posture, low sodium diet, saline infusion and frusemide, but relatively unresponsive to raising or lowering circulating levels of angiotensin II.3. Renal venous renin levels lateralized to the side of the tumour with good contralateral suppression when measured with control of posture and avoidance of prior stimulation, with and without angiotensin converting enzyme inhibition.4. Levels of atrial natriuretic peptide were elevated and responsive to posture, saline infusion and angiotensin infusion.5. The tumour was evident on computerized tomography, but not on intravenous pyelography or renal angiography.6. Responsiveness of renin secretion to normal stimuli in reninoma may make diagnosis difficult, and renal vein sampling under controlled conditions is necessary.
A FACTORIAL STUDY OF FAT AND FIBRE CHANGES AND SODIUM RESTRICTION ON BLOOD PRESSURE OF HUMAN HYPERTENSIVE SUBJECTS
Authors: Sciarrone S. E. G. , Rouse I. L. , Rogers P. , Beilin L. J. 
Published: June 2007

SUMMARY1. Diets used to reduce sodium intake often involve changes in fats and fibre which might themselves affect blood pressure and/or lipid metabolism. To evaluate the relative importance of these dietary changes for the management of hypertension we have studied the independent and additive effects of sodium restriction (60 mmol/day) and a low fat (30% energy), high P/S ratio (1.0), high fibre (30–50 g/day) ‘cholesterol lowering’ diet.2. Ninety‐five hypertensives entered a four group parallel study with a factorial design. Following 5 weeks familiarization subjects [BP range 109/66–168/105 mmHg] were randomly assigned to either a ‘low sodium, cholesterol lowering’ diet or a ‘low sodium, cholesterol maintaining’ diet. Half the subjects in each group were then assigned to 100 mmol/day NaCl supplement and the remainder to placebo. These diets were continued for 8 weeks. Seventy‐nine of the 91 hypertensives who completed the study were on antihypertensive therapy throughout.3. Mean urinary sodium excretion decreased from 137 (54 mmol/day (n= 43) at baseline (B) to 52 (32) mmol/day (n= 45, P= 0.0001) during intervention (I) in the low sodium groups and remained unchanged in the groups which received slow sodium (B = 129 [46], n= 43; I = 134 [29], n= 42). Diet record and plasma fatty acid analysis confirmed that the dietary aims of the study were achieved.4. Sodium restriction reduced supine and standing systolic BP by a mean (± s.e.m.) of 6±2 and 6±4 mmHg, respectively (P<0.005). The low fat/high fibre diet had no independent or additive effect on blood pressure reduction but reduced total and LDL cholesterol by an average of 0.74 and 0.59 mmol/L, respectively (P<0.0001).5. In terms of reducing overall risk of cardiovascular disease, diets which combine sodium restriction with measures to reduce LDL cholesterol would appear optimal.
ISOLATED SYSTOLIC HYPERTENSION: DOES IT REALLY EXIST ON AMBULATORY BLOOD PRESSURE MONITORING?
Authors: Silagy C. A. , McNeil J. J. , McGrath B. P. 
Published: June 2007

SUMMARY1. The diagnosis of isolated systolic hypertension, diastolic hypertension and normotension in elderly subjects, as defined by casual office blood pressure measurement, was compared with 24 h ambulatory blood pressure monitoring using an Accutracker II.2. Mean day‐time ambulatory blood pressure monitoring underestimated the casual systolic blood pressure in all three clinical groups. Diastolic pressure was not underestimated to the same extent.3. Ambulatory blood pressure monitoring best reflected casual blood pressure determination for normotensive subjects. In subjects with isolated systolic hypertension ambulatory blood pressures were only consistent with that diagnosis for 8% of the day time period. For 34% of the day time, their ambulatory blood pressures were consistent with diastolic/ mixed hypertension.4. It is concluded that isolated systolic hypertension may not be a sustained condition, but rather an isolated response to office measurement of blood pressure.
PREVALENCE OF LEFT VENTRICULAR HYPERTROPHY IN ELDERLY PATIENTS WITH WELL CONTROLLED HYPERTENSION
Authors: Jones Elizabeth , Morgan Trefor O. , Califiore Paul , Johns Jennifer 
Published: June 2007

SUMMARY1. Left ventricular hypertrophy (LVH) was measured by echocardiography in 154 patients, mostly males, aged 55 years or more, with hypertension who had been well controlled for at least 2 years.2. Satisfactory studies with no other cardiac lesions were available for 103 patients; 52% had LVH and 48% had normal left ventricular dimensions.3. In patients with well controlled hypertension there was a high prevalence of LVH despite adequate control for at least 2 years. Neither the level of control nor the drugs used appeared to predict the outcome.4. Consideration needs to be given to earlier treatment, greater lowering of blood pressure, or different drugs to reduce this high prevalence of LVH.
EFFECTS OF REGULAR ALCOHOL CONSUMPTION ON 24 HOUR AMBULATORY BLOOD PRESSURE RECORDINGS
Authors: Howes L. G. , Krum H. , Phillips P. A. 
Published: June 2007

SUMMARY1. Regular consumption of 1 g/kg of alcohol for 4 days did not significantly alter mean 24 h blood pressures compared with a similar period when dextrose was consumed to match caloric intake.2. In contrast, the variability of diastolic blood pressure was increased by regular alcohol consumption.3. Increased blood pressure variability in response to the stress of blood pressure measurement may contribute to the observed association between hypertension and alcohol consumption.
EFFECT OF GRADED ADRENALINE INFUSION ON ARTERIAL ADRENALINE CLEARANCE IN NORMOTENSIVE AND HYPERTENSIVE MAN
Authors: Bachmann Anthony W. , Gordon Richard D. , Bathgate Ross A.D. , Thompson Robyn E. 
Published: June 2007

sUMMARY1. Arterial adrenaline (ADR) levels were measured during graded ADR infusions in normotensives (NT) and in mild hypertensives (HT), in order to test the hypothesis that ADR enhances its own clearance in NT.2. Although infusion of ADR resulted in similar arterial ADR levels in NT and HT, increases in systolic blood pressure (SBP) and heart rate (HR) and decreases in diastolic blood pressure (DBP) were greater during ADR infusion in HT than in NT.3. Twenty minutes after cessation of infusion, SBP and HR remained elevated in HT but not in NT.4. No evidence was found supporting enhanced ADR clearance during increasing ADR levels in NT or HT.
INHIBITION OF ENDOTHELIAL NITRIC OXIDE BIOSYNTHESIS BY N‐NITRO‐l‐ARGININE
Authors: Dubbin Philip N. , Zambetis Maria , Dusting Gregory J. 
Published: June 2007

SUMMARY1. The actions of N‐nitro‐L‐arginine (NOLA) on the release of nitric oxide (NO) from arterial endothelial cells was studied in rat isolated thoracic aortic rings and by bioassay of NO derived from cultured bovine aortic endothelial cells.2. NOLA (3–10 μmol/L) caused concentration‐dependent inhibition of acetyl‐choline‐induced relaxation of phenylephrine‐contracted rat aortic rings, which is dependent on the release of NO from the endothelium. The inhibitory actions of NOLA could be prevented by pre‐ and co‐incubation with L‐arginine (1 mmol/L).3. Endothelium‐independent relaxation induced by sodium nitroprusside was not affected by NOLA.4. The release of NO from bovine aortic endothelial cells, induced by bradykinin (10 nmol/L), was detected by bioassay on pre‐contracted rabbit aortic strips. NOLA (1–3 μmol/L, given through the cell column) reduced or abolished the release of NO, but did not affect relaxations of the bioassay tissues induced by glyceryl trinitrate or authentic NO.5. These data indicate that NOLA potently inhibits the biosynthesis of NO from L‐arginine, and thus prevents its release from arterial endothelial cells. It may be a useful pharmacological tool for probing the significance of NO biosynthesis in cardiovascular function.
SODIUM‐DEPENDENT, ETHYLISOPROPYLAMILORIDE‐SENSITIVE MECHANISMS REGULATE INTRACELLULAR pH IN HUMAN VASCULAR SMOOTH MUSCLE
Authors: Bobik Alex , Neylon Craig B. , Little Peter J. , Jr Edward J. Cragoe , Weissberg Peter L. 
Published: June 2007

SUMMARY1. The pH‐sensitive dye 2,7‐biscarboxy‐ethyl‐5(6)‐carboxyfluorescein (BCECF) was used to examine the contribution of Na+‐H+ exchange and bicarbonate‐dependent processes to intracellular pH (pHi) regulation in cultured human vascular smooth muscle.2. The recovery of pHi following an NH4Cl‐induced acidosis was Na+‐dependent and could be inhibited by ethylisopropylamiloride (200 μmol/L). Recovery was unaffected by the anion exchange inhibitor 4‐acetamido‐4′‐isothio‐cyano‐stilbene‐2,2′‐disulfonic acid (200 μmol/L).3. Recovery from intracellular acidosis was more rapid when bicarbonate ions were present in the extracellular medium.4. The results suggest that Na+‐H+ exchange as well as an Na+‐dependent bicarbonate process, which can be inhibited by ethylisopropylamiloride, can influence the ability of smooth muscle to recover from intracellular acidosis.
SHIFT IN THE BAROREFLEX‐RENAL NORADRENALINE SPILLOVER CURVE DURING THE DEVELOPMENT OF CONGESTIVE HEART FAILURE IN THE RABBIT
Authors: McGrath Barry P. , Sano Naoki , Way Diana 
Published: June 2007

SUMMARY1. Changes in renal sympathetic nerve activity (RSNA) were investigated during the development of congestive heart failure (CHF) in rabbits with doxorubicin‐induced cardiomyopathy.2. Controls (saline treated, n= 5) and doxorubicin‐treated rabbits (1 mg/kg administered intravenously twice weekly, n= 5) were studied after 4 and 6 weeks treatment.3. RSNA was estimated by measuring renal noradrenaline spillover rate under resting conditions and in response to changes in arterial pressure induced by phenylephrine and sodium nitroprusside infusions.4. In the doxorubicin‐treated group, resting renal noradrenaline spillover was increased at 4 weeks (24.2 ng/min, s.e.m. = 2.5, n= 5) compared with controls (15.2 ng/min, s.e.m. = 2.4, n= 5; P<0.01) and remained elevated.5. The baroreceptor–renal noradrenaline spillover curve showed a significant upward shift in the doxorubicin‐treated group at 4 weeks. After 6 weeks both heart rate and renal noradrenaline spillover responses to hypotension were significantly blunted.6. It is suggested that increased RSNA occurs early during the development of CHF in doxorubicin‐treated rabbits. The observed changes in the baroreflex responses suggest that different mechanisms may contribute to this increased RSNA at different stages of CHF.
EFFECTS ON SHEEP BLOOD PRESSURE OF TREATMENT WITH ANGIOTENSIN, STEROIDS AND SALT
Authors: Lumbers Eugenie R. 
Published: June 2007

SUMMARY1. Angiotensin II (AII, 0.22 μg/min) infused for 7–14 days, into adult unanaesthetized wethers, caused a rise in blood pressure of 7±3/7±3 mmHg (mean ± s.e.m.) from control values of 90±5/54±3 mmHg (P<0.05, n= 11). Cardiac output and pulse interval were not affected. A high salt intake had no effect on blood pressure, cardiac output and pulse interval, nor did it potentiate the action of AII.2. Ethinyl oestradiol (EE, 20 mg/week) caused a small fall in systolic and diastolic pressure of 6±3/6±5 mmHg (n= 7, P<0.1, P<0.05). When AII (0.22 μg/min) was given with EE, it still caused a significant rise in blood pressure (P<0.01). The synthetic progestin (1 mg of norethisterone [NE] for 8–18 days) plus a high salt diet had no effect on arterial pressure and cardiac output but pulse interval rose significantly (P<0.05).3. Therefore the reduction in vascular reactivity to angiotensin seen in human pregnancy is probably not related to high levels of oestrogen. Further, NE combined with a high salt diet does not cause hypertension in sheep.
METABOLISM OF TETRADECAPEPTIDE, ANGIOTENSINOGEN AND ANGIOTENSIN I AND II BY ISOLATED PERFUSED RAT HINDLIMBS
Authors: Campbell Duncan J. , Ziogas James , Kladis Athena 
Published: June 2007

SUMMARY1. We investigated the mechanism of tetradecapeptide‐induced vasoconstriction by studying the metabolism of tetradecapeptide (TDP), angiotensinogen, and angiotensin I (AI) and angiotensin II (AII) by isolated perfused rat hindlimbs.2. Using HPLC and specific RIAs we have quantified six angiotensin peptides: pentapeptide(4–8), hexapeptide(3–8), heptapeptide(2–8), octapeptide(1–8), nonapeptide(2–10) and decapeptide(1–10) in hindlimb effluent.3. TDP‐induced vasoconstriction was associated with generation of predominantly AI and AII, with smaller amounts of the other peptides measured.4. Captopril prevented vasoconstriction and inhibited AII production by 80%, indicating a dominant role for AI generation in the vascular response to TDP.5. Evidence that renin is not the enzyme responsible for AI generation from TDP includes: first, the failure of angiotensinogen to cause vasoconstriction or angiotensin peptide generation despite very high amounts of AI and AII generation from TDP; second, the resistance of the TDP‐induced vasoconstriction and angiotensin peptide generation to inhibition by pepstatin; and third, the failure of bilateral nephrectomy 24 h before the experiment to influence the vascular and angiotensin peptide response to TDP.6. AII was cleared with 41% efficiency, with generation of penta‐, hexa‐, and heptapeptides.7. AI was cleared with 59% efficiency; this was reduced to 24% by captopril, indicating a conversion of at least 35% of AI to AII by ACE.8. These studies have identified vascular metabolism of AI and AII to be an efficient process, with both ACE and aminopeptidases playing an important role, and indicate that those peptidases which cleave TDP to generate AI are unlikely to play any role in AI generation in vivo.
INFLUENCE OF NEONATAL HYPOTHYROIDISM ON ADRENAL TYROSINE HYDROXYLASE ACTIVATION IN THE YOUNG RAT
Authors: Valens M. , Gripois D. 
Published: June 2007

SUMMARY1. Adrenal TH activation was elicited in young rats (aged 4,6 and 14 days) by insulin hypoglycaemia. In the control rats, TH activation varied between 125 and 147% above basal values.2. Neonatal hypothyroidism induced by PTU treatment impaired TH activation. Compensatory treatment with T3 to the PTU‐treated young rats led to a return to control activation.
ANTIDIURETIC EFFECTS OF NEUROTENSIN IN CHLORALOSE ANAESTHETIZED DOGS
Authors: Kivlighn Salah D. , Jandhyala Bhagavan S. 
Published: June 2007

ABSTRACT1. Effects of cerebroventricular and/or intravenous infusions of neurotensin (NT), an endogenous tridecapeptide, on haemodynamics and renal function were investigated in chloralose anaesthetized dogs.2. Cerebroventricular infusions (i.c.v.) of NT (10‐6 mol/L and 10‐5 mol/L, 0.1 mL/min) for 30 min did not produce any significant alterations in the measured variables. In the vagotomized dogs, intravenous (i.v.) infusion of NT (10‐5 mol/L) at a rate of 0.1 mL/min for 30 min significantly lowered the arterial blood pressure and glomerular filtration rate; these effects were accompanied by pronounced reductions in the urine flow and urinary sodium excretion and marked increases in urine osmolality.3. In the dogs with vagi intact, i.v. infusions of NT failed to produce any alterations in the blood pressure; however, renal effects of NT were essentially identical to those observed in the vagotomized dogs.4. Infusions of NT (10‐6 mol/L) and/or NT‐metabolites NT1‐8 and NT8‐13 (10‐5 mol/L) directly into the renal artery failed to produce any significant alterations in the urine flow. Antidiuretic effects of i.v. NT were not prevented by acute renal denervation, adrenalectomy, or pretreatment of the animals with naloxone. However, morphine pretreatment completely abolished the hypotensive and antidiuretic effects of NT.5. It is proposed that i.v. infusion of NT rapidly facilitates the secretion of an endogenous substance possessing potent antidiuretic properties and opiate mechanisms are involved in mediating such an effect. Although it appears unlikely, a role for vasopressin cannot be ruled out.
CALCITONIN GENE RELATED PEPTIDE: VASODILATOR IN OVINE HEPATIC AND RENAL VASCULATURE
Authors: Fletcher David R. , Braslis Karl G. , Shulkes Arthur , Hardy Kenneth J. 
Published: June 2007

SUMMARY1. Calcitonin gene‐related peptide (CGRP) is a product of alternate splicing of the calcitonin gene. It is found in nerves in the vasculature and is known from in vitro studies to be a potent vasodilator. It is found abnormally in the circulation of patients with medullary thyroid carcinoma (MTC) and has been proposed to be a cause of symptoms. This study was designed to determine the dose‐response effects of CGRP infusion in the intact conscious sheep on blood flow to liver and kidney, organs known to be richly innervated by CGRP‐containing nerves.2. Blood flow was measured by an indicator dilution technique using [131I]‐labelled iodohippurate. CGRP infusion at both 1 and 5 pmol/kg per min produced significant (P<0.05) increases in both renal and hepatic blood flow. This increase in flow occurred despite a significant fall in perfusion pressure (P<0.05) at the higher infusion rate. At the highest infusion rate of 10 pmol/kg per min, when fall in perfusion pressure was even more marked, renal and hepatic blood flow was maintained.3. We conclude that CGRP is vasodilatory in the renal and hepatic vascular beds and propose that nerves containing CGRP in those vessels may have a role in maintaining blood flow to those organs.
TIME COURSE OF RECOVERY OF β‐ AND α1‐ADRENOCEPTORS IN EXPERIMENTAL ASTHMA
Authors: Shindoh Joe , Sugiyama Satoru , Hayashi Kouichi , Takagi Kenzo , Satake Tatsuo , Ozawa Takayuki 
Published: June 2007

SUMMARY1. The time course of recovery of reduced β‐adrenoceptors caused by ovalbumin (OA) challenge was investigated using guinea‐pigs.2. The effects of prednisolone on the recovery time course were also evaluated.3. β‐ and α1‐receptor assays were performed using lung membranes. Adenylate cyclase activity was also measured.4. OA challenge reduced the number of β‐adrenoceptors by 35%, and a significant decrease (13%) persisted for 7 days. The number of β‐adrenoceptors recovered after 14 days.5. OA challenge elevated the number of α1‐adrenoceptors. A significant increase (24%) was observed after 7 days, and it took a further 7 days for the recovery.6. After OA challenge there was a significant decrease in adenylate cyclase activity after 7 days, which recovered after a further 7 days.7. Inhalation of prednisolone accelerated the recovery of β‐adrenergic responsiveness, though it did not affect the recovery of the number of α1‐adrenoceptors. Prednisolone inhalation also elevated β‐adrenergic responsiveness in non‐asthmatic subjects.8. It is concluded that reduced β‐adrenergic responsiveness caused by OA challenge persisted for 7 days and recovered after a further 7 days. Steroid hormone increased β‐adrenoceptors.
THE ANTINOCICEPTIVE ACTIONS OF KAVA COMPONENTS IN MICE
Authors: Jamieson D. D. , Duffield P. H. 
Published: June 2007

SUMMARY1. The antinociceptive properties of the aqueous extract of the intoxicating beverage kava, and of the lipid soluble extract (kava resin) were tested in mice, by the tail immersion and abdominal constriction methods. Both extracts showed analgesic effects in both tests.2. Eight purified pyrones from the lipid soluble extract were also tested for activity in the tail immersion test, and kawain, dihydrokawain, methysticin and dihydromethysticin were found to be very effective in producing analgesia. Using the tail immersion test the time course of action of the extracts of the four effective pyrones of kava were studied.3. Naloxone, in doses which inhibited morphine‐induced analgesia in both tests, was completely ineffective in reversing the antinociceptive activities of the kava extracts, showing that analgesia produced by kava occurs via non‐opiate pathways.