bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effects of acute and long‐term atropine treatment on levels, release and response to VIP and PHI in the submandibular gland of cat and rat
Authors: DUNÉR‐ENGSTRÖM M. , LARSSON O. , FREDHOLM B. B. , LUNDBLAD L. , FAHRENKRUG J. , LUNDBERG J. M. 
Published: December 2008

We have studied the effects of acute and long‐term treatment of cats and rats with atropine on the levels, release and effects of two peptides, vasoactive intestinal polypeptide (VIP) and peptide histidine isoleucine (PHI), that probably co‐exist with acetylcholine in the parasympathetic nerves supplying the submandibular gland.Atropine treatment (progressively increasing doses from 2 to 15 mg kg‐1 injected s.c.) for 14 days did not alter the contents of VIP‐ or PHI‐like immunoreactivity (‐IR) in the cat submandibular gland or in three other tissues (nasal mucosa, trachea and tongue). Acute as well as long‐term atropine treatment decreased the vasodilatation following low‐, but not high‐, frequency parasympathetic nerve stimulation. During prolonged stimulation (60 min) there was a decreased vasodilatation response following both acute and long‐term atropine treatment. The overflow of VIP‐IR and PHI‐IR following parasympathetic nerve stimulation was markedly increased by acute, but not by long‐term atropine treatment. The VIP‐ or PHI‐induced stimulation of cyclic AMP (cAMP) accumulation in the cat submandibular gland was not altered after long‐term atropine treatment.Similarly, treatment of male Sprague‐Dawley rats with atropine (20 mg kg‐1) or imipramine (20 mg kg‐1) for 14 days did not alter the sensitivity to VIP or to PHI of cAMP accumulation in the submandibular gland, nor was there any change in VIP‐IR or PHI‐IR content.In conclusion, although atropine treatment causes an acute increase in the overflow of VIP and PHI evoked by parasympathetic nerve stimulation, there is no depletion of peptide stores upon long‐term treatment, nor is there any change in the effect of exogenous VIP and PHI on cAMP‐accumulation.
Non‐linearity of skin resistance response to intraneural electrical stimulation of sudomotor nerves
Authors: KUNIMOTO M. , KIRNÖ K. , ELAM M. , KARLSSON T. , WALLIN B. G. 
Published: December 2008

Intraneural electrical stimuli (0.3 mA, 0.2 ms) were delivered via a tungsten micro‐electrode inserted into a cutaneous fascicle in the median nerve at the wrist in 16 normal subjects, and the effects on the sweat glands within the innervation zone were recorded as changes of skin resistance. In order to examine the relationship between the skin resistance level and the amplitude of transient resistance responses, trains of high frequency stimulation were used to reduce the skin resistance level and then transient resistance responses were evoked by single stimuli at 0.1 Hz. Regional anaesthesia of the brachial plexus in the axilla eliminated spontaneous sympathetic activity and reflex effects.At high skin resistance levels response amplitudes to single stimuli were low but they increased successively to a maximum at intermediate levels and then decreased again at low resistance levels. Repeated stimulation sequences evoked qualitatively similar response curves but quantitatively both response amplitudes and skin resistance levels were slightly reduced upon repetition.We suggest that the changes of response amplitudes are due to variable resistivity of the corneal layer. The shifts of the response curves with repetition of stimulation may result from increased hydration of the corneum.It is concluded that the variability of response amplitudes to constant stimuli makes the amplitude of a skin resistance response unsuitable as an indicator of the strength of sympathetic sudomotor nerve traffic.
Tolerance to haemorrhage during vasopressin antagonism and/or captopril treatment in conscious sheep
Authors: ULLMAN J. E. , HJELMQVIST H. , LUNDBERG J. M. , RUNDGREN M. 
Published: December 2008

The effect of separate and combined blockade of vasopressin (AVP) V1‐receptors and angiotensin II formation on resistance to a slow venous haemorrhage (0.7 ml kg‐1 min‐1) was studied in six conscious adult sheep by bleeding to the point of an abrupt fall in the mean systemic arterial pressure (MSAP). Intravenous administration of the V1‐receptor antagonist [d(CH2)5Tyr(Me)AVP] (10 μg kg‐1) and/or the angiotensin I converting enzyme inhibitor captopril (20 mg+1 mg h‐1) did not cause any significant haemodynamic changes in the normovolaemic animal. The volume of haemorrhage necessary to induce acute hypotension (MSAP < 50 mmHg) was significantly smaller after AVP blockade alone (13.8±0.7 ml kg‐1; P < 0.01) but not after captopril treatment (14.7±1.6 ml kg‐1; n.s.) compared to control animals receiving no drug treatment (16.8±0.6 ml kg‐1). The combined treatment with the AVP antagonist and captopril caused a further decrease in tolerance to haemorrhage (9.4±1.2 ml kg‐1; P < 0.001).Blockade of AVP V1‐receptors was associated with an attenuated increase in systemic vascular resistance immediately after the end of haemorrhage, concomitant with an accentuated lowering of the central venous pressure. In contrast, captopril treatment decreased the degree of vasoconstriction mainly during the second half of the post‐haemorrhage observation period of 1 hour.It is concluded that both AVP and angiotensin II contribute to the maintenance of the MSAP during haemorrhage in conscious sheep. During the spontaneous recovery after hypotensive blood loss, a vasoconstrictor effect of AVP is evident mainly during the initial 15 min, whereas at later stages angiotensin II appears to be of relatively greater importance.
The mediation of increased duodenal alkaline secretion in response to 10 mm HCI in the anaesthetized rat. Support for the involvement of capsaicin‐sensitive nerve elements
Authors: HAMLET A. , JÖNSON C. , FÄNDRIKS L. 
Published: December 2008

Experiments were performed on chloralose‐anaesthetized rats. Bicarbonate secretion by the duodenal mucosa was continuously recorded by use of an in situ‐titration technique. Exposing the duodenal segment to 10 mM HCl over 5 min increased the bicarbonate transport by about 65%. This acid‐induced secretory response was resistant to neural decentralization by means of bilateral cervical vagotomy and/or splanchnicotomy. Furthermore, in the decentralized state, serosal application of the local anaesthetic lidocaine or tetrodotoxin (TTX) lowered basal duodenal bicarbonate secretion. Despite the presence of lidocaine or TTX, exposure of the duodenal mucosa to 10 mM HCl induced a net increase in secretion with a magnitude similar to that observed in the control situation with intact nerves. A 5‐min exposure period of the decentralized duodenal segment to capsaicin (1.2 mg ml‐1) raised bicarbonate secretion, a response which also occurred in the presence of lidocaine (serosa). Tachyphylaxis to capsaicin blocked the secretory response to 10 mM HCl and inhibited the response to luminal prostaglandin E2 (1.5 10‐5 M) by 80%.The present results indicate that luminal exposure to 10 mM HCl activates capsaicinsensitive primary afferents which, locally within the submucosa or epithelium, activate the bicarbonate secretion.
Neuropeptide Y and differential sympathetic control of splenic blood flow and capacitance function in the pig and dog
Authors: MODIN A. , PERNOW J. , LUNDRERG J. M. 
Published: December 2008

The roles of different mediators in the sympathetic regulation of the pig and dog spleens were investigated using a preparation with intact vascular perfusionin vivo. Sympathetic nerve stimulation caused overflow of neuropeptide Y‐like immunoreactivity (NPY‐LI) and noradrenaline (NA), arterial vasoconstriction, increase in venous blood flow and haematocrit. The dog spleen responded to single impulse stimulation, whereas more prolonged stimulation was required to elicit vascular responses in the pig spleen. Furthermore, the maximal splenic capacitance response was about 10 times larger in the dog than in the pig. After depletion of neuronal NA content by reserpine combined with preganglionic denervation, about 70% of the splenic arterial vasoconstrictor responses in the dog and pig still remained at 5 Hz stimulation. Fifty per cent of the capacitance response evoked by nerve stimulation still remained in the pig while in the dog spleen the capacitance response was virtually abolished after reserpine. The stimulation‐evoked overflow of NPY‐LI in pig spleen was increased several fold after reserpine treatment as compared to controls reaching levels in the venous effluent where exogenous NPY evokes vasoconstriction. In the dog spleen, overflow of NPY‐LI was only observed after reserpine. Administration of NA caused arterial vasoconstriction with an initial increase in venous blood flow while NPY mainly reduced arterial blood flow.It is concluded that NA is involved in both the splenic arterial vasoconstriction and the capacitance responses while a non‐adrenergic splenic vasoconstriction at least in the pig may be mediated by NPY.
Increased pressure in venous sinusoids during decongestion of rat nasal rnucosa induced by adrenergic agonists
Authors: KRISTIANSEN A. B. , HEYERAAS K. J. , KIRKEBB A. 
Published: December 2008

The haemodynamic effects of sympathetic agonists causing decongestion of the nasal mucosa have been investigated in rats. Access to mucosa was obtained from the dorsal side through a small cavity drilled in the nasal bone. The pressures in the venous sinusoids and in the interstitial fluid of nasal mucosa were recorded by micropuncture technique. The local red cell flux (LDF) was monitored by laser Doppler flowmetry, and the blood volume in the mucosa was measured by radio‐labelled erythrocytes and albumin.In control rats the tissue blood volume was 0.25 ± 0.03 g (g wet wt)‐1. The interstitial fluid pressure (IFP) was 2.4± 0.6 mmHg and the average blood pressure in venous sinusoids (Ps) was 12.8 ± 2.7 mmHg.After topical application of noradrenaline (NA) the local blood volume was reduced to 0.12 ± 0.03 g g‐l. P, was increased to 18.0 ± 4.0 mmHg, whereas IFP was maintained and LDF was reduced to 40.4% of control, indicating a greater rise in post than in presinusoid vascular resistance.Blocking of both α1, and α2,‐receptors by phentolamine caused a rise in mucosa blood volume and in LDF by 16 and 20% of control, respectively. Ps, increased significantly to 15.2 ±3.3 mmHg.Specific stimulation or blocking of α1,‐receptors by phenylephrine or prazosin induced similar or slightly smaller vascular responses than NA or phentolamine. The effects of the specific α2‐agonist (clonidine) or antagonist (yohimbine) on rat mucosa were small, indicating a domination of the α1,‐receptors.Thus, application of NA caused a rise in blood pressure in the venous sinusoids of nasal mucosa. As LDF fell simultaneously, the reduced blood volume must be due to an increased tone in the muscular wall of venous sinusoids.
A search for arteriovenous anastomoses in human skin using ultrasound Doppler
Authors: BERGERSEN T. K. 
Published: December 2008

The possible existence of arteriovenous anastomoses (AVAs) in skin regions of the head and thorax has been investigated using the synchronous vasomotion of the AVAs. Simultaneous pairs of blood velocity recordings were made using pulsed, bidirectional Doppler ultrasound. In each pair of registrations, blood velocity was recorded in a reference artery supplying a skin area known to contain AVAs (the radial artery) together with one of four other arteries investigated, i.e. the facial artery, the angular artery, the temporal artery, and the cutaneous branches of the lateral thoracic artery.The typical large, regular fluctuations in blood velocities caused by synchronous vasomotion in the AVAs in the skin of the hand and fingers were observed invariably in the radial artery. Similar flow variations were found in the angular artery. The fluctuations in this and the radial artery were, in turn, found to be synchronous. However, we have not been able to find the flow patLern characteristic of AVA vasomotion in the temporal artery or in the cutaneous branches of the lateral thoracic artery.These results show that the skin area of the nose supplied by the angular artery contains AVAs. These AVAs partly may explain the important role of face skin in temperature regulation. These results also support the earlier assumptions that there are no or very few AVAs in the skin areas supplied by the temporal artery and the cutaneous branches of the lateral thoracic artery.
Plasma potassium concentration and Doppler blood flow during and following submaximal handgrip contractions
Authors: JENSEN B. R. , FALLENTIN N. , BYSTRÖM S. , SJØGAARD G. 
Published: December 2008

The aim of the present study was to investigate the time‐course of blood velocity in the forearm during and folllowing isometric handgrip contractions and to reveal a possible temporal relationship between the circulatory response and venous effluent potassium concentration ([K]) not only during contractions but also during the post‐exercise recovery period. Contractions of 15% maximal voluntary contraction (MVC) and 30% MVC with and without 3 min of artirial occlusion following the contractions were studied.All contractions induced a significant increase in venous plasma [K] from an average resting level of 4.0 to 5.0 mM during 15% MVC and 5.8 mM during 30% MVC. Blood velocity increased from a resting level of 0.07 to 0.22 m s‐1 diromg 15% and 30% MVC, respectively. MCC of 30% always elicited a larger blood velocity and [K] response than 15% MVC.Following the contractions hyperaemia was elicited. Recovery of the local blood velocity was markedly slower than the K recovery, since [K] remained significantly above resting level for only 25 s following 15% MVC and 45 s following 15 and 30% MVC, respectively. Further, a larger hyperaemia following the occlusion was elicited as compared to the contraction without occlusion, in spite of [K] being lower immediately after the occlusion period than immediately after the contraction. Finally, [K] decreased below resting level in the recovery period while the blood velocity remained elebvated. Therefore, the present study showed that the venous plasma [K] is not causally related to the prolonged post‐exercise hyperaemia.The skin temperature remained unchanged during the contractions, while during the recovery period the skin temperature increased for several minutes. The major part of the temperature increase was likely to be due to conductance of heat from muscles to skin surface as a consequence of muscle hyperaemia.
Differential projection of the sural nerve to early and late recruited human tibialis anterior motor units: change of recruitment gain
Authors: NIELSEN J. , KAGAMIHARA Y. 
Published: December 2008

The effect of a stimulation of the cutaneous sural nerve [three shocks, 2.5 × perception threshold (PT)] was studied on the tibialis anterior (TA) H‐reflex and single voluntarily activated TA motor units using post‐stimulus time histograms (PSTH). In both cases, when studying only the first recruited motor units, an inhibition with a delay of 10 ms, in relation to the monosynaptic latency of Ia afferents in the common peroneal nerve, was observed. This inhibition had a duration of 10–20 ms.The inhibition was evoked by low‐threshold cutaneous fibres, since it could be seen at a stimulation strength close to the perception threshold. The central delay of the inhibition was calculated in two subjects to be 1.8 ms and 1.2 ms respectively.The TA motor units were characterized by their recruitment threshold and minimal firing frequency and the effect of the sural nerve stimulation was subsequently investigated. Early recruited low frequency motor units were found to be inhibited, whereas later recruited motor units with a higher minimal firing frequency were facilitated. Similarly small TA H‐reflexes were inhibited, whereas large reflexes were facilitated.This difference in the effect of the sural nerve stimulation was not caused by a difference in the descending command, since the same early recruited motor unit was still inhibited when firing at a high frequency and at a high torque level.Stimulation of the femoral nerve was found to produce a monosynaptic facilitation of the TA H‐reflex and a heteronymous monosynaptic peak in the PSTH of single motor units. A stimulation of the sural nerve increased the size of the reflex facilitation, but had no effect on the size of the monosynaptic peak in the PSTH of the single motor units.It is concluded that the effect of the sural nerve stimulation on human TA motor units is similar to observations in the cat and that a similar interneuronal system may be responsible. It is furthermore suggested that the sural nerve stimulation increases the recruitment gain of the TA motoneuronal pool.
An analysis of synaptic transmission to motoneurones in the cat spinal cord using a new selective receptor blocker
Authors: ENGBERG I. , TARNAWA I. , DURAND J. , OUARDOUZ M. 
Published: December 2008

We have investigated the role of α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionate (AMPA) receptors on synaptic transmission in vivo between Ia primary afferents and cat spinal motoneurones using a selective non‐N‐methyl‐d‐aspartate (non‐NMDA) receptor antagonist, GYKI 52466.Both microionophoretic and intravenous application of GYKI 52466 depressed the Ia excitatory post‐synaptic potential (Ia EPSP) in a dose‐dependent manner, without any apparent effect on membrane conductance or resting potential of the motoneurone.GYKI 52466 reduced selectively α‐amino‐3‐hydroxy‐5‐methyl‐4‐isoxazolepropionate (AMPA)‐ but not N‐methyl‐d‐aspartate (NMDA)‐induced depolarizations.Our results suggest that a large part of the Ia EPSP is mediated by AMPA receptors. The participation of other excitatory amino‐acid receptors in the Ia EPSP is also discussed.
Regulation of early response genes in pancreatic acinar cells: external calcium and nuclear calcium signalling aspects
Authors: Fedirko N. , Gerasimenko J. V. , Tepikin A. V. , Gerasimenko O. V. 
Published: December 2008

AbstractNuclear calcium signalling has been an important topic of investigation for many years and some aspects have been the subject of debate. Our data from isolated nuclei suggest that the nuclear pore complexes (NPCs) are open even after depletion of the Ca2+ store in the nuclear envelope (NE). The NE contains ryanodine receptors (RyRs) and Ins(1,4,5)P3 receptors [Ins(1,4,5)P3Rs], most likely on both sides of the NE and these can be activated separately and independently: the RyRs by either NAADP or cADPR, and the Ins(1,4,5)P3Rs by Ins(1,4,5)P3. We have also investigated the possible consequences of nuclear calcium signals: the role of Ca2+ in the regulation of immediate early genes (IEG): c‐fos, c‐myc and c‐jun in pancreatic acinar cells. Stimulation with Ca2+‐mobilizing agonists induced significant increases in levels of expression. Cholecystokinin (CCK) (10 nm) evoked a substantial rise in the expression levels, highly dependent on external Ca2+: the IEG expression level was lowest in Ca2+‐free solution, increased at the physiological level of 1 mm [Ca2+]o and was maximal at 10 mm [Ca2+]o, i.e.: 102 ± 22% and 163 ± 15% for c‐fos; c‐myc −73 ± 13% and 106 ± 24%; c‐jun −49 ± 8% and 59 ± 9% at 1 and 10 mm of extracellular Ca2+ respectively. A low CCK concentration (10 pm) induced a small increase in expression. We conclude that extracellular Ca2+ together with nuclear Ca2+ signals induced by CCK play important roles in the induction of IEG expression.
Quality assurance evaluation of delivery of respiratory‐gated treatments
Authors: Cardenas Alex , Fontenot Jonas , Forster Kenneth M. , Stevens Craig W. , Starkschall George 
Published: December 2008

We describe a method for evaluating the quality of respiratory‐gated radiation delivery using a commercially available device. During irradiation, gating traces for one field for each treatment were extracted from the system for each of 14 patients. The data were then transferred to a spreadsheet. Software was developed to evaluate the following parameters: duty cycle, amplitude of fiducial motion, fraction of amplitude of motion during gated delivery, and respiratory cycle time. Criteria were established for acceptability of gating traces. In our sample, over 85% of the traces indicated acceptability. An example of results for one patient extracted from analyzed gating traces is as follows: mean duty cycle, 57%; average amplitude of motion, 0.89 cm; average fraction of motion during gated delivery, 0.45; mean respiratory cycle time, 4.5 s. This technique can be used to evaluate delivery of respiratory‐gated radiation therapy for quality assurance purposes and to assess various techniques for improving delivery of gated therapy. A hard copy of the gating traces can be used to document gated treatment delivery for potential billing of the gated delivery process.PACS numbers: 87.53‐j, 87.53.Tf
Improving a scissor‐action couch for conformal arc radiotherapy and radiosurgery
Authors: Li Kaile , Yu Cedric X. , Ma Lijun 
Published: December 2008

We have developed a method to improve the setup accuracy of a Varian Clinac 6/100 couch for delivering conformal arc therapy using a tertiary micro multileaf collimator (MLC) system. Several immobilization devices have been developed to improve the mechanical stability and isocenter alignment of the couch: turn‐knob harnesses, double‐track alignment plates, and a drop‐in rod that attaches the couch to the concrete floor. These add‐on components minimize the intercomponent motion of the couch's scissor elevator, which allows consistent treatment setup. The accuracy of our isocenter couch alignment is an improvement over the above devices, within 1 mm of their accuracy. The couch has been used with over 15 patients and with over 50 modulated conformal arc treatment deliveries at our institution.PACS numbers: 87.53.Kn, 87.53.Ly, 87.56.Da
HDR brachytherapy combined with 3D conformal versus IMRT in left‐sided breast cancer patients including internal mammary chain: Comparative analysis of dosimetric and technical parameters
Authors: Kinhikar Rajesh Ashok , Deshpande Sudesh Sharad , Mahantshetty Umesh , Sarin Rajiv , Shrivastava Shyam Kishore , Deshpande Deepak Dattatraya 
Published: December 2008

Treatment of the internal mammary chain (IMC) with radiation therapy (RT) for patients with breast cancer remains a controversial issue. Different treatment techniques have been proposed, including oblique electrons, electron‐photon combination, and partially wide tangents (PWTs). However, the residual heart dose can remain significant mainly for left‐sided lesions. With PWTs and intensity‐modulated radiotherapy (IMRT), respiratory movement and errors in IMC localization remain a problem. The goal of this paper is to evaluate the impact of IMC brachytherapy (IMCBT) combined with 3D conformal radiotherapy (3DCRT) planning on heart, lung, and contralateral breast doses compared with IMRT. All plans including IMCBT plus 3DCRT were done on PLATO; IMRT plans were generated using the Cadplan‐Helios inverse treatment‐planning software module with the “sliding window&rdquo; technique. Dose‐volume histograms (DVHs) were calculated for all volumes of interest. Conformity and homogeneity index was also calculated for the planning target volume (PTV). Dose distribution in the surrounding normal tissue was evaluated. The mean conformity of the PTV was found to be 1.06 with IMCBT plus 3DCRT and 1.12 with IMRT. The mean homogeneity (HI95/107) was found to be 1.4 with IMCBT plus 3DCRT and 3.32 with IMRT. Using the IMCBT plus 3DCRT technique, the mean dose to the heart, contralateral breast, ipsilateral lung, and contralateral lung decreased with values of 32%, 6.76%, 20% and 5.52%, respectively, compared with IMRT. This novel technique of IMCBT plus 3DCRT can potentially reduce the dose to the heart and lungs. In addition, it rivals IMRT because of its unique advantages in localization, obviating the need for respiratory gating and maximum sparing of heart and other structures.PACS numbers: 87.53.Jw, 87.53.Kn, 87.53.Mr, 87.53, 87.53.Tf