摘要:

IVERSEN, P. O. 1997. Blood flow to the haemopoietic bone marrow.Acta Physiol Scand159, 269–276. Received 25 September 1996, accepted 14 October 1996. ISSN 0001–6772. Department of Physiology, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway.In order to maintain an adequate haemopoiesis, the bone marrow is dependent on a sufficient blood supply. Our understanding of the regulation of marrow perfusion remained patchy for several decades, mainly because of technological difficulties. Recent advances in methodology have permitted more detailed analyses of bone marrow perfusion.Enhanced stimulation of erythropoietic or leucopoietic activity leads to increased blood flow to the bone marrow. There is evidence that this vasodilatory effect is mediated by the cytokines erythropoietin and granulocyte colony‐stimulating factor; however, a direct link has yet to be firmly established. The presence of receptors for several other cytokines on vascular endothelial and smooth muscle cells suggests that these may also have a regulatory role. The vasodilating factor nitric oxide (NO) regulates bone marrow blood flow both under normal conditions and during accelerated haemopoiesis, and NO is possibly induced via activation of cytokine receptors. There are conflicting reports as to how catecholamines affect marrow vascular tone. Although there is firm evidence that the bone marrow vasculature is innervated, no definite role of this innervation in vasoregulation has been documented.Advances in bone marrow/blood stem cell transplantation technology and the development of other therapeutic strategies for bone marrow failure may in part be dependent on optimization of the blood supply to the haemopoietic bone m

ISSN:0001-6772    

DOI:10.1046/j.1365-201X.1997.00107.x

出版商:Blackwell Science Ltd.    

年代:1997

数据来源: WILEY

摘要:

THORLACIUS, H., FERNVIK, E., GAUTAM, N., LUNDAHL, J., RAUD, J., JACOBSON, S.H.&LINDBOM, L. 1997. Impaired leucocyte rolling, adhesion and transendothelial migration following cuprophane haemodialysis.Acta Physiol Scand159, 277–283, Received 29 July 1996, accepted 13 November 1996. ISSN 0001–6772. Department of Physiology and Pharmacology, Karolinska Institutet, Stockholm, Sweden.In this study, we investigated how different steps in the extravasation process of leucocytes, i.e. rolling, adhesion and transendothelial migration, are affected by haemodialysis with cuprophane membranes. Human leucocytes obtained from whole blood prior to clinical haemodialysis and from the afferent blood line (post‐dialyser) 15 min after the initiation of dialysis were injected into the mesenteric microcirculation of urethane anaesthetized rabbits and analysed for their ability to roll in the microvessels by use of intravital fluorescence microscopy. Moreover, neutrophils from the two leucocyte populations were compared with respect to chemoattractant‐induced adhesion and transmigration across confluent monolayers of bovine aortic endothelial cells. Our results show that, as compared with pre‐dialysis leucocytes, 15 min of cuprophane haemodialysis impaired leucocyte rolling by 78 ± 7%, reducedN‐formyl‐methionyl‐leucyl‐phenylalanin (fMLP)‐induced adhesion by 34 ± 9%, and abolished transendothelial migration. These findings demonstrate that intradialytical activation of leucocytes during cuprophane haemodialysis severely affects leucocyte functions that are critical in the extravasation process of these cells at inflammatory tissue sites, and thus may help explain the increased susceptibility to infections observed in

ISSN:0001-6772    

DOI:10.1046/j.1365-201X.1997.00119.x

出版商:Blackwell Science Ltd.    

年代:1997

数据来源: WILEY

摘要:

YUAN, S.‐Z., RUNOLD, M.&LAGERCRANTZ, H. 1997. Adrenalectomy reduces the ability of newborn rats to gasp and survive anoxia.Acta Physiol Scand159, 285–292. Received 28 March 1996, accepted 8 November 1996. ISSN 0001–6772. Department of Neuroscience, Karolinska Institute; Department of Respiratory and Allergic Diseases, Huddinge University Hospital; Department of Woman and Child Health, Karolinska Hospital, Stockholm, Sweden; Department of Obstetrics and Gynecology, Second Central Hospital, Tianjin, China.The ventilatory response to anoxia in unanaesthetized rat pups of 1 and 8 days of age was studied. Ventilation was recorded by barometric plethysmography. During acute anoxia (100% N2), animals of both ages responded with hyperpnoea, primary apnoea, hypoxic gasping and secondary apnoea. After secondary gasping, occasional gasps occurred. If oxygen was administered during the gasping period, all animals survived through autoresuscitation. The duration of the period of hypoxic gasping was significantly longer in the 1‐day‐old animals. Adrenalectomy reduced the length of this period in both 1‐ and 8‐day‐old animals. In a second series of experiments, the effect of adrenergic antagonists on autoresuscitation was examined. Pretreatment with the non‐selective α‐receptor antagonist phentolamine reduced the duration of gasping in 1‐day‐old rats, but prolonged this duration in 8‐day‐old rats. The non‐selective β‐receptor antagonist propranolol did not affect the duration of gasping in␣1‐day‐old rats, whereas it prolonged this period in the older animals. We conclude that proper duration of gasping during anoxia is dependent on intact adrenal function and that the adrenal glands therefore play an important role in autoresuscitation from anoxia during postnatal life. The underlying mechanism ap

ISSN:0001-6772    

DOI:10.1046/j.1365-201X.1997.00121.x

出版商:Blackwell Science Ltd.    

年代:1997

数据来源: WILEY

摘要:

NYHLÉN, K., RIPPE, B.&HULTKVIST‐BENGTSSON, U. 1997. An isolated blood‐perfused guinea‐pig lung model for simultaneous registration of haemodynamic, microvascular and respiratory variables.Acta Physiol Scand159, 293–302. Received 13 March 1996, accepted 19 September 1996. ISSN 0001–6772. Department of Preclinical Research, Gambro Lundia AB, Lund, Sweden and Department of Nephrology, University Hospital, Lund, Sweden.We have developed an optimized isolated lung perfusion system, which possesses several advantages. Firstly, studies of microvascular, respiratory, haematological and biochemical variables are combined in one model. Secondly, blood perfusion resulted in less oedema formation than buffer‐perfused lungs, and highPo2through ventilation with room air. Finally, data for the variables can be displayed, controlled and recorded in real time using a computerized system permitting subsequent processing (e.g. filtering without destroying original data). In this paper we discuss the basic behaviour of the model in terms of vascular resistance, vascular permeability, respiration and neutrophil sequestration. In addition, the effects of oleic acid, histamine and histamine receptor blockers were tested, and two methods of calculating vascular permeability are discussed. The way in which different anaesthetics affect the neutrophil content of lung tissue and blood was also investigated. In the model, oleic acid increased pulmonary vascular resistance and permeability, whereas histamine did not affect either permeability or the pre/postcapillary vascular resistance ratio. However, histamine receptor blockers increased this ratio, indicating that there was endogenous histamine release. The neutrophil content of the isolated lungs was increased, but this did not affect the variables measured. There was also accumulation of neutrophils in the lungs of blood donor animals, due to CO2sedation. However, CO2sedation proved to be superior to pentobarbital or ketamine anaesthesia in maintaining the levels of neutrophils circulating in the blood. In conclusion, this model seems to be sensitive and to yield reproducible results regarding the physiology or pathophysiology

ISSN:0001-6772    

DOI:10.1046/j.1365-201X.1997.00103.x

出版商:Blackwell Science Ltd.    

年代:1997

数据来源: WILEY

摘要:

Nieuwenhuizen, A. G., Schuiling, G. A., Moes, H.&Koiter, T. R. 1997. Role of increased insulin demand in the adaptation of the endocrine pancreas to pregnancy.Acta Physiol Scand159, 303–312. Received 8 July 1996, accepted 24 October 1996. ISSN 0001–6772. Department of Obstetrics and Gynaecology, University of Groningen, Groningen, the Netherlands.During gestation the demand for insulin increases due to a decrease in insulin sensitivity of the maternal tissues. Simultaneously, pancreatic islet‐cell proliferation, as well as insulin production and secretion increase. Both phenomena appear to be caused by the actions of pregnancy hormones. We studied the relationship between the two phenomena by investigating whether the supply of exogenous insulin affects the secretion of pregnancy hormones and islet function during gestation. For that purpose rats were treated with high doses of insulin (4.8 IU day−1by sub‐cutaneous osmotic mini pumps) so that the endogenous demand for insulin was fully satisfied from day 8–14 of gestation. Euglycaemia (5.0 mm) was maintained by intra venous infusion of glucose. The treatment suppressed insulin synthesis, as measured byin situhybridization, in both pregnant and cyclic rats. In addition, in pregnant rats the increments in insulin secretion and in islet‐cell proliferation were partly prevented. Furthermore, the data also suggest that in pregnant rats the treatment partly prevented the decrease in insulin sensitivity. Finally, the treatment did not affect the plasma concentrations of progesterone, prolactin and placental lactogen, but prevented the rise in growth hormone concentrations in pregnant rats. The present data suggest that, next to direct effects of pregnancy hormones and growth hormone on the pancreatic islets, a decreased insulin sensitivity in the maternal tissues, induced by actions of the same hormones, is involved in the regulation of islet functi

ISSN:0001-6772    

DOI:10.1046/j.1365-201X.1997.d01-1872.x

出版商:Blackwell Science Ltd.    

年代:1997

数据来源: WILEY

摘要:

Gastrin/CCK‐B receptors are involved in the regulation of several types of cells of the gastric mucosa, including the parietal cells, the ECL cells and the D cells. In this study, we aimed at localizing such receptors in the gastric mucosa. For this purpose, we prepared monospecific antibodies against two sequences of the canine gastrin/CCK‐B receptor. Sections of formalin‐fixed, paraffin‐embedded corpus and antrum from dog and guinea‐pig were immunostained with these antibodies. In parallel, sections were stained with antibodies against somatostatin. Staining with gastrin/CCK‐B receptor antibodies was observed in a few, small epithelial cells in the bottom part of the corpus mucosa. Immunoreactive cells of the antral mucosa were structurally similar, but more frequent. The same cells also stained with somatostatin antibodies. In addition, one of the gastrin/CCK‐B antibodies reacted with canine submucosal smooth muscle cells. No staining was observed in sections exposed to antibodies that were pre‐absorbed with the corresponding antigen. We conclude that gastrin/CCK‐B receptors are present in D cells of the gastric mucosa and in submucosal sm

ISSN:0001-6772    

DOI:10.1046/j.1365-201X.1997.114360000.x

出版商:Blackwell Science    

年代:1997

数据来源: WILEY

摘要:

STØA‐BIRKETVEDT, G., WALDUM, H. L.,VONEN, B.&FLORHOLMEN, J. 1997. Effect of cimetidine on basal and postprandial plasma concentrations of cholecystokinin and gastrin in humans.Acta Physiol Scand159, 321–325.Received 12 June 1996, accepted 8 November 1996. ISSN 000–6772. Laboratory of Gastroenterology, Institute of Clinical Medicine, University of Tromsø, Tromsø, Physiological Laboratory, University School of Medicine, 6000 Trondheim and Department of Surgery, University Hospital of Tromsø, 9037 Tromsø, Norway.Cimetidine reduces the appetite and weight in healthy overweight subjects. Gastrointestinal regulatory peptides such as cholecystokinin (CCK) have been proposed to mediate the satiety signal from gut to brain. Therefore, the effect of cimetidine on basal and postprandial plasma concentrations of cholecystokinin and gastrin was studied. After an overnight fast, 12 healthy volunteers were given cimetidine (400 mg) on day 1, breakfast on day 2, and cimetidine 20 min before breakfast on day 3. Plasma concentrations of cholecystokinin and gastrin were measured by radioimmunoassay. Plasma cholecystokinin concentration increased with one major peak observed 30 min and one smaller peak observed 120 min after intake of cimetidine. The meal induced an increase in the plasma concentration of cholecystokinin, while cimetidine prior to the meal elicited a sustained postprandial cholecystokinin response. Cimetine had no effect on the basal plasma concentration of gastrin. The meal induced an increase in the plasma concentration of gastrin, while cimetidine prior to the meal elicited a sustained postprandial gastrin response. In conclusion, cimetidine increases the basal concentration of plasma cholecystokinin and elicits a sustained postprandial response of both cholecystokinin and gastrin. At least the cholecystokinin response may be one mechanism by which cimetidine re

ISSN:0001-6772    

DOI:10.1046/j.1365-201X.1997.00122.x

出版商:Blackwell Science Ltd.    

年代:1997

数据来源: WILEY

摘要:

SHIOJIRI, T., SHIBASAKI, M., AOKI, K., KONDO, N.&KOGA, S. 1997. Effects of reduced muscle temperature on the oxygen uptake kinetics at the start of exercise.Acta Physiol Scand159, 327–333. Received 25 September 1995, accepted 5 November 1996. ISSN 0001–6772. Laboratory of Exercise and Sports Science, Yokohama City University; Division of Intelligence Science, Graduate School and Technology, Division of Education, Graduate School, Faculty of Human Development, Kobe University; and Applied Physiology Laboratory, Kobe Design University, Japan.The purpose of this study was to examine the effects of reduced muscle temperature (Tm ) on gas exchange kinetics and haemodynamics at the start of exercise. Six male subjects performed moderate cycle exercise under reduced (C) and normal (N)Tmconditions.Tmand rectal temperature were significantly reduced by immersion in cold water (by 6.6 °C and 1.8 °C, respectively). The increases in oxygen uptake (V˙o2) and oxygen pulse (V˙o2/HR) during phase 1 (abrupt increase after the start of exercise) were significantly lower under C than under N. The time constant for O2under C (36.0 ± 7.7 (SD) s) was significantly greater than under N (27.5 ± 4.4 s); however, the time constants of cardiac output under C (38.3 ± 16.6 s) and N (33.7 ± 18.5 s) were similar. These results suggest that the slowerV˙o2on‐response under reducedTmconditions is caused by decreased O2extraction in working muscle and/or by impairment of oxidati

ISSN:0001-6772    

DOI:10.1046/j.1365-201X.1997.00120.x

出版商:Blackwell Science Ltd.    

年代:1997

数据来源: WILEY

摘要:

MEEUSEN, R., SMOLDERS, I., SARRE, S., DE MEIRLEIR, K., KEIZER, H., SERNEELS, M., EBINGER, G.&MICHOTTE, Y. 1997. Endurance training effects on neurotransmitter release in rat stratium – anin vivomicrodialysis study.Acta Physiol Scand159, 335–341. Received 14 May 1996, accepted 15 November 1996. ISSN 0001–6772. Department of Human Physiology and Sports Medicine, Department of Pharmaceutical Chemistry and Drug Analysis, and Department of Neurology, University Hospital, Vrije Universiteit Brussel, Brussels, Belgium; Department of Movement Sciences, Rijksuniversiteit Limburg, Maastricht, the Netherlands.In the present study we use thein vivomicrodialysis sampling technique to register extracellular levels of neurotransmitters in the striatum of trained and untrained rats. We further evaluate the influence of 1 h of exercise on the striatal release of dopamine (DA), noradrenaline (NA), glutamate (GLU) and γ‐aminobutyric acid (GABA) in trained and untrained rats. Male Wistars were randomly assigned to a training or control group. The exercise training consisted of running on a treadmill for 6 weeks, 5 days week−1, with running time and speed gradually increased from 30 min at 19 m min−1during the first week to 80 min at 26 m min−1during the final training week. The animals of the control group were placed on the treadmill twice a week, and received a total of four `adaptation sessions', in which they exercised 15–45 min at 26 m min−1. Brain dialysates were analysed with microbore liquid chromatography (LC), with electrochemical detection (monoamines and GABA) and fluorescence detection (GLU). Soleus citrate synthase and basal striatal concentrations of DA, NA and GLU were significantly different between the trained and control animals. Sixty minutes of exercise significantly increased extracellular DA, NA and GLU levels in both groups, but there was no statistically significant difference in the exercise‐induced increase between trained and control animals. There was no statistical difference in basal or exercise‐induced GABA levels between trained and control animals. The results indicate that exercise training appears to result in diminished basal activity of striatal neurotransmitters, while maintaining the necessa

ISSN:0001-6772    

DOI:10.1046/j.1365-201X.1997.00118.x

出版商:Blackwell Science Ltd.    

年代:1997

数据来源: WILEY

ISSN:0001-6772    

DOI:10.1046/j.1365-201X.1997.00133.x

出版商:Blackwell Science Ltd.    

年代:1997

数据来源: WILEY