Gray matter metabolism in acute and chronic hydrocephalus.

Although hydrocephalus is usually considered a disorder of periventricular white matter, disturbance of gray matter is probably also involved. However, so far gray matter metabolism has not been studied in experimental hydrocephalus using high resolution in vivo magnetic resonance spectroscopy (MRS). Therefore 15 rats were made hydrocephalic by injection of 0.1 ml kaolin into the cisterna magna, whereas 10 sham-operated rats served as controls. (1)H MRS and magnetic resonance imaging were performed longitudinally in acute hydrocephalus 2 and 4 weeks after kaolin treatment and in chronic hydrocephalus after 6 weeks. Volumes of interest included the gray matter regions cortex, thalamus and hippocampus. In hydrocephalic animals, (1)H MRS revealed decreased glutamate levels in all examined areas at all time points. Moreover, in acute hydrocephalus disturbances were noted in the hippocampus with decreased concentrations of N-acetyl aspartate, creatine, inositol and taurine, and in the cortex with decreased taurine levels. A clear lactate peak was detected in CSF spectra from hydrocephalic rats. In addition, T2-weighted images showed increase of free water in the hippocampus. It can be concluded that glutamate metabolism is deranged in gray matter in acute and chronic hydrocephalus in rats. If confirmed in humans, early detection of glutamatergic disturbances and lactate accumulation using in vivo(1)H MRS might serve as an indication for surgical treatment of hydrocephalus before irreversible neuronal damage develops.

1,25-dihydroxyvitamin D-3 and 24,25-dihydroxyvitamin D-3 affect parathormone (PTH) -sensitive adenylate cyclase activity and alkaline phosphatase secretion of osteoblastic cells through different mechanisms of action.

In UMR 106 rat osteosarcoma cells, parathormone (1-34hPTH) and calcitonin (sCT) stimulated adenylate cyclase (AC) activity 5.5-and 2.8-fold, respectively. AC in osteoblasts (OB) from collagenase-treated calvaria of 3-day-old rats responded similarly to 1-34hPTH. In contrast, fibroblasts (mouse fibroblastomas) displayed a marginal 1-34hPTH sensitive AC. Osteoclasts (OC) of collagenase-treated rat calvariae, rat monocytes and mouse macrophages did not demonstrate 1-34hPTH inducable AC activity. Physiological concentrations of 24,25-dihydroxyvitamin D-3 attenuated PTH-sensitive AC in OB and UMR 106 cells within 20 min, while 1,25-dihydroxyvitamin D-3 showed no such immediate effect. In contrast, the AC response to Gpp(NH)p was unaffected by 24,25-(OH)2D3, indicating that 24,25-(OH)2D3 interrupts the coupling of the PTH receptor to the GTP binding protein Gs. OB and UMR 106 cells were also subjected to long-term (48 h) incubation with vitamin D-3 metabolites, 1-34hPTH or 20% serum from patients with secondary hyperparathyroidism (sHBT-serum), respectively. PTH-sensitive AC was markedly attenuated by pre-exposure to both 1-34hPTH and 1,25-(OH)2D3, while minimally affected by corresponding 24,25-(OH)2D3 and 20% sHPT-serum treatment. The secretion of alkaline phosphatase (Alphos) from the two cell types was strongly increased by 1-34hPTH, the effect being abolished by the presence of 24,25-(OH)2D3. Iliac crest biopsies of normal individuals exhibited a clear negative correlation between PTH-sensitive AC and corresponding serum 24,25-(OH)2D3 levels. Basal AC activity was, however, negatively correlated to serum 1,25-(OH)2D3 concentrations. In summary, the results show that 24,25-(OH)2D3 reduces PTH-stimulated AC activity in and Alphos secretion from osteoblastic bone cells by rapidly and directly interfering with the plasma membrane. These data reinforce the probable in vivo significance of 24,25-(OH)2D3. Moreover, the negative correlation between basal AC activity and serum 1,25-(OH)2D3 levels indicates a possible role for 1,25-(OH)2D3 in regulating bone cell synthesis of AC components in vivo.

Differences in neurotransmitter synthesis and intermediary metabolism between glutamatergic and GABAergic neurons during 4 hours of middle cerebral artery occlusion in the rat: the role of astrocytes in neuronal survival.

Astrocytes are intimately involved in both glutamate and gamma-aminobutyric acid (GABA) synthesis, and ischemia-induced disruption of normal neuroastrocytic interactions may have important implications for neuronal survival. The effects of middle cerebral artery occlusion (MCAO) on neuronal and astrocytic intermediary metabolism were studied in rats 30, 60, 120, and 240 minutes after MCAO using in vivo injection of [1-13C]glucose and [1,2- 13C]acetate combined with ex vivo 13C magnetic resonance spectroscopy and high-performance liquid chromatography analysis of the ischemic core (lateral caudoputamen and lower parietal cortex) and penumbra (upper frontoparietal cortex). In the ischemic core, both neuronal and astrocytic metabolism were impaired from 30 minutes MCAO. There was a continuous loss of glutamate from glutamatergic neurons that was not replaced as neuronal glucose metabolism and use of astrocytic precursors gradually declined. In GABAergic neurons astrocytic precursors were not used in GABA synthesis at any time after MCAO, and neuronal glucose metabolism and GABA-shunt activity declined with time. No flux through the tricarboxylic acid cycle was found in GABAergic neurons at 240 minutes MCAO, indicating neuronal death. In the penumbra, the neurotransmitter pool of glutamate coming from astrocytic glutamine was preserved while neuronal metabolism progressively declined, implying that glutamine contributed significantly to glutamate excitotoxicity. In GABAergic neurons, astrocytic precursors were used to a limited extent during the initial 120 minutes, and tricarboxylic acid cycle activity was continued for 240 minutes. The present study showed the paradoxical role that astrocytes play in neuronal survival in ischemia, and changes in the use of astrocytic precursors appeared to contribute significantly to neuronal death, albeit through different mechanisms in glutamatergic and GABAergic neurons.

Efficient secretion of human parathyroid hormone by Saccharomyces cerevisiae.

A cDNA encoding mature human parathyroid hormone (hPTH) was expressed in Saccharomyces cerevisiae, after fusion to the prepro region of yeast mating factor alpha (MF alpha). Radioimmunoassay showed high levels of hPTH immunoreactive material in the growth medium (up to 10 micrograms/ml). More than 95% of the immunoreactive material was found extracellularly as multiple forms of hormone peptides. Three internal cleavage sites were identified in the hPTH molecule. The major cleavage site, after a pair of basic amino acids (aa) (Arg25Lys26 decreases Lys27), resembles that recognized by the KEX2 gene product on which the MF alpha expression-secretion system depends. The use of a protease-deficient yeast strain and the addition of high concentrations of aa to the growth medium, however, not only changed the peptide pattern, but also resulted in a significant increase in the yield of intact hPTH (1-84) (more than 20% of the total amount of immunoreactive material). The secreted hPTH (1-84) migrates like a hPTH standard in two different gel-electrophoretic systems, co-elutes with standard hPTH on reverse-phase high-performance liquid chromatography, reacts with two hPTH antibodies raised against different parts of the peptide, has a correct N-terminal aa sequence, and has full biological activity in a hormone-sensitive osteoblast adenylate cyclase assay.

Universal or selective screening of the neonatal hip using ultrasound? A prospective, randomised trial of 15,529 newborn infants.

The aim of this study was to evaluate whether universal (all neonates) or selective (neonates belonging to the risk groups) ultrasound screening of the hips should be recommended at birth. We carried out a prospective, randomised trial between 1988 and 1992, including all newborn infants at our hospital. A total of 15 529 infants was randomised to either clinical screening and ultrasound examination of all hips or clinical screening of all hips and ultrasound examination only of those at risk. The effect of the screening was assessed by the rate of late detection of congenital or developmental hip dysplasia in the two groups. During follow-up of between six and 11 years, only one late-detected hip dysplasia was seen in the universal group, compared with five in the subjective group, representing a rate of 0.13 and 0.65 per 1,000, respectively. The difference in late detection between the two groups was not statistically significant (p = 0.22). When clinical screening is of high quality, as in our study, the effect of an additional ultrasound examination, measured as late-presenting hip dysplasia, is marginal. Under such circumstances, we consider that universal ultrasound screening is not necessary, but recommend selective ultrasound screening for neonates with abnormal or suspicious clinical findings and those with risk factors for hip dysplasia.

Hydrochemical distribution patterns in stream waters, Trøndelag, central Norway.

A regional geochemical sampling program of stream waters has been carried out in the Nord-Trøndelag region of central Norway. This area has hitherto been little affected by regional anthropogenic sources of pollution. Hydrochemical trends appear to be dominated by interplay of two main factors: (i) input of sea salts via marine aerosols in precipitation: and (ii) geological sources (mineral weathering). Factor (i) results in a predominance of Na-Cl waters near the coast, and may also be partially responsible (via proton displacement from soil ion-exchange sites by marine cations) for lower pH values in near-coastal waters. Further inland, the importance of marine salts decreases and waters become dominantly Ca-(Na)-HCO3. Sub-regional anomalies in geochemical maps for, e.g. nitrate and copper may indicate anthropogenic sources for these parameters from agriculture or mining activities.

Chylous complications after abdominal aortic surgery.

Two patients developed chylous complications following abdominal aortic aneurysm repair. One patient had chylous ascitis and was successfully treated by a peritoneo-caval shunt. The other patient developed a lymph cyst, which gradually resorbed after puncture. Chylous complications following aortic surgery are rare. Patients in bad a general condition should be treated by initial paracentesis and total parenteral nutrition, supplemented by medium-chain triglyceride and low-fat diet. If no improvement is observed on this regimen, the next step should be implementation of a peritoneo-venous shunt, whereas direct ligation of the leak should be reserved for those who are not responding to this treatment.

Selective carotid angiography during cross-clamping of the descending thoracic aorta in pigs.

OBJECTIVE: To visualize the intra- and extracranial blood vessels during cross-clamping of the descending thoracic aorta. EXPERIMENTAL DESIGN: Experimental animal study. SETTING: Animal laboratory, University Hospital. MATERIALS: Seven pigs. INTERVENTIONS: Cross-clamping of the descending thoracic aorta for 30 minutes. METHOD: Selective carotid angiography was performed before, during and after cross-clamping. Venous filling time of internal- and external jugular veins, diameter of internal and external jugular veins and internal, external and common carotid arteries and contrast intensity were determined. RESULTS: During cross-clamping the blood flow velocity increased as demonstrated by decreased venous filling time and decreased contrast intensity. In addition, the diameter of the external jugular vein increased and the diameter of the internal carotid artery decreased during cross-clamping. No arteriovenous anastomoses could be detected during the experiment. CONCLUSIONS: Our results indicate increased intra- and extracranial blood flow during cross-clamping of the descending thoracic aorta in pigs.

New World Stictocladius Edwards (Diptera: Chironomidae).

The orthocladiine Chironomidae genus Stictocladius Edwards was described originally from South America. Although recognised subsequently as present also in Australia and New Zealand, the true diversity in the Neotropics has remained unclear. After more than a decade of collections of both isolated adults and aquatic immature stages, we can recognise several new taxa and associate some immature stages. Thus, we describe Stictocladius prati n. sp. as male, female, pupa and larva; Stictocladius acutus n. sp. and Stictocladius acrilobus n. sp. as male, female and pupa; Stictocladius fimbriatus n. sp. as male and female; Stictocladius fovigus n. sp. and Stictocladius nudiventer n. sp. as male and pupa; and Stictocladius privicalcar n. sp. and Stictocladius prostatus n. sp. each as male imago alone. The male and female of Stictocladius pulchripennis Edwards is redescribed and the pupa described. The male and female of Stictocladius flavozonatus Edwards and the male of Stictocladius calonotum Edwards are described. Five pupal types are described: Stictocladius sp. A (near S. acrilobus), Stictocladius sp. B (possibly S. calonotum), Stictocladius sp. C (near S. calonotum), Stictocladius sp. D (possibly S. flavozonatus) and Stictocladius sp. E with uncertain affinity. A larva from Chile of the Stictocladius 'sofour type' (Stictocladius sp. F) and an unreared larva from North America (Stictocladius sp. G) possibly belonging to S. acutus are described. Keys to named Neotropical male and female imagines of Stictocladius and to all pupal forms of Neotropical Stictocladius are provided. Some data concerning fourth instars of Stictocladius are presented. Means of differentiation from putative sister taxon Lopescladius are discussed.

Regional distribution of blood flow during proximal aortic cross-clamping: an experimental study using coloured microspheres.

OBJECTIVE: To investigate the effect of thoracic aortic cross-clamping on blood perfusion of the brain, spinal cord, heart, muscular tissue and visceral organs. MATERIAL AND METHODS: Nine pigs underwent 30 min cross-clamping of the descending thoracic aorta. Multiple coloured microspheres (15.0 microm +/- 0.1) were infused into the left ventricle before and during aortic cross-clamping (XC) and after declamping (DC). Tissue samples were analysed by spectrophotometry. RESULTS: Blood perfusion of the middle and lower segments of the spinal cord was significantly reduced during aortic XC. Perfusion of the brain was not significantly altered by aortic XC, while perfusion of myocardium increased 3-fold. During XC, perfusion of the deltoid muscle and diaphragm increased 5-fold and 13-fold, respectively, while a decrease was found in the gluteus muscle. Renal blood flow was significantly reduced during XC. Finally, XC induced a significant decrease of perfusion in the bowel, spleen, liver and pancreas. CONCLUSION: During XC of the thoracic aorta, the perfusion of the muscular tissue was significantly increased proximal to the level of XC. The circulation of the brain was unchanged, probably because of autoregulatory mechanisms. Blood perfusion of the myocardium increased 3-fold during XC.

Quality of data reported on abdominal aortic aneurysm repair--a comparison between a national vascular and a national administrative registry.

OBJECTIVE: To study consistency of data and completeness of reporting in a national vascular registry, NorKar, and a national administrative registry, The Norwegian patient register (NPR). DESIGN: Comparative registry-based national study supplemented with a comprehensive control of patients registered in one major hospital. MATERIAL: All patients registered with a procedure-code for treatment of AAA in NorKar or NPR during 2001 or 2002, were included. METHOD: We compared the reporting of procedure-codes, diagnosis-codes and in-hospital deaths after treatment for abdominal aortic aneurysm (AAA) in the two registries to evaluate completeness. Consistency between procedure-codes and diagnoses were evaluated within both registries. Completeness of reporting to one NorKar Local Registry was investigated in more detail in one of the hospitals. RESULTS: Compared with the NPR numbers, NorKar contained 69% of the patients treated for AAA in Norway, while completeness for NorKar member hospitals was 84%. The detailed investigation in one of the hospitals showed a completeness of 91% and a false inclusion of 5.3% of all cases treated for AAA. The consistency between procedure-codes and diagnosis-codes was 93% in both registries. We found evidence of substantial underreporting of in-hospital deaths to NorKar in several hospitals. Overall reporting of early deaths to NorKar relative to completeness of reported cases was estimated to 72%. CONCLUSION: There is an underreporting of patients with AAA to NorKar according to the NPR numbers and a need for better control of procedure-diagnosis consistency in both registries. There seems to be a substantial underreporting of early deaths to NorKar. Introduction of unique patient-identifiable data could improve the quality of both registries by making matching of data possible.

Changes in hemodynamics and acid-base balance during cross-clamping of the descending thoracic aorta. A study in patients operated on for thoracic and thoracoabdominal aortic aneurysm.

AIM OF THE STUDY: In the clinical situation there is discrepancy between various investigations regarding the cardiac response of thoracic aortic cross-clamping. The aim was therefore to investigate the hemodynamic response and blood gases during proximal aortic cross-clamping (XC) in patients operated for descending thoracic and thoracoabdominal aortic aneurysm without circulatory support. PATIENTS AND METHODS: Altogether 51 patients operated on for thoracoabdominal (n=31) or descending thoracic aortic aneurysm (n=20) were included in the investigation. All patients were operated with aortic XC, but no circulatory support was applied. Hemodynamic variables and blood gases were recorded before and during XC. RESULTS: A significant increase in cardiac output during XC from 4.7 to 6.0 liters/min was observed (p<0.01). There was a similar percentual increase in heart rate and also the proximal systolic blood pressure increased. A metabolic acidosis occurred during XC. CONCLUSION: Cardiac output was significantly increased during XC in patients operated on for thoracoabdominal or descending thoracic aneurysm using direct aortic XC without circulatory support. Simultaneously, the heart rate was increased and there was a hyperdynamic circulatory state proximal to the aortic clamp. Redistribution of the blood volume in addition to catecholamine release may be responsible for the observed changes. These observations may influence the selection of operative strategy for some of these patients.

Problems related to previous thrombendarterectomy of the aorto-ilio-femoral arterial segment.

Early postoperative problems following aorto-ilio-femoral thrombendarterectomy include occlusion, bleeding and emboli. Technical details important for the prevention of these complications are discussed. Late problems include reobstruction, sexual dysfunction and aneurysm formation, the last complication being unusual following thrombendarterectomy. Late reobstruction is usually caused by progression of atherosclerosis and technical failures. Bypass grafting using synthetic material is usually the preferred method in redo aorto-ilio-femoral reconstruction since extensive dissection of the arteries is then avoided. We prefer a regular laparotomy for these operations. It might be an advantage to introduce ureteral stents making it easier to identify the ureter which may be surrounded by scar tissue following previous dissection. The creation of sufficient run-off is important. In several cases the procedure must therefore be supplemented with a profunda artery reconstruction. In case of localized and moderate obstruction PTA may be indicated for the relief of recurrent arterial obstruction following thrombendarterectomy.

Lipids of North Atlantic krill.

The seasonal variations in the total lipid content, lipid class composition, fatty acid composition, and fatty alcohol composition of Meganyctiphanes norvegica (M. Sars), Thysanoessa inermis (Krøyer), and T. raschii (M. Sars) have been examined. The total lipid content was highest in the autumn and early winter months and lowest in the spring. In M. norvegica, triacylglycerols served as the only depot lipids, whereas in T. inermis and T. raschii triacylglycerols, wax esters, and glycerophospholipids varied in proportion to the total lipid content. This suggests that glycerophospholipids, as well as wax esters and triacylglycerols, constitute depot lipids in these species. Wax esters and glycerophospholipids were the dominating depot lipids in T. inermis, whereas triacylglycerols and glycerophospholipids were most important in T. raschii. Results suggest that non-depot glycerophospholipids may constitute 3.5-4.5% of the dry weight of the three species of krill examined. T. inermis and T. raschii, from the same catches, had very similar fatty acid compositions for each of the major lipid classes, with the exception of a few minor fatty acids. The major lipid classes in all three species showed complex seasonal variations in the content of the fatty acids that typically reflect the diet, particularly in the case of the triacylglycerols. The results suggest that all the species examined are more herbivorous during the summer than during the autumn and winter. M. norvegica seemed to be significantly more carnivorous than the two Thysanoessa species. The degree of incorporation of individual fatty acids from the diet is probably specific for each lipid class in each krill species. The proportion of polyenoic fatty acids in the glycerophospholipids and the proportion of monoenoic fatty acids in the wax esters may be of importance for the temperature adaptation of T. inermis and T. raschii.

Isolated necrosis of the common bile duct subsequent to irradiation and chemotherapy. Case report.

A 35-year-old man with malignant lymphoma of the skeleton was irradiated towards the first lumbar vertebra. Courses of cytotoxic drugs were given as the disease progressed. Isolated, nonliquefying necrosis of the common bile duct developed. A combined irradiation and drug effect is suggested as the cause of the necrosis.

[Vascular surgery in Norway in 1986]. / Karkirurgi i Norge 1986.

A questionnaire on vascular surgical activity in 1986 was sent to all Norwegian surgical departments (80). 78 units responded. Vascular surgery is not performed in the two hospitals who did not respond. Altogether 3,509 vascular operations were performed in 1986 (844 operations per million inhabitants). By comparison, 2,529 operations were performed in 1981, 2,039 in 1978 and 1,100 in 1975. The largest increase was recorded in operations for abdominal aortic aneurysm, carotid artery stenosis, arterial emboli and angio-access surgery. Elective vascular operations were performed in 41 departments, whereas an additional 16 did emergency vascular surgery only. 34% of the operations were performed by members of the junior staff. Differences between the five health regions have decreased since the investigation in 1981. The highest activity was observed in Health Region V, where 986 operations were performed per million inhabitants. Vascular surgical activity is increasing in Norway. This must be taken into account when estimating the number of residencies and staff positions for vascular surgery. The increasing need for vascular surgery should also influence priorities in our national health system.

Cerebral haemodynamics during proximal aortic cross-clamping.

This study was carried out to examine cerebral blood flow, including the microcirculation and intracranial pressure during cross-clamping (XC) of the thoracic aorta in pigs. Blood flow in the internal carotid artery was measured by electromagnetic flowmetry. Cerebral microcirculation was studied by the laser Doppler technique, and intracranial pressure measured by applying a fibre optic pressure monitoring catheter in the same craniotomy. Maximal and mean blood flow velocity of the middle cerebral artery was recorded using a transcranial Doppler and cardiac output measured by thermodilution. The thoracic aorta was cross-clamped distal to the left subclavian artery for 30 min. During aortic XC the internal carotid artery blood flow increased 191% (p less than 0.05). Simultaneously mean and maximal blood flow velocity of the middle cerebral artery both increased 125% (p less than 0.01). Intracranial pressure increased 163% (p less than 0.05), and there was an increase in cerebral flux of 23% (p less than 0.05). Within the first minutes following the release of XC, all values decreased to preocclusive values. In conclusion, we observed a significant increase in cerebral blood flow during XC of the thoracic aorta. This is in accordance with the finding of a simultaneous increase in cardiac output. These haemodynamic changes support the theory that an increased blood flow via the proximal feeding system to the anterior spinal artery might be important in avoiding neurological sequelae following proximal aortic XC.

Microdialysis of the spinal cord during thoracic aortic cross-clamping in a porcine model.

OBJECTIVE: Utilising microdialysis to measure the changes of glucose, lactate, pyruvate and glutamate levels in the spinal cord after cross-clamping of the thoracic aorta in an established porcine model to monitor the degree of ischaemia. DESIGN: Experimental study with a porcine model. SETTING: University Hospital, Trondheim. SUBJECTS: Six pigs. MAIN OUTCOME MEASURE: Lactate, pyruvate and glutamate concentrations in the microdialysis perfusate from the spinal cord. RESULTS: A significant increase of the lactate-pyruvate ratio during the last 30 min of the 1 h clamping period, with a maximum increase of 169% from the basal value the last 10 min before declamping. No evident change in this ratio between the clamping and the reperfusion period. No significant change in glutamate levels during clamping or reperfusion period. CONCLUSION: Microdialysis reflects the ischaemic state of the spinal cord during cross-clamping of the thoracic aorta in pigs, and is well suited to study each phenomena.

Shunting of the coeliac and superior mesenteric arteries during thoracoabdominal aneurysm repair.

OBJECTIVES: To describe our experience with shunting of the coeliac and superior mesenteric arteries during thoracoabdominal aneurysm repair. DESIGN: Retrospective study. MATERIAL: Eight patients undergoing resection and graft replacement of Crawford type III (5) and type IV (3) thoracoabdominal aortic aneurysms were included in this series. One patient had rupture, four were symptomatic and three were operated on electively. METHODS: A vascular graft with a sidearm was applied for the reconstructions. A T-shunt was connected to the sidearm. Following completion of the proximal anastomosis the shunt was inserted into the coeliac and superior mesenteric arteries. The anastomoses to these arteries and the renal arteries were then completed. Finally the distal anastomosis was performed. RESULTS: There was no early mortality (30 days). One patient had postoperative paraparesis, but recovered quite well. Reoperation became necessary due to sigmoid necrosis in one patient and due to haemorrhage in another. During the follow-up period four patients died but the other patients are alive between 3 and 8 years after surgery. CONCLUSION: The application of shunting of the superior mesenteric and coeliac arteries during thoracoabdominal aortic surgery is feasible and the results have been acceptable. Further investigation of the optimal blood flow needed to avoid intestinal ischaemia in a larger series of patients is desirable.

Effect of sodium nitroprusside on cardiac output during cross-clamping of the descending thoracic aorta in pigs.

Sodium nitroprusside (SNP) is used to control proximal hypertension during cross-clamping of the descending thoracic aorta (XC). To assess the haemodynamic effects of SNP on cardiac output (CO) during XC, 21 pigs were anaesthetized with ketamine and fentanyl. In the control group (n = 11), no vasodilating therapy was given. In the investigation group (SNP group), 2 animals died during the surgical preparation and were excluded, leaving 8 animals in the group (n = 8). In these animals, SNP was infused in order to keep the mean arterial pressure (MAP) at about 100 mm Hg during cross-clamping. In both groups, aorta was cross-clamped for 30 min, and cardiac output (CO) was measured by the thermodilution technique. Following cross-clamping, CO increased 107% in the control group and 96% in the SNP group. There was an increase in heart rate (HR) of 77% in the control group and of 110% in the SNP group, and a reduction in systemic vascular resistance of 41% in the SNP group. Stroke volume (SV) was unchanged in both groups. MAP increased 83% in the control-group. No differences were observed between the two groups regarding central venous pressure or pulmonary artery pressure. Four animals in the SNP group died 5-10 min after release of the aortic clamp. In conclusion, we found equal increase in CO in both groups. The increase in CO was related predominantly to increased HR, whereas SV was largely unaltered. Vasodilation with SNP increased the mortality following clamp removal in this experimental model.