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- Lundberg, J. O. N., et al.
(författare)
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Increased nitric oxide production in collagenous and lymphocytic colitis
- 1997
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Ingår i: European Journal of Clinical Investigation. - : Wiley. - 0014-2972 .- 1365-2362. ; 27:10, s. 869-871
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Tidskriftsartikel (refereegranskat)abstract
- The production of nitric oxide (NO) is increased in active ulcerative colitis and in Crohn's disease. We have studied NO production in collagenous colitis (CC) and lymphocytic colitis (LC), both of which are inflammatory bowel disorders of unknown aetiology. NO levels were measured directly in gas sampled from the colon during colonoscopy. Plasma levels of NO metabolites (nitrate/nitrite) were also measured. Luminal NO levels were more than 100 times higher in patients with CC compared with controls. In addition, plasma levels of nitrate/nitrite were increased in the patients as compared with controls. Measurements of NO directly in the colon or its oxidation products in plasma may be a helpful tool in further understanding the role of NO in the pathophysiology of CC and LC. Moreover, it is tempting to speculate that these measurements could be clinically useful in the diagnosis and therapy monitoring of these two inflammatory bowel diseases.
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- AHLBORG, G, et al.
(författare)
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Circulating endothelin-1 reduces splanchnic and renal blood flow and splanchnic glucose production in humans
- 1995
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Ingår i: Journal of applied physiology (Bethesda, Md. : 1985). - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 79:1, s. 141-145
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Tidskriftsartikel (refereegranskat)abstract
- The effect of minimal changes in circulating plasma endothelin-1 (ET-1) was studied in 12 healthy subjects receiving either 60 min of ET-1 (0.2 pmol.kg-1.min-1) or physiological saline intravenously. Blood was drawn from arterial, renal, and central hepatic vein catheters. Arterial ET-1-like immunoreactivity (ET-1-LI) increased from 4.7 +/- 0.4 (SE) to 8.6 +/- 1.0 pmol/l during ET-1 infusion. After 10 min, plasma ET-1-LI had increased to 6.12 +/- 0.29 pmol/l. For comparison the plasma ET-1-LI level was 12.9 +/- 4.2 pmol/in five patients with sepsis syndrome. Mean arterial blood pressure rose from 92 +/- 3 to 99 +/- 4 mmHg. Estimated splanchnic and renal blood flows fell by 18 +/- 5 and 10 +/- 3%, respectively, and splanchnic glucose production fell by 42 +/- 6% within 10 min of the ET-1 infusion and differed compared with corresponding control values. Only estimated splanchnic blood flow had increased 60 min after the ET-1 infusion. No change in splanchnic uptake of lactate or glycerol was seen. In conclusion, we suggest that circulating ET-1 with small or no demonstrable change in plasma concentration interferes with vasoactivity and splanchnic glycogenolyses in health and possibly pathophysiological conditions.
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- AHLBORG, G, et al.
(författare)
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Metabolic and vascular effects of circulating endothelin-1 during moderately heavy prolonged exercise
- 1995
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Ingår i: Journal of applied physiology (Bethesda, Md. : 1985). - : American Physiological Society. - 8750-7587 .- 1522-1601. ; 78:6, s. 2294-2300
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Tidskriftsartikel (refereegranskat)abstract
- The aims were to investigate 1) the effects of endothelin-1 (ET-1) during exercise and 2) the influence of exercise on arterial ET-1 levels. Six healthy subjects performed two exercises of 2 h duration at 50% of peak oxygen uptake preceded by intravenous infusion of physiological saline or ET-1 (4 pmol.kg-1.min-1). Blood specimens were taken from arterial and hepatic vein catheters. Arterial ET-1 rose 15-fold during the infusion. Splanchnic blood flow fell after ET-1 and remained lower than in control subjects during exercise (P < 0.001). Splanchnic glucose production was approximately 25% lower compared with control values during the whole exercise period (P < 0.01). Neither heart rate, arterial glucagon, insulin, catecholamines, renin, glucose, lactate, nor glycerol levels differed from control exercise values. The calculated gluconeogenesis from glycerol and lactate did not differ from the control values. ET-1 levels rose approximately twofold in the control exercise (P < 0.01) and in another group of seven subjects performing 1 h of exercise at 70% of peak oxygen uptake (P < 0.001). In conclusion, ET-1 levels increased during exercise without ET-1 administration. In addition, circulating ET-1 has a (direct or indirect) regulatory action on splanchnic blood flow and glucose metabolism during exercise (and possibly under pathophysiological conditions) in humans.
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- Carlsson, S., et al.
(författare)
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Effects of pH, nitrite, and ascorbic acid on nonenzymatic nitric oxide generation and bacterial growth in urine
- 2001
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Ingår i: Nitric oxide. - : Elsevier BV. - 1089-8603 .- 1089-8611. ; 5:6, s. 580-586
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Nitrite may be generated by bacteria in urine during urinary tract infections. Acidification of nitrite results in the formation of nitric oxide (NO) and other reactive nitrogen oxides, which are toxic to a variety of microorganisms. We have studied NO formation and bacterial growth in mildly acidified human urine containing nitrite and the reducing agent vitamin C. Urine collected from healthy subjects was incubated in closed syringes at different pH values with varying amounts of nitrite and/or ascorbic acid added. NO generation was measured in headspace gas using a chemiluminescence technique. A similar setup was also used to study the growth of three strains of bacteria in urine. Mildly acidified nitrite-containing urine generated large amounts of NO and this production was greatly potentiated by ascorbic acid. The growth of Escherichia coli, Pseudomonas aeruginosa, and Staphylococcus saprophyticus was markedly reduced by the addition of nitrite to acidified urine. This inhibition was enhanced by ascorbic acid. In conclusion, we show that the growth of three common urinary pathogens is markedly inhibited in mildly acidified urine when nitrite is present. The bacteriostatic effect of acidified nitrite is likely related to the release of NO and other toxic reactive nitrogen intermediates. These results may help to explain the well-known beneficial effects of urinary acidification with, e.g., vitamin C in treatment and prevention of urinary tract infection.
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- Carlström, Mattias, et al.
(författare)
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Peritoneal dialysis impairs nitric oxide homeostasis and may predispose infants with low systolic blood pressure to cerebral ischemia
- 2016
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Ingår i: Nitric Oxide - Biology and Chemistry. - : Elsevier BV. - 1089-8603 .- 1089-8611. ; 58, s. 1-9
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Tidskriftsartikel (refereegranskat)abstract
- Background & purpose Infants on chronic peritoneal dialysis (PD) have an increased risk of developing neurological morbidities; however, the underlying biological mechanisms are poorly understood. In this clinical study, we investigated whether PD-mediated impairment of nitric oxide (NO) bioavailability and signaling, in patients with persistently low systolic blood pressure (SBP), can explain the occurrence of cerebral ischemia. Methods & results Repeated blood pressure measurements, serial neuroimaging studies, and investigations of systemic nitrate and nitrite levels, as well as NO signaling, were performed in ten pediatric patients on PD. We consistently observed the loss of both inorganic nitrate (-17 ± 3%, P < 0.05) and nitrite (-34 ± 4%, P < 0.05) during PD, which may result in impairment of the nitrate-nitrite-NO pathway. Indeed, PD was associated with significant reduction of cyclic guanosine monophosphate levels (-59.4 ± 15%, P < 0.05). This reduction in NO signaling was partly prevented by using a commercially available PD solution supplemented with l-arginine. Although PD compromised nitrate-nitrite-NO signaling in all cases, only infants with persistently low SBP developed ischemic cerebral complications. Conclusions Our data suggests that PD impairs NO homeostasis and predisposes infants with persistently low SBP to cerebral ischemia. These findings improve current understanding of the pathogenesis of infantile cerebral ischemia induced by PD and may lead to the new treatment strategies to reduce neurological morbidities.
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- Crespo, AS, et al.
(författare)
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Nasal nitric oxide and regulation of human pulmonary blood flow in the upright position
- 2010
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Ingår i: Journal of applied physiology (Bethesda, Md. : 1985). - : American Physiological Society. - 1522-1601 .- 8750-7587. ; 108:1, s. 181-188
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Tidskriftsartikel (refereegranskat)abstract
- There are a number of evidences suggesting that lung perfusion distribution is under active regulation and determined by several factors in addition to gravity. In this work, we hypothesised that autoinhalation of nitric oxide (NO), produced in the human nasal airways, may be one important factor regulating human lung perfusion distribution in the upright position. In 15 healthy volunteers, we used single-photon emission computed tomography technique and two tracers (99mTc and 113mIn) labeled with human macroaggregated albumin to assess pulmonary blood flow distribution. In the sitting upright position, subjects first breathed NO free air through the mouth followed by the administration of the first tracer. Subjects then switched to either nasal breathing or oral breathing with the addition of exogenous NO-enriched air followed by the administration of the second tracer. Compared with oral breathing, nasal breathing induced a blood flow redistribution of ∼4% of the total perfusion in the caudal to cranial and dorsal to ventral directions. For low perfused lung regions like the apical region, this represents a net increase of 24% in blood flow. Similar effects were obtained with the addition of exogenous NO during oral breathing, indicating that NO and not the breathing condition was responsible for the blood flow redistribution. In conclusion, these results provide evidence that autoinhalation of endogenous NO from the nasal airways may ameliorate the influence of gravity on pulmonary blood flow distribution in the upright position. The presence of nasal NO only in humans and higher primates suggest that it may be an important part of the adaptation to bipedalism.
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- Eriksson, LI, et al.
(författare)
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Torsten Gordh (1907-2010) In Memoriam
- 2010
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Ingår i: ANESTHESIOLOGY. - 0003-3022. ; 113:6, s. 1437-1438
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)
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- Ferguson, SK, et al.
(författare)
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Effects of inorganic nitrate supplementation on cardiovascular function and exercise tolerance in heart failure
- 2021
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Ingår i: Journal of applied physiology (Bethesda, Md. : 1985). - : American Physiological Society. - 1522-1601 .- 8750-7587. ; 130:4, s. 914-922
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Tidskriftsartikel (refereegranskat)abstract
- Heart failure (HF) results in a myriad of central and peripheral abnormalities that impair the ability to sustain skeletal muscle contractions and, therefore, limit tolerance to exercise. Chief among these abnormalities is the lowered maximal oxygen uptake, which is brought about by reduced cardiac output and exacerbated by O2delivery-utilization mismatch within the active skeletal muscle. Impaired nitric oxide (NO) bioavailability is considered to play a vital role in the vascular dysfunction of both reduced and preserved ejection fraction HF (HFrEF and HFpEF, respectively), leading to the pursuit of therapies aimed at restoring NO levels in these patient populations. Considering the complementary role of the nitrate-nitrite-NO pathway in the regulation of enzymatic NO signaling, this review explores the potential utility of inorganic nitrate interventions to increase NO bioavailability in the HFrEF and HFpEF patient population. Although many preclinical investigations have suggested that enhanced reduction of nitrite to NO in low Po2and pH environments may make a nitrate-based therapy especially efficacious in patients with HF, inconsistent results have been found thus far in clinical settings. This brief review provides a summary of the effectiveness (or lack thereof) of inorganic nitrate interventions on exercise tolerance in patients with HFrEF and HFpEF. Focus is also given to practical considerations and current gaps in the literature to facilitate the development of effective nitrate-based interventions to improve exercise tolerance in patients with HF.
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