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Biomedical subjects

A Ottosson

Publications and source records attributed to A Ottosson.

At least 19 recordsLinked to original sources
PubMed1999

Sutureless small bowel anastomoses: experimental study in pigs.

OBJECTIVE: To evaluate a new technique for experimental anastomosis with fibrin glue, and to compare the results with those of stapled and one-layer sutured anastomosis. DESIGN: Open laboratory study. SETTING: Teaching hospital, Sweden. ANIMALS: Ten Swedish domestic pigs. INTERVENTIONS: Each pig had three anastomoses made in the small bowel, one by each technique. The pigs were killed on the 4th postoperative day. MAIN OUTCOME MEASURES: Blood flow, collagen concentration, anastomotic index, breaking strength, thickness of bowel wall, and histological appearance. RESULTS: Two pigs died postoperatively, leaving 8 for analysis. The blood flow at each anastomotic site studied by the microsphere technique was similar irrespective of the type of anastomosis (p = 0.3), as was anastomotic collagen concentration (p = 0.09). The anastomotic index, however, was significantly higher in the stapled than in the glued or sutured ones (p = 0.03). The glued anastomosis was the weakest, being only one fifth the strength of the stapled and one third the strength of the sutured anastomosis. There was no sign of rejection of the glue (of human origin) on histological examination. Glued and stapled anastomoses showed signs of mild inflammation, which did not reach the intensity of that around the sutured anastomoses. CONCLUSION: It is possible to make a sutureless anastomosis that does not leak with a modified stapler using fibrin glue instead of staples, but the anastomosis has considerably lower breaking strength than either stapled or sutured anastomoses.

Anastomosis, Surgical↗
PubMed1997

Role of endothelium and nitric oxide in histamine-induced responses in human cranial arteries and detection of mRNA encoding H1- and H2-receptors by RT-PCR.

1. Histamine induces relaxation of human cranial arteries. Studies have revealed that the relaxant histamine H1-receptor predominates in human cerebral and the H2-receptor in temporal arteries, while H1- and H2-receptors are of equal importance in the middle meningeal artery. The purpose of the present study was to examine the role of the endothelium and nitric oxide in histamine-induced responses and to show the presence of mRNA encoding H1- and H2-receptors in human cranial arteries. 2. Electrophoresis of polymerase chain reaction (PCR) products from human cerebral, middle meningeal and temporal arteries, demonstrated products corresponding to mRNA encoding both H1- and H2-receptors in arteries with and without endothelium. The amplified PCR products were sequenced and showed 100% homology with the published sequences of these histamine receptors. 3. A sensitive in vitro system was used to study vasomotor responses to histamine. In precontracted cerebral, middle meningeal and temporal arteries with and without endothelium, histamine caused a concentration-dependent relaxation with Imax values between 87% and 81% and pIC50 values between 8.14 and 7.15. In arteries without endothelium the histamine-induced relaxation was significantly less potent (Imax values between 87% and 66% and pIC50 values between 7.01 and 6.67) than in cranial arteries with an intact endothelium. 4. This addition of histamine to arteries without endothelium and pretreated with the histamine H2-antagonist, cimetidine (10(-5) M), caused a concentration-dependent contraction of the cranial arteries with Emax values between 86% and 29% and pEC50 values between 7.53 and 6.77. This contraction was blocked by the histamine H1-receptor antagonist, mepyramine (10(-7) M), and even turned into a relaxation with Imax values between 84% and 14% and pIC50 values between 7.42 and 5.86. 5. The nitric oxide synthase inhibitor NG-nitro-L-arginine methyl ester (L-NAME, 3 x 10(-5) M) significantly inhibited the relaxant response to histamine in cerebral and temporal arteries (pIC50 values between 7.43 and 7.13). The combined treatment with L-NAME (3 x 10(-5) M) and cimetidine (10(-5) M) caused a further displacement of the concentration-response curve (pIC50 values between 7.14 and 6.57) and decreased the maximum relaxant responses in all three cranial arteries (Imax values between 62% and 39%). 6. In conclusion, this is the first study which show mRNA encoding histamine H1- and H2-receptors in human cranial arteries. The results indicate that histamine-induced relaxation of human cranial arteries is partially mediated via an endothelial H1-receptor coupled to the production of nitric oxide and partially via a H2-receptor associated with the smooth muscle cells. In addition, there is evidence for a contractile H1-receptor in the smooth muscle cells in these arteries.

Cerebral Arteries↗
PubMed1997

Release of histamine from dural mast cells by substance P and calcitonin gene-related peptide.

The aim of the present study was to examine if the neuropeptides substance P (SP), calcitonin gene-related peptide (CGRP), neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) can stimulate histamine release from mast cells in the dura mater and thereby play a role in cranial vasoregulation and local neurogenic inflammation. Dura mater mast cells were compared with peritoneal mast cells in the rat. Histamine was released from dura mater mast cells by compound 48/80, SP and CGRP but from peritoneal mast cells only by compound 48/80 and SP. NPY and VIP released quite small amounts of histamine from dural mast cells. The release of SP and CGRP from rat dura mater mast cells was blocked by the receptor antagonists FK888 and CGRP8-37 respectively, suggesting receptor mediated release mechanisms. None of the stimuli released histamine from human or porcine dural mast cells, possibly because the sampling procedure injures and incapacitates the cells.

Animals↗
PubMed1996

Contractile endothelin-B (ETB) receptors in human small bronchi.

Endothelins (ETs) are a family of novel regulatory peptides and various lines of evidence suggest an important role for ETs in regulating pulmonary function. Two receptors for endothelin, ETA and ETB, have been found in the human lung, and according to recent studies a non-ETA receptor seems to mediate the contraction of large sized human bronchi. Several studies have emphasized the importance of small bronchi in the pathogenesis of airway disease. In the present paper, improved methodology was used which enables in vitro studies of small human bronchi down to a diameter of 0.5-1.0 mm. Using the new methodology we have tried to further characterize this receptor. Small bronchi from the distal parts of the bronchial tree were obtained from pulmonary tissue removed from 15 patients with lung cancer. They were dissected and cut into ring segments, in which isometric tension was recorded. ET-1, ET-2 and ET-3 elicited strong concentration-dependent contractions of the human small bronchus. Basically, the three peptides were equipotent with about the same maximal response. Upon reapplication, they all showed the same tachyphylaxis pattern, reaching half the initial contraction. Comparative analysis of IRL 1620, a selective ETB receptor agonist, revealed that the effect of the ETB agonist was, in all respects, similar to the responses induced by the ETs. PD 145065, a combined ETA/ETB receptor antagonist competitively inhibited the contractions induced by IRL 1620, whereas FR139317, a selective ETA receptor antagonist, was without effect. In conclusion, the present study shows that accurate measurements can be made in vitro on small human bronchi and all present data are in favour of an ETB receptor mediating endothelin-induced contraction of human bronchi smaller than 1.0 mm.

Acetylcholine↗
PubMed1995

Modulation of vascular contractile responses to alpha 1- and alpha 2-adrenergic and neuropeptide Y receptor stimulation in rats with ischaemic heart failure.

In order to evaluate adaptational changes in vascular function in congestive heart failure (CHF), we studied the contractile responses of isolated arterial and venous blood vessels from rats suffering from CHF induced by coronary artery ligature, resulting in a myocardial infarction. The contractile responses of the basilar, femoral and renal arteries and of the iliac vein were examined in relation to adrenergic and neuropeptide Y (NPY) receptor function by the action of the alpha 1 agonist phenylephrine, the alpha 2 agonist clonidine and NPY. The contractile force was measured (in mN) and in % of K(+)-induced contraction as well as pD2 to each agonist. When stimulated by a 60 mM K(+)-buffer solution, the femoral and renal arteries from CHF rats responded with a stronger contraction (Emax; 9.4 +/- 0.6 and 9.8 +/- 0.6 mN) than the corresponding Sham vessels (Emax; 6.2 +/- 0.7 and 5.6 +/- 0.4 mN respectively, P < 0.001). On the contrary, the iliac vein of CHF responded less to K+ than the Sham iliac vein (Emax 2.5 +/- 0.2 and 3.7 +/- 0.5 mN, P < 0.01). The CHF iliac vein responded with a weaker contraction when stimulated with phenylephrine (Emax 1.9 +/- 0.4 mN) and showed a lower sensitivity (pD2 5.6 +/- 0.1) than the corresponding sham vessel (Emax 5.7 +/- 2.3 mN and pD2 6.3 +/- 0.5, P < 0.05). The CHF renal artery was less sensitive to clonidine (pD2 6.4 +/- 0.6) than the Sham renal artery (pD2 7.2 +/- 0.1, P < 0.05). The results indicate differences between CHF and Sham vessel segments according to both contractile capacity induced by K(+)-depolarization and to agonist induced contractile capacity and sensitivity. The differences are not of general nature but vary according to the vascular bed examined.

Animals↗
PubMed1990

Histamine receptors in brain vessels of guinea-pig: in-vitro pharmacology and ligand binding.

The subtype of histamine receptors in brain vessels of guinea-pig has been characterized by ligand binding and in-vitro pharmacology using selective antagonists. In the basilar artery histamine caused a concentration-related contraction with an EC50 of 1.6 +/- 0.3 microM. H1-receptor blockade with mepyramine and chlorpheniramine caused a displacement to the right of the histamine concentration-response curve with an apparent KD of 0.4 and 4.6 nM respectively, whereas H2-receptor blockade with cimetidine was without effect. Histamine did not induce any dilatory responses of vessels procontracted by 60 mM potassium-containing buffer in the presence or absence of histamine antagonists. Ligand-binding studies with [3H]mepyramine yielded a KD value of 5.5 nM in pial vessel membranes and 1.7 nM in the choroid plexus, confirming the presence of H1-receptors. Nimodipine caused a concentration-related blockade of histamine-induced contractions. Omission of Ca2+ from the extracellular medium for 30 min reduced the contractile responses to histamine in the basilar artery by 96%. Subsequent addition of Ca2+ caused concentration-related contractions which were inhibited by nimodipine. Thus, the histamine H1-receptor activation in guinea-pig basilar artery is coupled to dihydropyridine-sensitive Ca2+ channels.

Animals↗
PubMed1989

Pharmacological characterization of histamine receptors in the human temporal artery.

1. The subtypes of histamine-receptors which mediate dilatation of small human temporal arteries have been characterized in vitro using 'selective' agonists and antagonists. 2. Dilatory responses were studied after preconstriction with prostaglandin F2 alpha since contraction was not seen at histamine concentrations up to 10(-4) M. Histamine caused a concentration-related relaxation of cerebral vessels with an IC50 value of 2.8 +/- 0.6 X 10(-7) M. 3. Cimetidine caused a parallel shift to the right of the histamine concentration-response curve whereas mepyramine was without observable effect. This suggests the presence of histamine H2-receptors only. However, combined treatment with mepyramine and cimetidine caused a more marked displacement of the concentration-response curve to the right. Schild analysis indicated that in situations of near complete blockade of the histamine H1-receptor subtypes, simple competitive antagonism at H2-receptors can be revealed with a pA2 value of 6.58 for cimetidine. The apparent pA2 value for mepyramine was 8.58. 4. The 'selective' H1-receptor agonists pyridylethylamine, 2-methylhistamine and thiazolylethylamine, and the H2-receptor agonists dimaprit, impromidine and 4-methylhistamine all mimicked the histamine response, but all except impromidine were less potent than histamine. The order of potency was impromidine greater than thiazolylamine greater than 4-Me-histamine greater than 2-Me-histamine greater than dimaprit greater than pyridylethylamine greater than tele-Me-histamine. 5. These results indicate that the histamine-induced dilatation in small human temporal arteries is mediated by both H1- and H2-receptors and that the latter subtype of histamine receptors predominates.

Adult↗
PubMed1988

Digoxin, magnesium, and potassium levels in a forensic autopsy material of sudden death from ischemic heart disease.

In 91 cases where the cause of death was heart disease, digoxin, Mg and K concentrations in serum and ventricular myocardium were measured post mortem. Forty per cent were positive for digoxin in both serum and myocardium. The mean serum level was 5.1 +/- 2.4 nmol/l and the mean myocardial level was 42.6 +/- 27.5 ng/g. Correlation could be established between serum and myocardial concentrations of digoxin. There were statistically significant differences in serum as well as in myocardial digoxin levels in persons on 0.13 mg and 0.25 mg per day, respectively. Myocardial levels of Mg and K were low as generally found in persons with ischemic heart disease. There was no correlation between these levels and myocardial digoxin concentrations. Caution must be exercised in the assessment of digoxin results from cadaver samples because of the postmortem rise of digoxin serum concentrations. Considering this fact, the results still indicate that the prevalence of toxic digoxin concentrations might be more common than previously thought.

Adult↗
PubMed1988

Enhanced vasoconstrictor responses to potassium, 5-hydroxytryptamine, and prostaglandin F2 alpha of isolated coronary arteries from magnesium-deficient rats. Comparison with vasomotor activity of aorta.

Wistar rats were fed a low magnesium diet for 8 or 12 weeks, resulting in reduced levels of magnesium in plasma, heart, and skeletal muscle, as compared with pair-fed control rats. The magnesium-deficient rats also had reduced tissue levels of potassium. Coronary arteries and thoracic aorta from magnesium-deficient rats and control rats were incubated in tissue baths and the contractile responses to potassium, 5-hydroxy-tryptamine, and prostaglandin F2 alpha were investigated using a sensitive in vitro system. The concentration-contraction curve, for all agents was shifted to the left in coronary arteries from magnesium-deficient rats. In aorta from magnesium-deficient rats, the pattern of change in reactivity to these agonists was not uniform: the concentration-contraction curve for 5-hydroxytryptamine was shifted to the left, the contractile response to prostaglandin F2 alpha was reduced, while there was no change in the response to potassium. The contractile response to the administration of calcium to calcium-depleted, potassium-depolarized vessels from magnesium-deficient rats was enhanced; the effect was more pronounced in coronary arteries as compared to the aorta. Hence, the vasomotor reactivity of coronary arteries appears to be more sensitive than is the aorta during magnesium-deficient conditions.

Animals↗
PubMed1988

Characterization of histamine receptors in isolated human cerebral arteries.

1. The subtypes of histamine-receptors which mediate dilatation of small human cerebral arteries have been characterized in vitro using 'selective' agonists and antagonists. 2. Dilator responses were studied after preconstriction with prostaglandin F2 alpha, since contraction was not seen with histamine concentrations up to 10(-4) M. Histamine caused a concentration-related relaxation of cerebral vessels with an IC50 value of 5.2 +/- 1.6 x 10(-8) M. 3. Mepyramine caused a parallel shift to the right of the histamine concentration-response curve whereas cimetidine was without observable effect. This suggests the presence of histamine H1-receptors only. However, combined treatment with mepyramine and cimetidine caused a more marked displacement of the concentration-response curve to the right. Schild analysis indicated that in situations of near complete blockade of either of the histamine receptor subtypes, simple competitive antagonism both at H1- and H2-receptors can be revealed with a pA2 value of 8.64 for mepyramine and a pA2 value of 6.52 for cimetidine. 4. The 'selective' H1-receptor agonists pyridylethylamine, 2-methylhistamine (2-Me-histamine) and thiazolylethylamine, and the H2-receptor agonists dimaprit, impromidine and 4-methylhistamine (4-Me-histamine) all mimicked the histamine response, but were less potent than histamine. The order of potency was thiazolylethylamine greater than dimaprit greater than impromidine greater than 2-Me-histamine greater than pyridylethylamine greater than 4-Me-histamine. 5. These results indicate that the histamine-induced dilatation in small human cerebral arteries is mediated by both H1- and H2-receptors and that the former subtype of histamine receptor predominates.

Adult↗
PubMed1987

Peptide-containing nerve fibers in human cerebral arteries: immunocytochemistry, radioimmunoassay, and in vitro pharmacology.

Nerve fibers containing neuropeptide Y, vasoactive intestinal peptide (VIP), substance P (SP), and calcitonin gene-related peptide (CGRP) were seen in the adventitia or at the adventitia-media border of human cerebral arteries obtained during neurosurgical procedures. Radioimmunoassay of human cerebral arteries, removed at autopsy, revealed that the levels of the four peptides did not differ among the major cerebral arteries. There was, however, a gradual decline in peptide concentrations with increasing age of the patients, as measured in the proximal part of the middle cerebral artery. Pharmacological experiments on fresh segments of cerebral (pial) arteries in vitro revealed that neuropeptide Y caused vasoconstriction per se but did not potentiate the contractile response of noradrenaline. VIP, peptide histidine methionine-27 (PHM-27), SP, neurokinin A (NKA), and human CGRP potently relaxed vessels precontracted by prostaglandin F2 alpha, the relative potency being human CGRP greater than SP greater than VIP greater than NKA greater than PHM-27. The amount of relaxation varied between 55% (SP) and 96% (human CGRP) of the prostaglandin F2 alpha-induced contraction. The peptide effects were not antagonized by propranolol, atropine, or cimetidine, suggesting an action that does not involve adrenergic, cholinergic, or histaminergic receptors.

Age Factors↗
PubMed1986

Vasomotor responses of isolated human coronary arteries to magnesium, nitroglycerin and verapamil: a comparison with coronary arteries from cat and rat.

The vasomotor responses in vitro to magnesium, nitroglycerin and verapamil were investigated in human coronary arteries. In order to examine possible species differences in reactivity to these agents, experiments were performed also on cat and rat coronary arteries. Potassium (124 mM) regularly produced stable contractions suitable for experiments with dilator agents. The order of potency for eliciting relaxation was the same in all three species; verapamil greater than nitroglycerin greater than magnesium. Maximum relaxation induced by nitroglycerin or magnesium was significantly lower in arteries from cat as compared to that obtained in coronary artery segments from man and rat. Spontaneous rhytmic activity was often present in human coronary arteries but never in arterial segments from cat or rat. The rhytmic activity was frequently enhanced by the addition of prostaglandin F2 alpha (3 microM) to the tissue bath, on the other hand the rhythmic activity was depressed, or even abolished, by potassium (124 mM), magnesium (1.2-13.2 mM), nitroglycerin (2.2 X 10(-5) M) or verapamil (10(-8)-10(-7) M). The magnitude of the vasomotor response of feline coronary arteries to nitroglycerin or verapamil was dependent on the extracellular concentration of magnesium; in the presence of a high concentration of magnesium (4.4 mM) the dilator effect of nitroglycerin was enhanced while that of verapamil was slightly depressed. The dilator activity of the two agents was not changed by incubation of the vessel segments in a magnesium-free medium as compared to that obtained in the standard (1.2 mM Mg) buffer solution.

Adult↗
PubMed1986

Demonstration of perivascular peptides and changes in concentration with age in man.

By immunocytochemistry, human cerebral arteries have been found to be invested by perivascular fibres which contain neuropeptide Y, substance P and vasoactive intestinal polypeptide (VIP). The concentrations of the peptides are comparable for substance P and VIP, whereas that of neuropeptide Y is much higher. A marked reduction in radioimmunoassayable peptide levels was observed with advancing age of the patients.

Adolescent↗
PubMed1985

Aspiration and obstructed airways as the cause of death in 158 consecutive traffic fatalities.

In order to assess the number of road deaths caused by aspiration, 158 consecutive traffic fatalities were retrospectively analyzed. Approximately 20% of the victims dead at the scene or within 24 hours after the accident had any significant amount of blood in the airways. However, this aspiration did not alter the final fatal outcome, as all victims except one had virtually unsurvivable injuries. We conclude that aspiration is very rare as the cause of death among traffic fatalities.

Accidents, Traffic↗
PubMed1984

Traffic fatalities in a system with decentralized trauma care. A study with special reference to potentially salvageable casualties.

P6 evaluate a system with decentralized trauma care, a review was made of all 158 traffic fatalities in 1981 in the southern part of Sweden. The region has 15 well-equipped and well-staffed small- and medium-sized hospitals and two university hospitals with extensive resources. The patients are usually brought by ambulance to the closest receiving facility. Only three persons could possibly have been saved--one suffering from a lacerated femoral artery and two patients in whose cases missed diagnoses (eg, bowel rupture or cardiac tamponade) might have contributed to the fatal outcome. The present investigation reveals that high survival rates after traffic trauma can be achieved with a conventional Swedish trauma care system.

Accidents, Traffic↗
PubMed1981

Late aortic rupture after lye ingestion.

A case of liquid lye ingestion with late aortic rupture is reported. The rupture occurred 44 days after the lye ingestion. This case report shows that the lye induced tissue damage has a long duration and may lead to late aortic rupture, especially if there is an additional trauma to the esophagus due to dilatation and perforation of the esophageal wall.

Adolescent↗