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Biomedical subjects

G Nylander

Publications and source records attributed to G Nylander.

At least 109 records · Page 6Linked to original sources
PubMed1982

Induced hyperosmolality effects on extracellular fluid volume, lymph flow and osmolar equilibrium: studies in the rat.

The effects of experimentally induced hyperosmolality has been studied in rats. Renal vascular pedicle ligation was performed on all animals to prevent renal clearance of the infused solute, xylose, and allow accurate ECF space determinations with 51Cr EDTA. Small volume hyperosmolar xylose infusions caused parallel elevation of the osmolality of thoracic duct lymph and arterial plasma. A positive correlation was obtained between lymph osmolality and flow alterations. The maximal osmolality elevation of 22 mosm X kg-1 H2O was associated with an intracellular fluid mobilisation which was equal to 7.1% of the ECF space. The infused and mobilised fluid volumes were distributed unequally between the intra and extra vascular compartments of the ECF.

Animals↗
PubMed1982

51Cr EDTA determinations of the extracellular fluid volume in hemorrhage: a study with fed and starved rats.

Extracellular fluid volumes have been determined in fed and 24-30 h starved rats, before and after 60 min of hemorrhagic hypotension at 70 mmHg. Bilateral renal vascular ligation was carried out to prevent clearance of the isotope tracer used, 51Cr EDTA. The time taken for a bolus of the tracer to distribute itself in its space, was determined in fed and starved animals after the standard period of hypotension. This was found to be 37 min for fed animals, and 50 min for those which had been starved. When the isotope ECF space was compared before and after hemorrhage in fed animals, it was unchanged, despite an estimated blood volume loss of 39%. The isotope ECF space was reduced 5.5% after hemorrhage in animals which had been starved. It is concluded that fed rats mobilised intracellular fluid to the interstitium in hemorrhage, whereas, starved animals did not. This finding of variable fluid homeostasis is ascribed to the different nutritional status of the animals investigated, and has considerable implications.

Animals↗
PubMed1982

Glucose, insulin and osmolality changes in rats sustaining different hemorrhage volumes.

Plasma glucose, osmolality and insulin have been investigated during hemorrhage in non-starved rats. The rate of blood loss leading to hemorrhages of 44% and 55% of the estimated original blood volume determined the patterns of response. Substantial hyperglycemic hyperosmolality and insulin values appropriate for the raised levels of glucose were observed in the animals bleeding more rapidly. The slower rate of hemorrhage was associated with only moderate hyperglycemia and hyperosmolality, while the insulin values rose to very high levels, 45 times basal. It is postulated that altered glucose-insulin metabolism in haemorrhage may have important consequences for fluid homeostasis, and the rate of bleeding is the fundamental factor steering this effect.

Animals↗
PubMed1982

Dysfunction of the cricopharyngeal muscle. A cineradiographic study of patients with dysphagia.

Of 250 consecutive patients with dysphagia studies by cineradiography, 55 (22%) had dysfunction of the cricopharyngeal muscle, indicated by an indentation of the pharyngo-esophageal junction during swallowing. The indentation measured less than 25% of the esophageal diameter in 29 patients, less than 50% in 18, and greater than 50% in 8 and was transient in 36 patients and continuous in 19. In 35 patients, abnormalities of swallowing were seen, including pharyngeal constrictor paresis [8], epiglottic dysfunction [17], misdirected swallowing [23], and esophageal webs [19]. Cineradiography during swallowing is important in the diagnosis, since dysfunction is often overlooked on a routine examination.

Adult↗
PubMed1982

Inhibition of pentagastrin-stimulated gastric acid secretion by upper intestinal hyperosmolality in chronic gastric fistula rats.

The effects of upper small intestinal perfusion with iso-osmolar or hyperosmolar polyethylene glycol (PEG) solutions on maximal gastric acid secretion stimulated by intravenous pentagastrin was investigated in Sprague-Dawley rats. The animals were provided with a chronic gastric fistula, a gastroenterostomy and a 4-cm duodenal loop anastomosed end-to-side to the jejunum. The oral end of the duodenal loop was closed and intubated for infusion of various solutions. Saline was infused in the control experiments, 2 ml h-1. In the test experiments, saline was replaced with PEG, 300, 900 or 1,200 mosm.kg-1. Duodenal perfusion with iso-osmolar PEG, 300 mosm-kg-1, did not alter maximal acid secretion. Duodenal perfusion with hyperosmolar PEG 900 or 1,200 mosm.kg-1 significantly inhibited the stimulated 2-hour acid output by 47 and 48% respectively (p less than 0.01). Indomethacin, an inhibitor of the prostaglandin synthesis, did not alter the stimulated acid secretion, and the inhibitory influence on acid secretion of duodenal perfusion with PEG 1,200 mosm.kg-1 as not affected by the drug.

Animals↗
PubMed1982

Cineradiography of the pharyngeal stage of deglutition in 150 individuals without dysphagia.

With the aid of cineradiography the pharyngeal stage of deglutition was examined at a speed of 50 and 100 frames per second among 150 individuals without dysphagia. In 124 (83%) the act of swallowing had a symmetrical and synchronous pattern. Different types of aberrations from this pattern were registered in 26 individuals (17%). In seven individuals the epiglottis did not tilt down properly but remained in a transverse position during deglutition. In eight individuals, contrast medium passed into the laryngeal vestibule. Seven individuals had a dysfunction of the cricopharyngeal muscle which did not relax properly. One individual had a web in the upper oesophagus. In all but two individuals the aberrations were isolated and not concomitant with other abnormalities of the act of swallowing.

Adult↗
PubMed1982

Cineradiography of the pharyngeal stage of deglutition in 250 patients with dysphagia.

In order to define the diagnostic outcome of cineradiographic examination of the swallowing act (pharyngeal stage) in patients with dysphagia, 250 such patients were consecutively examined at filmspeeds of 50 and 100 frames per second. Synchronous and symmetrical swallowing was observed in 20% of the patients while 80% exhibited functional abnormalities i.e., epiglottic dysfunction (33%), misdirected swallowing and aspiration (41%), cricopharyngeal dysfunction (22%), paresis of the pharyngeal constrictor musculature (10%), webs (15%) and Zenker diverticula (2%). These results clearly indicate that cineradiography can frequently disclose functional abnormalities in the act of swallowing among patients with dysphagia and explain the symptoms of these patients. Cineradiography is clearly superior to conventional single-film technique in revealing functional abnormalities in the act of swallowing.

Adolescent↗
PubMed1982

Surgical resection of the rat colon: effects on carcinogenesis by 1,2-dimethylhydrazine.

Following a 3-month treatment with 1,2-dimethylhydrazine (DMH) given weekly (sc), outbred Sprague-Dawley rats were subjected to partial resection of the transverse colon. After surgery, DMH treatment was continued for 6 months, after which the rats were killed. At autopsy, 63% of the tumors were found in the transverse colon. By contrast, only 29% of the tumors found in the "sham-operated" control animals occurred in the transverse colon. Surgical trauma in the colon mucosa subjected to the action of carcinogenic agents appeared to promote the conditions suitable for the development of tumors in that organ.

Animals↗
PubMed1982

Osmolar changes in haemorrhage: the effects of an altered nutritional status.

Fed and 24-30 hour starved rats were submitted to haemorrhagic hypotension, 70 mmHg, with a modified Wigger's system. Neuroleptanalgesia was used to ensure a normal degree of stress reactivity. Despite fed animals losing 53% of their original blood volume (BV) and starved animals 47% (BV = 6% prestarved body weight), blood gas data and creatinine levels confirmed a well intact and compensated status in both groups. Fed animals compensated for the greater haemorrhage with a haematocrit reduction which was double that in starved animals. When the alterations in osmole skeletons were compared, evidence for an intracellular fluid (ICF) shift to the interstitium was obtained in fed rats. Their NaCl space increased by 5.5%. Glucose increased its osmolar effect by 224% among fed animals and was reduced in those which had been starved. Glucose was identified as the solute causing an acute mobilisation of ICF to the interstitium.

Animals↗
PubMed1981

Further studies on the carcinogenesis of the colon of the rat with special reference to the absence of intestinal contents.

The proximal and distal ends of the ascending, transverse and descending colon of 67 Sprague-Dawley rats were severed and stitched to the abdominal wall. The remaining colon was anastomosed end to end. The disarticulated colon loop was rinsed 30 times over 15 days to remove all traces of intestinal contents. The animals were then given subcutaneous injections of 1,2-dimethylhydrazine (21 mg/kg body weight) for 27 weeks. During that period, the isolated loops were rinsed with saline once a week. The rats were killed after seven months of treatment. Eighty-five tumors developed in the 67 animals: 20 in the isolated loops and 65 in the end-to-end anastomosed colon. The carcinogen employed reached the colonic loop through the circulation and induced (independently of bile acids) mucosal changes that led to the development of colonic tumors.

1,2-Dimethylhydrazine↗
PubMed1981

Posthemorrhagic changes in plasma water and extracellular fluid volumes in the rat.

Anesthetized rats were submitted to a standardized hemorrhage to 40 mm Hg by withdrawing 35 to 40% of the total blood volume. The plasma water and the extracellular fluid volumes of the whole animal and selected tissues were estimated with 125 I human serum albumin and 51Cr EDTA, respectively, after recovery periods of 10 and 90 minutes. The plasma water volume of the whole animal decreased, but approximately 50% of the shed plasma water was restored within 10 minutes after the hemorrhage. The extracellular fluid volume of the whole animal did not change significantly after hemorrhage, whereas this fluid compartment was regionally reduced in the liver, spleen, and subcutaneous fat after a 10-min recovery period but only in the liver after a 90-min recovery period.

Animals↗
PubMed1981

Comparison of the dose-response curves for acid output to pentagastrin determined by two techniques in chronic gastric fistula rats.

The dose-response (DR) curves for acid output to intravenous pentagastrin were determined by two techniques in conscious rats with chronic gastric fistula. With the continuous DR technique, the dose of pentagastrin was doubled each hour; with the single DR technique, one dose of pentagastrin was infused for 5 h on each test day. The acid response to all doses but the lowest were higher with the single DR than the continuous DR technique, but the dose required to produce half the maximal response did not differ with the two techniques. Similar results were obtained when the DR curves were analyzed by application of the Michaelis-Menten equation. Accordingly, in conscious rats with gastric fistulas, the single DR technique gives a higher figure for the secretory capacity of the parietal cells than the continuous DR technique, but the two techniques give the same estimation of the sensitivity of the parietal cells.

Animals↗
PubMed1981

Thrombosis after elective phlebography as demonstrated with the 125 I-fibrinogen test.

The 125I fibrinogen test was used in 54 patients before and daily for 4 to 6 days after phlebography, for evaluating the incidence of post-phlebographic thrombosis. The indication for phlebography was in all cases varicose veins with perforators. A significantly increased fibrinogen uptake was found after phlebography in 4/54 patients in the calf, suggesting development of deep venous thrombosis, which, however, could not be confirmed with plethysmography or thermography. None had clinical signs of deep vein thrombosis. The rather low incidence of post-phlebographic thrombosis compared with other series is discussed.

Adult↗
PubMed1981

Effects of intestinal obstruction of plasma water and extracellular fluid volumes in the rat.

Total and regional plasma water and extracellular fluid volumes were measured in rats after obstruction of the small intestine. The rats lost 12.6 per cent of their initial weight. The volume of the sequestrated fluid in the obstructed intestine corresponded to 91 per cent of the plasma water volume. Intestinal obstruction caused a 19 per cent reduction of the total plasma water volume, while the total extracellular fluid volume was unchanged. Regional extracellular fluid volumes were diminished in the lung, liver and gastric antrum and increased in omental fat. The results indicate regional differences in fluid space responses to obstruction of the small intestine.

Animals↗
PubMed1980

Plasma water and 51Cr EDTA equilibration volumes of different tissues in the rat.

The EDTA space and the plasma water volume of the whole animal and selected tissues were investigated with constant EDTA infusions of different duration in the rat. The calculated EDTA space increased with the duration of the infusion both in the whole animal and the tissues sampled. The plasma water volume remained constant, and therefore the calculated increase of the EDTA space suggests a slow intracellular accumulation of the tracer. As intracellular accumulation of EDTA increases with experimental time, it is necessary to use as short an experimental interval as possible to reduce this error when determining extracellular fluid volumes.

Animals↗