Endotoxin inactivation in plasma from patients with gram-negative infection--an in vitro study.
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Bacterial Infections↗
Biomedical subjects
G Nylander
Publications and source records attributed to G Nylander.
The effect of hemorrhagic stress on liver gluconeogenesis. An isolated rat liver perfusion study with three-carbon units as substrates.
This effect of hypovolemic stress on hepatic gluconeogenesis has been studied using isolated perfused organs obtained from starved rats subjected to 60 min hemorrhagic hypotension at 70 mmHg. Four different substrates were used: lactate, pyruvate, glycerol and alanine. The substrates were added without any stress endocrine stimulation in the perfusate. Using a recirculating system and supraoptimal substrate availability, a significant higher rate of gluconeogenesis was confirmed for the stressed donor livers: glycerol (+100%), alanine (+97%), lactate (+64%) and pyruvate (+62%). Glucose accumulation was linear for all control and experimental groups. In the absence of added stress hormones, known to stimulate gluconeogenesis, the findings are concordant with an in vivo hormone activation of key enzymes in the gluconeogenic pathway, persisting for the 60 min duration of the in vitro perfusion.
Alanine↗
Monitoring the histogenesis of colonic tumors in the Sprague-Dawley rat.
A total of 306 male Sprague-Dawley rats, injected with dimethylhydrazine (DMH), dose 21 mg/kg body weight s.c., were investigated. Of the 109 rats receiving the dose once only, seven colonic adenocarcinomas developed; all seven (100%) were seen to originate in discrete lymphoid patches. Of the 97 rats treated with one dose/week for 3 months, only 6% of the 50 adenocarcinomas developed in discrete lymphoid patches, while 46% were seen to originate in a pre-existing adenoma. Of the remaining 100 rats, receiving one dose/week for 6 months, only 3.5% of the 57 adenocarcinomas arose from discrete lymphoid patches; 43.9% arose from a pre-existing adenoma. Thus, the histogenesis of adenocarcinomas at our laboratory appears to be dose-dependent. Experiments are therefore being designed to monitor in detail the events of these two histogenetically different adenocarcinomas in the colonic mucosa in our animal model.
1,2-Dimethylhydrazine↗
Endotoxin inactivation in plasma from septic patients: an in vitro study.
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Adolescent↗
Endotoxin: routes of transport in experimental peritonitis.
A quantitative endotoxin assay was applied in this study of endotoxin transport from the infected abdomen. In rats with fecal peritonitis, extremely high concentrations were found in thoracic duct lymph (approximately 400 times higher than those found in arterial and portal vein plasma). Taking flow rates into account, the thoracic duct carries 34 ng/hour and the protal vein 49 ng/hour after 2 hours of peritonitis. Endotoxin quantities transported by the portal vein never exceed the proposed endotoxin filtrating capacity of the liver. Furthermore, the onset of systemic endotoxemia parallels the appearance of endotoxin in the thoracic duct. The hypothesis put forward is that the development of systemic endotoxemia is mainly mediated by lymphatic transport. The results also indicate that endotoxin is normally absorbed from the intestine and transported by portal blood.
Animals↗
Effects of intraluminal hydrostatic pressure on L-methionine absorption in the obstructed small intestine of the rat.
The effects of elevated intraluminal hydrostatic pressure on the active absorption of the amino acid selenium 75 L-methionine has been analyzed in the normal and obstructed small intestine. An intestinal loop of defined position and length was included in a recircling perfusion system from which the elimination rate of the radiolabeled amino acid was measured. Preset pressure levels within the system were maintained by a servo-controlled unit, which added or subtracted volume to keep the pressure constant. The rate of amino acid elimination increased when the nonobstructed loop was subjected to a pressure of 10 cm H2O but decreased when exposed to 20cm H2O. Using a loop of intestine subjected to 48 hours of obstruction, amino acid elimination was greatly retarded compared with that of the nonobstructed loop. By increasing the intraluminal pressure to 10 and 20 cm H2O, the elimination rate increased, equalling that of the nonobstructed gut. The results suggest that intestinal obstruction per se decreases active absorption secondary to impaired intestinal viability. Moderately increased intraluminal pressure adds a driving force to L-methionine absorption, the mechanism of which is obscure.
Animals↗
Nutritional status and endocrine response to hemorrhage.
Hyperglycemia-inducing hyperosmolality has recently been proven beneficial in the maintenance of blood volume and extracellular fluid volume during early hemorrhagic hypotension. Fed animals benefitted from better plasma refill compared with starved ones when subjected to equal blood loss. Using lightly sedated fed and 24-30 h starved rats, hormones with relevance to glucose homeostasis were studied during 90 min of hemorrhagic hypotension of 70 mmHg (1 mmHg = 133.32 Pa). Marked differences in the overall hormonal developments were found between the two groups. In fed rats, insulin and glucagon responses were initially attenuated, while somatostatin increased to an early peak level at 30 min, returning to basal at 90 min. In starved rats, somatostatin increased gradually during the 90 min. Adrenaline release was massive in both groups. Corticosterone showed no increase from basal levels in the fed group during hemorrhage, while starved rats increased their basal level fourfold already at 30 min. These data are presented as evidence that changing nutritional status alters hormonal response to hypovolemic stress.
Animals↗
Gastric emptying and intestinal transit of hyperosmolar solutions in relation to indomethacin and certain gut polypeptides in the rat.
The present study in the rat demonstrates an inhibitory mechanism of gastric emptying, sensitive to the osmolality of a liquid meal. Gastric emptying and intestinal transit were studied in groups that differed with regard to the osmolality of the gastric or duodenal instillation, experimental time, and indomethacin treatment. By intragastric instillation animals were fed an aqueous solution containing the nonabsorbable marker 51CrO2-4. After certain fixed time intervals the rats were killed and the stomach and small intestine were dissected out en bloc. The distribution of the isotope along the gastrointestinal canal was then determined. Intestinal transit was evaluated in a similar manner. The marker solution was introduced into the duodenum. A hyperosmolar solution, 1200 mOsm kg-1, was emptied from the stomach significantly more slowly than was an iso-osmolar solution, 300 mOsm kg-1. Of the iso- and hyper-osmolar solutions 87% and 74%, respectively, were emptied in 1 h. The isotope distribution along the intestinal canal after intraduodenal instillation was not affected by the osmolality of the installation. The osmotic inhibition of gastric emptying was not affected by indomethacin treatment (4 mg kg-1) or related to elevated plasma levels of gastrin, neurotensin, somatostatin, or gastric inhibitory polypeptide.
Animals↗
Tissue ischemia and hyperbaric oxygen treatment: an experimental study.
The results of the present experiments showed that The general post-burn edema in a scald burn model was reduced with HBO treatment and the water content in the contralateral unburned mouse ear did not statistically significantly differ from that of uninjured untreated animals. In post-ischemic skeletal muscle there was an increased water content from 5 hours to 48 hours after tourniquet ischemia of 3 hours duration. HBO treatment reduced the edema and the reduction persisted for 40 hours after the last treatment. The stores of high energy phosphate compounds were depleted after 3 hours of skeletal muscle ischemia. Repeated HBO treatments resulted in increased levels of ATP and PCr and decreased lactate levels. Reduction of phosporylase activity, a sensitive marker for muscle cell damage, is to a great extent prevented by HBO treatment in the post-ischemic phase.
Animals↗
Mechanical compliance of the small intestine related to long-standing obstruction. An experimental study in rats.
Mechanical compliance was studied in rat small intestine subjected to 48 hours of simple obstruction. The values were compared with those obtained in a corresponding section of normal gut. A closed system was used, constructed for continuous measurement of volume-pressure relationships within a hollow organ. The pressure-raising velocity was regulated by programming a steering unit connected to the system. The findings accorded with the hypothesis of an increase in compliance of the obstructed small intestine. The experiments further demonstrated that repeated artificial increases in intraluminal pressure cause change in intestinal compliance.
Animals↗
Minimal invasive carcinoma of the colon in rats.
The careful histologic examination of the macroscopically normal colon in rats treated 8 months previously with a single dose of the colonotropic carcinogen dimethylhydrazine (DMH) demonstrated atypical colonic glands in normally occurring lymphoid mucosal patches. The atypical glands were characterized by the absence of cytoplasmic mucus, hyperchromatic cell nuclei, cell stratification, and increased number of mitotic figures. In 61.7% of the experimental animals, atypical colonic glands were found beyond the boundary of the muscularis mucosae, but in none of the controls. Thus, microinvasive adenocarcinoma of the colon seems to be a common finding in rats treated with a single dose of DMH. These adenocarcinomas remain, however, undetected at macroscopic examination. Measurements performed in consecutive lymphoid aggregates demonstrated that 50% of rats receiving DMH had thicker lymphoid aggregates than control animals. In spite of this, no tumor was recorded at naked eye examination in these areas. The macroscopic examination appears to be an unreliable method of ruling out malignancy in experimental rats treated with a single dose of the above-mentioned carcinogen.
Adenocarcinoma↗
[Replantation surgery should take care of patients with severe traumatic amputations of the upper extremities].
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Adult↗
Double-contrast examination of the pharynx.
The radiographic techniques for evaluation of the pharynx are described, with particular emphasis on double-contrast examination. Radiographic anatomy of the pharynx is illustrated.
Barium Sulfate↗
Reduction of postischemic edema with hyperbaric oxygen.
In recent years, reports have shown positive effects of hyperbaric oxygen (HBO) treatment in posttraumatic circulatory insufficiency of the extremities. A tourniquet model for temporary ischemia was used to examine such treatment in rats. The circulation of the rat hindlimb was interrupted for 3 hours, while the contralateral uninjured leg served as control. There was a significant (p less than 0.001) postischemic edema in the tourniquet leg up to 48 hours after restoration of circulation. One group of animals received treatment with hyperbaric oxygen at 2.5 atmospheres absolute (ATA) for 45 minutes after release of the tourniquet. This significantly reduced (p less than 0.001) the postischemic edema, and the reduction persisted for 40 hours after the last treatment. It is concluded that hyperbaric oxygen reduces postischemic edema. Hyperbaric oxygen may therefore be useful as an adjuvant in the treatment of acute ischemic conditions when surgical repair alone fails or is not sufficient to reverse the ischemic process.
Animals↗
Defecography.
Defecography is a technique of examining the rectum and anal canal in which the patient is studied while sitting down rather than recumbent and recordings are obtained both at rest and during straining. The authors describe their findings in 83 patients with dyschezia. Defecation was normal in 28 patients. Prolapse of the anal mucosa was seen in 13 patients and internal procidentia in 23, 12 of whom also had intussusception manifested as rectal prolapse. A deep rectogenital fossa associated with an enterocele was seen in 16 patients; 13 had a proctocele, while fecal retention was seen in 5. Descent of the pelvic floor and changes in the angle between the rectum and anal canal were assessed. The authors recommend defecography as a more physiological means of assessing rectal dysfunction.
Adult↗
Acid and hyperosmolal solutions in the upper intestine of chronic gastric fistula rats inhibit gastric acid secretion by different mechanisms.
In chronic gastric fistula rats 0.20 M HCl and 1200 mOsm X kg-1 solution of polyethylene glycol (PEG) infused into a duodenal loop anastomosed to the jejunum (Roux-en-Y) produced maximal inhibition of pentagastrin-stimulated acid secretion, which amounted to 60% and 50%, respectively. In the present study in Roux-en-Y rats with gastric fistula, perfusion of the loop with hyperosmolal (1200 mOsm X kg-1 of PEG solution) 0.20 M HCl produced a greater reduction of the maximal response to pentagastrin (91% inhibition) than perfusion with 0.20 M HCl (64%), suggesting that HCl and hyperosmolal solution inhibit secretion by different mechanisms. The maximal acid response to histamine was more resistant to inhibition than that to pentagastrin; 0.20 M HCl inhibited secretion by 43%, 1200 mOsm X kg-1 of PEG solution by 42%, and hyperosmolal 0.20 M HCl by 60%. The results suggest that HCl and hyperosmolal solution also inhibit histamine-stimulated secretion by different mechanisms. The anatomical sites of the mechanisms remain to be established.
Animals↗
Correlation between peptide YY-induced myoelectric activity and transit of small-intestinal contents in rats.
The effect of peptide YY (PYY) on the myoelectric activity of the small intestine was studied in relation to the transit of a 51Cr marker solution in fasted conscious rats. The myoelectric activity was recorded by means of bipolar electrodes implanted at 5, 20, and 35 cm from the pylorus. The marker was administered in the duodenum immediately after an activity front of a migrating myoelectric complex (MMC) had passed the first recording site. Under control conditions, the propagation of one activity front over the three recording levels was accompanied by the propulsion of 90.2 +/- 11.4% of the total radioactivity as one portion distal to the third electrode site. The median peak of the radioactivity was recovered at a distance approximately twice that propagated by an activity front. Intravenous infusion of PYY (50 pmol X kg-1 X min-1) had no effect on the occurrence of the MMC in the duodenum but interrupted its distal propagation and almost totally abolished the spiking activity in the jejunum. In comparison with controls, the transport of the marker was significantly retarded, and the median peak of the radioactivity was recovered proximal to the third electrode site. The results indicate that the small-intestinal contents are propelled as one portion in front of a propagating activity front. The inhibition of the activity front by PYY may account for the delay in the transit of the small-intestinal contents.(ABSTRACT TRUNCATED AT 250 WORDS)
Action Potentials↗
Endotoxin-transport routes and kinetics in intestinal ischemia.
A rat model representing segmental intestinal ischemia was used to study the absorption and transport of endotoxin from the ischemic gut. Serial quantitative analyses were made on peritoneal fluid, thoracic duct lymph and arterial and portal vein blood. Significantly increased endotoxin concentrations were found in thoracic duct lymph before transmural leakage took place. After leaking through the devitalized intestinal wall, endotoxin was transported by both lymphatic and portal routes. Kinetic analysis revealed that systemic endotoxemia paralleled the appearance of endotoxins in thoracic duct lymph, preceding a significant increase in the portal vein. The amount transported by the portal vein never exceeded the proposed endotoxin-filtrating capacity of the liver. In intestinal ischemia, consequently, systemic endotoxemia appears to be mediated mainly by lymphatic transport.
Animals↗