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Biomedical subjects

O Eriksson

Publications and source records attributed to O Eriksson.

At least 145 records · Page 8Linked to original sources

Endotoxins in cardiopulmonary bypass.

Endotoxins are biologically active substances derived from the cell wall of degraded gram-negative bacteria. Since sterile water may also contain large amounts of endotoxins, these are easily introduced into the manufacturing processes of technical medical material, such as the extracorporeal components used in cardiopulmonary bypass. In hemodialysis, the presence of endotoxins has been related to untoward effects in patients. Using the limulus amebocyte lysate test, we determined the serum concentration of endotoxin in 42 patients undergoing coronary bypass operations. The values increased during cardiopulmonary bypass, exceeding the normal range of 0 to 20 ng/L in 10 patients with a maximum of 82 ng/L, which probably indicates endotoxin release from the extracorporeal equipment. We found no obvious relation to postoperative morbidity. The endotoxin levels of this study are considerably lower than those reported in two other studies of patients having cardiopulmonary bypass. This might be due to less intraoperative contamination but possibly also to differences in analytic methods.

Adult↗

Radiocesium uptake in reindeer on natural pasture.

In an experiment initiated after the Chernobyl accident, a herd of reindeer was followed before and after a temporary move from a highly contaminated area (greater than 20 kBq 137 Cs/m2) to a less contaminated area (less than 3 kBq 137Cs/m2) of natural pasture. The animals grazed in a highly contaminated area until they were moved to the low contaminated area where they grazed from late November to late April. The level of 137Cs in meat was about 12 kBq/kg at the time when the animals were moved (Nov.) to the low contaminated area and it decreased to about 3 kBq/kg with an effective half-time of about 1 month, after the animals were moved. In the low contaminated area the fractional transfer, fm, of 137Cs was determined to be 0.65 d/kg during winter pasture, mainly on lichens, and 0.30 d/kg during summer pasture, in the fields. The actual intake of radiocesium was determined by measurement of ruminal samples from slaughtered animals. The maximal radiation dose to reindeer in Sweden after the Chernobyl accident was estimated to less than 200 mSv/a with a dose rate of less than 1mSv/d during the winter period of maximum tissue concentration of radiocesium.

Accidents↗

Vaginal administration of low-dose oestradiol--effects on the endometrium and vaginal cytology.

Twenty (20) post-menopausal women, mean age 62.4 yr, presenting with symptoms associated with urogenital atrophy were treated intravaginally with daily doses of 25 and 50 micrograms oestradiol (E2) in a double-blind, cross-over study. After randomization, the patients started daily treatment with pessaries containing either 25 or 50 micrograms E2 for 3 wk, followed by a maintenance period of 6 wk during which the pessaries were used only twice a week. A 4-wk wash-out period was followed by another treatment period of 9 wk. The effects on the karyopyknotic index (KPI) and on endometrial histopathology were assessed before and after 3, 9, 16 and 22 wk of treatment. In the case of the 25 micrograms dose the mean KPI values were 34.7 and 20.9% after 3 and 9 weeks of treatment, respectively, the corresponding figures after treatment with 50 micrograms E2 being 39.2 and 22.7%. No dose-effect relationship was apparent from the vaginal cytology findings. Endometrial biopsies could not be taken systematically in all patients. Weak proliferation of the endometrium was observed in 1 woman after 3 wk of daily treatment with the 50 micrograms dose. No endometrial stimulation was detected in any of the patients after treatment with 25 micrograms daily. Beneficial clinical and cytological effects were obtained with both dosage regimens. Daily intravaginal administration of 25 micrograms E2 can accordingly be advocated for the treatment of urogenital symptoms attributable to oestrogen deficiency in post-menopausal women.

Administration, Intravaginal↗

The phospholipase A2-induced increase in the permeability of phospholipid membranes to Ca2+ and H+ ions.

The permeability of liposomes prepared from beef heart mitochondrial phospholipids was studied after treatment with phospholipase A2. The permeability to H+ ions was measured by recording the rate of change of pH in the external medium following an addition of an aliquot of alkali to liposomes with a highly buffered inner medium, while the penetration of Ca2+ ions into liposomes was measured in liposomes loaded with arsenazo III. There was a doubling of H+ permeability when the lysophospholipid content was increased to 2% by treatment with phospholipase A2, and a tripling at 4%. Entrapped sucrose leakage from liposomes became apparent at above 6% lysophospholipid. Treatment with phospholipase A2 stimulated Ca2+ penetration into liposomes driven by a valinomycin-induced diffusion potential or a nigericin-induced H+ gradient. The data are discussed in relation to the mechanism of damage to mitochondria occurring in Ca2+ overload as well as in phospholipase A2-induced cellular damage.

Animals↗

Response of Plasmodium falciparum to chloroquine treatment: relation to whole blood concentrations of chloroquine and desethylchloroquine.

A standard treatment with 25 mg chloroquine base per kilogram body weight was given to 39 semi-immune asymptomatic Tanzanian schoolchildren with Plasmodium falciparum parasitaemia. Whole blood chloroquine and desethylchloroquine concentrations were monitored 12 times during 30 days of follow-up using 100 microliters capillary blood dried on filter-paper. All but three children had detectable amounts of chloroquine (greater than or equal to 10 nmol/l) in their blood before treatment. The interindividual variations in concentrations during the first week were 3.3 to 5.1-fold for chloroquine and 3.5 to 6.3-fold for desethylchloroquine. In seven children with RII response in vivo, the highest determined chloroquine concentration was lower (P = 0.029) than in the others. After treatment, a rough approximation of the minimum inhibitory concentration in vivo was made by calculating the average of the chloroquine concentrations before and after the time when parasites increased or reappeared again. RII-resistant parasites increased in number when the median residual whole blood concentration in the children was approximately 790 (range, 444-869) nmol/l. Parasites reappeared when the median residual whole blood concentrations was approximately 147 (range, 44-673) nmol/l. We conclude that interindividual variations of chloroquine concentrations have an impact on the outcome of treatment and the classification of resistance in vivo.

Adolescent↗

Shiga-like toxin production and connective tissue protein binding of Escherichia coli isolated from a patient with ulcerative colitis.

A 15-year-old girl with her first relapse of ulcerative colitis was treated with salicylazosulfapyridine, steroids, metronidazole and parenteral nutrition for 4 weeks without significant improvement. Her faecal specimens were negative for established intestinal pathogens, but strains of Escherichia coli producing Shiga-like toxin and expressing binding of fibronectin and collagen were repeatedly isolated. Neutralizing antibodies to Shiga-like toxin were detected in serum samples. Improvement was achieved during treatment with mecillinam to which the E. coli strains were sensitive.

Adolescent↗

Oral N-acetylcysteine reduces selected humoral markers of inflammatory cell activity in BAL fluid from healthy smokers: correlation to effects on cellular variables.

Bronchoalveolar lavage (BAL) was performed on eleven healthy smokers before and after eight weeks of oral treatment with N-acetylcysteine (NAC) 200 mg t.i.d. The concentrations of selected eosinophil and neutrophil granule constituents and of selected proteases and protease inhibitors, albumin and endotoxin were determined in the recovered BAL fluid and in plasma or serum samples. In addition, in vitro chemotactic activities for neutrophils and eosinophils were assessed in the BAL fluid. Significant reductions in BAL fluid content of lactoferrin (LF), eosinophil cationic protein (ECP), antichymotrypsin (ACT) and chemotactic activity for neutrophils were recorded after NAC treatment. The levels of other examined markers tended to be reduced or were not affected. In serum/plasma, the concentrations of myeloperoxidase (MPO) and elastase were reduced after NAC treatment whereas concentrations of other constituents examined were unaltered. These data, together with previously reported findings, suggest that oral NAC may influence the activity of "inflammatory" cells in the bronchoalveolar space of smokers.

Acetylcysteine↗

A search for a model tissue for studying effects of thiazide diuretics.

A search was made for a model tissue of NaCl absorption which would be sensitive to inhibition by diuretics of the thiazide type. A lack of such a model through the years has hampered the analysis of the cellular mechanism of action of this important class of drugs. Using the short-circuit current technique, the urinary bladders of the toads Bufo spinosus and Bufo marinus, and the frog Rana temporaria were investigated regarding the effects of various thiazides. These bladders have NaCl absorptive properties similar to those of the distal renal tubules, and are claimed to be sensitive to the inhibitory effect of thiazides on sodium transport. The short-circuit current (SCC), which is representative of the sodium transport across the epithelium, was reduced by cyclopenthiazide and polythiazide, but only at high concentrations (above 0.1 mM). To rule out the possibility that this was an unspecific effect, attempts were made to block the effect by the 'thiazide blocker' Ex 4877, but without success. This finding, together with the fact that dose-response curves were difficult to obtain, would indicate that these epithelia are not suitable for the stated purpose. Preliminary studies were also conducted on the urinary bladder of the plaice, Pleuronectes platessa, which has a different system of NaCl absorption that is claimed to be rapidly and reversibly inhibited by thiazides. Polythiazide, added to both sides of the bladder, had no effect on SCC.

Animals↗