Biomedical subjects
H Eriksson
Publications and source records attributed to H Eriksson.
Gallstone formation in guinea pigs under different dietary conditions. Effect of vitamin C on bile acid pattern.
Guinea pigs formed gallstones when fed chow supplemented with cholesterol and cholic acid. Although the stones contained little or no cholesterol the changes in biliary bile acid and lipid composition were similar to those observed in other rodents under conditions of cholesterol gallstone formation. Addition of cholestyramine to chow had a midly lithogenic effect. Hypovitaminosis C in animals given cholesterol and cholic acid resulted in an increase of the cholesterol content of the gallstones. The composition of biliary bile acids was markedly changed. Reductive formation of deoxycholic acid decreased and oxidative formation of ketonic bile acid increased. The results show that vitamin C may influence the redox state of the intestinal microorganisms microorganisms responsible for these conversions.
A reliable way of estimating cholinesterases from whole blood in the presence of anti-cholinesterases.
A method for the determination of cholinesterases [1] has been adapted to monitor these enzymes in the presence of anti-cholinesterase insecticides. The cholinesterases in blood samples, which were dried on filter papers, could be eluted with water (plasma cholinesterase) and with 1% Triton X-100 (erythrocyte acetylcholinesterase) with complete recovery of the enzyme activity. The samples could be stored at room temperature for at least two weeks and in a refrigerator more than six weeks without a decreased efficiency of elution from the filter paper. It was found that if blood samples to which the two insecticides, used to test the validity of the method, had been added, were stored on filter paper at room temperature or deep frozen for at least one week, there was the same inhibition of the cholinesterases as at the start of the experiment. The samples stored at room temperature in tubes, recovered maximally within a day. This modified method of cholinesterase determination will be especially suitable when samples have to be mailed to laboratories making the analysis.
Heterogeneity of estrogen binding sites: relationship to estrogen receptors and estrogen responses.
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Cholinesterase activity of whole blood and plasma in amyotrophic lateral sclerosis.
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The effect of transcutaneous electric nerve stimulation on ischemic pain in the lower extremities.
The effect of transcutaneous nerve stimulation (TNS) on ischemic pain in the lower extremities was tested. Eleven patients with severe arterial insufficiency were observed before and after TNS. The results indicate pain relief and increased walking distance in all subjects. We interpret the results of this study that ischemic pain can be diminished by TNS.
A mechanistic model for butyrylcholinesterase.
A plausible mechanism of action of horse serum butyrylcholinesterase is proposed. It includes substrate activation at the level of deacylation. The rate constant for the acylation of the enzyme appears to be much greater than the rate constant for the deacylation, at low substate concentrations. At higher substrate concentrations the rate constants become more similar. No interaction between the four subunits in binding of inhibitors or in the catalysis was observed. There is one esteratic and one anionic site per subunit apparent from labelling studies with [32P]diisopropylfluorophosphate and binding studies with N-methylacridine. Although the tetrametric form of the enzyme appears to be the native one, the monomeric and several other aggregated and dissociated states are catalytically active.
Nuclear binding of the estrogen receptor: heterogeneity of sites and uterotropic response.
Two kinds of estradiol binding sites are present in purified nuclei from the rat uterus following estradiol injection. One of these sites (type I) corresponds to the well-known estrogen receptor which undergoes translocation from the cytoplasm to the nucleus. The second site (type II) is not translocated from the cytoplasm to the nucleus, however, estradiol treatment does stimulate an increased number of these sites. Type II sites are observed in purified nuclei and chromatin isolated from the uterus but not from non-target tissues such as the spleen and diaphragm. Thus an elevation in the levels of type II sites appear to be a specific nuclear response of the rat uterus to estradiol. Saturation analysis over a wide range of [3H]-estradiol concentrations produces a binding curve for type II sites which is sigmoidal and hence no accurate estimation of the dissociation constant is possible. The binding of [3H]-estradiol to nuclear type II sites is inhibited by estradiol and diethylstilbestrol but not by progesterone, testosterone, or corticosterone. Extraction of nuclei isolated from estrogen treated rat uteri with KCl provides a complex picture. Direct labeling of nuclear estrogen receptors either by in vivo injection or in vitro incubation of intact uteri with [3H]-estradiol measures only a fraction of the specific estrogen binding sites associated with the nuclear pellet following 0.4 M KCl extraction. These sites are more accurately determined by performing saturation analysis over a wide range of [3H]-estradiol concentrations by exchange which measures specific estrogen binding sites, not [3H]-steroid. Saturation analysis of estradiol binding to KCl extracted nuclei when performed by exchange, with appropriate corrections for type II binding, reveals that approximately 1000--2000 receptors per nucleus are resistant to KCl extraction 1 hr after administration. The same numbers of type I sites display long-term nuclear retention. A single injection of estradiol results in long term (greater than 6 h) retention of type I sites, rapid and sustained elevations (1--72h) in type II sites and true uterine growth (uterine wet weight at 24--43 h). Estriol injections caused a rapid increase in nuclear type I sites which was not accompanied by an increase in type II sites and no true uterine growth occurred. Administration of estriol or estradiol as a pellet implant, which causes continuous occupancy of type I sites, increases the quantity of nuclear type II sites and stimulates true uterine growth. Therefore, we conclude that elevated levels of nuclear type II sites correlate with the long term uterotropic response to estrogenic hormones. Although we do not understand the function of this second class of binding sites it is possible that the type II sites represent a major component in the mechanism by which estrogens stimulate growth of the uterus.
Insulin response to an oral glucose load in relation to Lp(a)/pre-beta 1-lipoprotein levels in non-diabetic patients with peripheral vascular disease and in controls.
An oral glucose tolerance test (OGTT) was performed in 21 patients with previously known or recently detected peripheral vascular disease as well as in 16 age-matched controls. The angiographic results and the results in a physiological investigation were used to classify patients with high and low stenosis and normal controls, respectively. No significant differences in mean levels of insulin and blood glucose were found between patients with high and low stenosis, respectively, or between normal controls and (a) the whole group of patients with high stenosis, (b) only those with high stenosis who had not undergone arterial surgery. However, individuals with high amounts of Lp(a) lipoprotein were found to have significantly lower insulin mean levels during the OGTT and an even lower mean fasting level as compared to individuals without detectable Lp(a) lipoprotein. In the group of individuals with high amounts of Lp(a) lipoprotein, the glucose mean levels were also significantly lower, during a part of the OGTT. These findings are in agreement with previous results and suggest that inherited metabolic differences exist between individuals with high and zero or low levels of Lp(a) lipoprotein.
Heterogeneity of estrogen binding sites in the cytosol of the rat uterus.
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A new approach to determining cholinesterase activities in samples of whole blood.
A sensitive method, especially suitable for clinical laboratories, for the routine determination of cholinesterase activities in whole blood is presented. This method is based on the hydrolysis of propionylthiocholine and the spectrophotometric determination of the thiocholine produced by reaction with 4,4'-dithiodipyridine. The reaction product 4-thiopyridone has an absorption maximum at 324 nm, so that measurement in the presence of hemoglobin is possible. Propionylthiocholine is used at the substrate for both plasma butyrylcholinesterase and erythrocyte acetylcholinesterase. These two enzymes, in the relative amounts at which they are present in human blood, split this ester at about the same rate. Consequently, a first determination gives the total activity of which each individual activity is about 50%. A second determination in the presence of a selective inhibitor ("Astra 1397") for plasma butyrylcholinesterase gives the activity of the erythrocyte acetylcholinesterase. The difference between the two values represents the activity of the plasma enzyme. The validity of the method and the reliability of the results were checked with each blood sample in two ways: (1) by determining the activities of whole blood with an earlier gasometric technique which uses blood sample dried on filter paper; and (2) by measuring the activities in separated plasma and erythrocyte hemolysate eith propionylthiocholine as the substrate.
Heterogeneity of estrogen receptors in the cytosol and nuclear fractions of the rat uterus.
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[Biochemical and clinical aspects of the intracellular activity of steroid hormones].
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Nuclear estrogen receptor in the avian liver: correlation with biologic response.
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Methods for assessing the binding of steroid hormones in nuclei and chromatin.
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Treatment of ischemic ulcers using EPIGARD--a synthetic dressing [proceedings].
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B-cell activation of peripheral blood lymphocytes from patients with chronic lymphatic leukaemia.
The mitogenic response of blood lymphocytes from twelve patients with B-cell CLL and seven healthy controls was investigated. All patients were untreated and had a typical B-cell dominance in their peripheral blood. The patients demonstrated a scattered response pattern with a higher variance than in the control group. We demonstrated examples of stimulation of DNA-synthesis by polyclonal B-cell activators (PBA) as well as inhibition. The variable pattern between the patients might result from a malignant transformation of cells originating from different lymphocyte subpopulations in different patients. Thus PBA studies of lymphocytes from CLL patients might be a valuable tool in characterizing further this clinically variable disease at the cellular level.
Occurrence of sulfated 5alpha-cholanoates in rat bile.
Bile acids in bile from male and female rats with cannulated bile ducts have been analyzed by repetitive scanning gas-liquid chromatography-mass spectrometry after initial fractionation of conjugate classes on diethylaminohydroxypropyl Sephadex LH-20. Sex differences were observed in the amounts and types of bile acids in the sulfate fraction. The proportion of total bile acids excreted as sulfates was higher in female (0.9-1.3%) than in male (0.1-0.2%) rats. Most of the sulfated bile acids had a 5alpha configuration, allochenodeoxycholic acid being the major compound in bile from female rats. This bile acid was also present in the nonsulfate fraction but could not be found in bile from male rats. The results indicate that gas-liquid chromatography-mass spectrometry has to be used to provide sufficient specificity in the bile acid analyses. Thus, compounds from the sulfate fraction having the retention times of cholic and chenodeoxycholic acid derivatives were found to be due to derivatives of the 3beta,5alpha-isomers of these bile acids.