Showing papers by "Uppsala University published in 1975"

Metal chelate affinity chromatography, a new approach to protein fractionation

Abstract: CONVENTIONAL nonspecific precipitation methods sometimes depend on affinities which can be used in a more selective fashion by modern chromatographic techniques. The affinity of proteins for heavy metal ions, for example, may provide a basis for their purification and analysis. A highly flexible method based on such affinities is described here.

"Natural" killer cells in the mouse. I. Cytotoxic cells with specificity for mouse Moloney leukemia cells. Specificity and distribution according to genotype.

Abstract: In the spleens of young, adult mice there exist naturally occurring killer lymphocytes with specificity for mouse Moloney leukemia cells. The lytic activity was directed against syngeneic or allogeneic Moloney leukemia cells to a similar extent, but was primarily expressed when tested against in vitro grown leukemia cells. Two leukemias of non-Moloney origin were resistant and so was the mastocytoma line P815. Although killer activity varied between different strains of mice, the specificity of lysis was the same as indicated by competition experiments using unlabeled Moloney or other tumor cells as inhibitors in the cytotoxic assays. Capacity to compete and sensitivy to lysis by the killer cells were found to be highly positively correlated. Analysis of the kinetics of the cytotoxic assay revealed a rapid induction of lysis within one to four hours, arguing against any conventional in vitro induction of immune response. No evidence was found of soluble factors playing any role in the cytolytic assay.

Estimation of a Model with Multiple Indicators and Multiple Causes of a Single Latent Variable

Abstract: We consider a model in which one observes multiple indicators and multiple causes of a single latent variable. In terms of the multivariate regression of the indicators on the causes, the model implies restrictions of two types: (i) the regression coefficient matrix has rank one, (ii) the residual variance-covariance matrix satisfies a factor analysis model with one common factor. The first type of restriction is familiar to econometricians and the second to psychometricians. We derive the maximum-likelihood estimators and their asymptotic variance-covariance matrix. Two alternative “limited information” estimators are also considered and compared with the maximum-likelihood estimators in terms of efficiency.

"Natural" killer cells in the mouse. II. Cytotoxic cells with specificity for mouse Moloney leukemia cells. Characteristics of the killer cell.

Abstract: Normal mice contain cytolytic cells with specificity for in vitro grown mouse Moloney leukemia cells. Such killer cells are most frequent in the spleens; lymph node and bone marrow contain less and thymus virtually no killer activity. Peak activity is found around one to three months of age. Spleen cells from genetically athymic mice are as active killer cells as those from normal mice of the same strain. Treatment with anti-theta serum plus complement followed by removal of adherent and surface Ig positive cells by filtration through anti-Ig columns will leave between 1-5% of the original spleen cell population from a normal mouse. These cells have the morphology of small lymphocytes and perhaps contain all of the total original killer activity of the spleen against the Moloney leukemia cells. Such killer enriched cells are devoid of T and B lymphocytes and largely fail to function in antibody induced, cell-mediated lysis against antibody-coated chicken erythrocytes. It is concluded that the spontaneous selective cytotoxic activity of normal mouse spleen cells against Moloney leukemia cells is exerted by small lymphocytes of yet undefined nature.

Self-consistent reaction field theory of solvent effects

Abstract: A quantum-mechanical reaction field theory of solvent effects is proposed. It contains as a limiting case Onsager's model. It leads to an effective, non-linear, hamiltonian for the molecule in solution and hence to a tool for studying changes in charge distributions and molecular properties. Numerical examples are given.

Convex set functions ind-space

Abstract: Given subsets A and B of Euclidean d-space R a and 0 ~ 0, we set A + B -{x + Y l x E A, y E B} and OA = {Ox Ix 6 A }. Further given a convex subset g2 of R d we shall say that a set function F : 2 ~ \ {~} ~ [0, + ~ ] is convex (concave} if the inequality F(OA + (1 O)B) ~ Or(A} + (1 0 ) / ' ( B ) (>=.) holds for all It ~ A, B c_ D, and all 0 < 0 < 1. Here we shall s tudy such set functions of the special form given in the following

Factor analysis of dichotomized variables

Abstract: An approach for multiple factor analysis of dichotomized variables is presented. It is based on the distribution of the first and second order joint probabilities of the binary scored items. The estimator is based on the generalized least squares principle. Standard errors and a test of the fit of the model is given.

Classification and biological nature of established human hematopoietic cell lines

Abstract: Over 200 established human hematopoietic cell lines of normal and malignant origin have been investigated by morphological and functional parameters. Employing morphology as the overriding parameter four types of lines were identified. (1) Lymphoblastoid cell lines, derived from normal and neoplastic hematopoietic tissue, were characterized by the wide morphologic flexibility of individual lymphoblastoid cells, constant association with Epstein-Barr virus (EBV), polyclonal derivation, differentiation for immunoglobulin production (secretion) and their diploids. (2) Lymphoma cell lines. This type of line was established at a high frequency from Burkitt's lymphoma and rarely from other types of lymphoma, but never from patients without malignancy or with non-lymphoma malignancies. Important characteristics were morphologic stereotypia within each line, monoclonal derivation, common but not obligatory association with EBV, variability in the expression of Ig synthesis (no production, or membrane bound Ig, or secretion) and aneuploidy. (3) Myeloma cell lines could only rarely be obtained from patients with myeloma. The basis for classification of these lines is their production of Ig identical to the myeloma protein in vitro. Other important distinguishing features were: plasma cell morphology, absence of EBV and aneuploidy. (4) The leukemia cell line (MOLT 4) was the only line with T-cell characteristics and was easily distinguished from the other types. Important characteristics were a typical surface ultrastructure, absence of EBV and absence of immunoglobulin production, Individual lymphoblastoid lines were in principle identical whereas each line of the other three types had its own characteristic profile. The phenotypic characteristics of the lymphoblastoid lines were very stable during prolonged serial cultivation. Only in a few cases were secondary chromosomal, functional or morphologic alterations noted. We conclude that EBV-carrying lymphoblastoid lines can be obtained from non-neoplastic precursor cells from healthy as well as from diseased individuals. Lymphoma, myeloma and leukemia lines are only obtained from the respective neoplastic tissue but generally at a low frequency. With the exception of Burkitt's lymphoma, malignant hematopoietic tissue and leukemia frequently give rise to established cell lines in vitro of the lymphoblastoid type rather than lines derived from the neoplastic cells;

The primary structure of allergen M from cod.

Abstract: The complete primary structure of allergen M of cod (Gadus callarias L.) is presented. The amino acid sequence of fragment TM1, the NH2-terminal peptide of allergen M, was elucidated by the dansyl-Edman method. It consists of 75 amino acids and 1 glucose residue (mol. wt. 8,492). By summation of the sequence data of fragment TM1 and the previously reported fragment TM2, the intact allergen M has 113 residues (mol. wt. 12,328). Fragment TM1 of cod shows less homology (30.6 percent) with the corresponding fragments of other reported fish species than does fragment TM2 (42.1 percent); the intact allergen M shows 34.5 percent homology. The single half cystine of allergen M was shown to be blocked. Gas chromatographic analysis of the reduced and nonreduced allergen M suggested that the glucose is bound to Cys 18 through an S-glucosidic bond.

Pathological responses of rat skeletal muscle to a single subcutaneous injection of a toxin isolated from the venom of the Australian tiger snake, Notechis scutatus scutatus

Abstract: SUMMARY 1. The pathology of mammalian skeletal muscle following a single subcutaneous injection of a purified toxin from the venom of the Australian tiger snake, Notechis scutatus scutatus, has been investigated. 2. The toxin was injected into the antero-lateral aspect of one hind limb of rats and the effects of the injection on the histology, histo-chemistry and physiology of the extensor digitorum longus muscles were studied. 3. The muscles underwent degenerative necrosis, with oedema and the infiltration of lymphocytes, polymorphs and macrophages within 12–24 h after the injection. 4. Three days after injection, the oedema had subsided and the necrotic fibres had been completely destroyed by phagocytes. Small uninucleate cells, with basophilic cytoplasm and vesicular nuclei were present at this stage; on the basis of these criteria they were identified as regenerating myoblasts. 5. By 5 days the myoblasts had fused to form myotubes, but differentiation of the myotubes into histochemically distinct muscle fibre types did not commence until around 7 days after the injection. 6. Regeneration and differentiation was virtually complete by 21 days after injection. 7. Between 3 and 5 days, many of the fibres were sensitive to acetylcholine, and muscle fibre action potentials were resistant to tetrodotoxin. Miniature end-plate potentials were of low amplitude and frequency; they may have been absent from many fibres. 8. By 7–10 days, the proportion of fibres with tetrodotoxin-resistant action potentials was declining, and acetylcholine sensitivity was less marked; miniature end-plate potentials, though of normal amplitude, were of reduced frequency. The fibres were virtually normal by 14–21 days. 9. It is considered likely that these physiological properties were recorded from regenerating muscle fibres that reached maturity by 28 days; the possibility that they were recorded from functionally denervated fibres is discussed. 10. The rapid rate of regeneration and differentiation of the toxin-damaged muscle was sustained only if the peripheral nerve supply was left intact. 11. Preliminary results suggested that mitochondria-rich fibres were preferentially damaged by the toxin, and that the toxin is less active in vitro than in vivo. These problems are currently being investigated. 12. It is concluded that the toxin has a direct myotoxic effect on muscles; the relationship of this effect to the previously described neurotoxic effect is also currently under investigation.

Detection of correlated errors in longitudinal data

Abstract: A study of change in ability between two occasions may employ a number of tests believed to measure the ability in question. Either the same battery of tests is used on both occasions, or equivalent forms are used. For a variety of reasons, correlations may exist between certain errors remaining after eliminating variance due to true scores, and hence the classical factor analysis model is not applicable. A procedure for detecting correlations between errors is discussed. A search strategy is proposed since, even if the number of observed variables is small, the number of possible models is very large. A computer program is described, which produces maximum-likelihood estimates for the parameters in a factor analytic model in which the error variables may be correlated.

Supplier Selection in an International Environment-An Experimental Study

Abstract: This experiment indicates the important influence of the location of the supplier when the industrial purchaser selects a supplier. The results also indicate, contrary to interview studies, that pr...

The Rate of Strand Separation in Alkali of DNA of Irradiated Mammalian Cells

Abstract: When mammalian cells are treated with alkali of pH at about 12, the cells are lysed and the released DNA starts to uncoil. This process of DNA strand separation is accelerated if the cells have been exposed to ionizing radiation, and the effect is clearly detectable in the dose range 10–100 rads. The rate of strand separation is also influenced by temperature and ionic strength of the alkaline solution. The kinetics of DNA strand separation in alkali is studied for three conditions in terms of ionic strength and temperature, chosen in such a way that the effect of irradiation may conveniently be studied in the dose range 10 rads to 20 krads. The accelerating effect of ionizing radiation on DNA strand separation is probably due to DNA strand breakage and the technique described is thus a sensitive method of studying such damage to DNA. A model for the strand-separation process, based on the assumption that strand breakage causes the accelerating effect, is proposed and found to describe the experimental da...

Assessment in the guinea-pig ileum and mouse vas deferens of benzomorphans which have strong antinociceptive activity but do not substitute for morphine in the dependent monkey

Abstract: 1 Four benzomorphans which have potent antinociceptive activity in the hot-plate and writhing tests in the mouse but do not suppress or precipitate withdrawal symptoms in the morphine-dependent monkey, have been examined for their pharmacological actions in the guinea-pig ileum and mouse vas deferens 2 In the guinea-pig ileum their agonist potencies are 15 to 400 times greater than that of normorphine of morphine whereas in the mouse vas deferens their potencies relative to morphine are 03 to 100 They exhibit no antagonist activity in either preparation Benzomorphans which substitute for morphine in the morphine-dependent monkey do not show such differences between their relative potencies in the guinea-pig ileum and mouse vas diferens 3 The relative potencies of the four benzomorphans to inhibit stereospecific [3H]-dihydromorphine binding by membrane fragments from rat brain, are more closely related to their relative agonist potencies in the mouse vas deferens than to those found in the guinea-pig ileum 4 In order to antagonize the agonist actions of these benzomorphans, naloxone is required in concentrations which are 3 to 7 times higher than those needed for the antagonism of normorphine or morphine or of benzomorphans which suppress abstinence in morphine-dependent monkeys 5 It may be possible to use the three assays, namely, ratio of relative agonist potency in mouse vas deferens to that in guinea-pig ileum, ratio of relative agonist potency to relative affinity to opiate receptors and the concentration of nalozone required for antagonism, for the prediction of the potential of new compounds to produce physical dependence

One-trial learning and superior resistance to extinction of autonomic responses conditioned to potentially phobic stimuli.

Abstract: Human subjects were exposed to pictures of potentially phobic (snakes) and supposedly neutral (houses) objects as conditioned stimuli (CSs) in a Pavlovian conditioning experiment with shock as unconditioned stimulus (US), and skin conductance and finger pulse volume as dependent variables. The skin conductance responses conditioned to phobic stimuli were acquired after one CS-US pairing, and showed practically no extinction, whereas the responses to neutral stimuli showed very little resistance to extinction after both 1 and 5 reinforcements . The superior resistance to extinction of the phobic condition was interpreted to be a specific associative effect. In general, the skin conductance acquisition data showed tendencies similar to those during extinction. For finger pulse volume responses, however, there were very weak conditioning effects, and no effect of stimidus. Ever since its inception as an experimental field of investigation, the psychology of learning has been dominated by associationistic theories. A fundamental assumption within this theoretical framework has been that associations can be studied independent of the associated elements. In other words, the laws of learning have been regarded as valid without qualifications in terms of the kinds of stimuli, responses, or reinforcements involved. Recently, this "premise of equipotentiality" has been persuasively challenged by Seligman (1970), and the argument is substantiated by readings compiled by Seligman and Hager (1972).

Arterial hypotension and hypoxaemia during total hip replacement: the importance of thromboplastic products, fat embolism and acrylic monomers.

Abstract: Thirteen patients submitted to total hip replacement surgery by the Charnley technique were studied. Operations were performed under epidural analgesia with the patients awake and breathing air. During the surgical procedure, the magnitude of tissue-thromboplastic activity, the amount of fat globules, the presence of bone marrow cells and the concentrations of acrylic monomers were determined in the pulmonary arterial blood. Simultaneously, arterial blood gases and blood pressure were monitored. Marked reductions of the arterial blood pressure and arterial oxygen tension occurred after impaction of the femoral prosthesis, and minor depressions appeared after insertion of the acetabular prosthesis. A significant correlation was found between the release of tissue-thromboplastic products into the pulmonary circulation, i.e., products that initiate intravascular coagulation and the circulatory and respiratory reactions. The pulmonary fat droplets, per se, seem to be of minor importance, and the release of acrylic monomers is probably of no importance for these reactions. ZUSAMMENFASSUNG 13 Patienten, bei denen ein totaler Huftgelenksersatz nach Charnley durchgefuhrt wurde, dienten als Grundlage dieser Stuide. Die Operationen erfolgten in Epiduralanaesthesie, die Patienten waren wach und atmeten Luft. Wahrend des Eingriffes wurden das Ausmas der thromboplastischen Gewebsaktivitat, die Menge der Fett-trofchen, das Vorhandensein von Knochenmarkszellen und die Konzentration der Akrylmonomeren kontinuierlich im Pulmonalarterienblut bestimmt. Gleichzeitig wurden arterielle Blutgase und Blutdruck registrert. Nach dem Einzementieren der Femoralprothese kam er reglmasig zu ausgepragter Atem- und Kreislauf-depression, nach Einsetzen der Azetabularprothese traten geringere Dampfungen afu. Als Resultat unserer Untersuchungen steht fest, das die zirkulatorischen und respiratorischen Phanomene hauptsachlich durch die Freisetzung gewebsthrombopulasticher Produkte in dne Kreislauf verursacht werden, namlich Produkte, die zu intravaskularer Koagulation (Aggregation von Thrombozyten und Fibrin) fuhren. Die Fett-trofchen an sich sind von geringer Bedeutung, die Freisetzung von Akrylmonomeren wahrscheinlich irrelevant.

Protein A from Staphylococcus aureus

Abstract: Protein A, a cell-wall protein from Staphylococcus aureus, has been studied by spectrophotometry and spectropolarimetry. All the four tyrosines are similarily titrated with pKa= 10.25. Circular dichroism (CD) spectra show that the conformation of protein A is very stable over a large pH interval (0.99–11.8). The conformation is partly intact even in 6 M guanidine hydrochloride and at 80°C. Protein A contains about 50%α-helical structure and 10–20%β-structures. CD band maxima at 261 and 268 nm are ascribed to transitions in the phenylalanine residues and ellipticities between 275–285 nm to the tyrosine residues. Of the four tyrosines, 3.5 are perturbed by 20% polyethylene glycol, while all of them are perturbed by 20% dimethylsulfoxide. The role of the tyrosines in the reaction with the Fc-region of immunoglobulins is discussed.