Showing papers by "Uppsala University published in 1979"

Maximum likelihood estimation of the polychoric correlation coefficient

Abstract: The polychoric correlation is discussed as a generalization of the tetrachoric correlation coefficient to more than two classes. Two estimation methods are discussed: Maximum likelihood estimation, and what may be called “two-step maximum likelihood” estimation. For the latter method, the thresholds are estimated in the first step. For both methods, asymptotic covariance matrices for estimates are derived, and the methods are illustrated and compared with artificial and real data.

An intermediate neglect of differential overlap theory for transition metal complexes: Fe, Co and Cu chlorides

Abstract: A complete Intermediate Neglect of Differential Overlap model suitable for the examination of transition metal complexes is described. The model is characterized by the inclusion of all the one-center exchange terms necessary for rotational invariance and accurate spectroscopic predictions, as well as an accurate description of integrals involving 3d atomic orbitals. The model is within the unrestricted Hartree-Fock formalism, and a method for spin purification is described. Problems with convergence of the self-consistent field are discussed, and a method that has been found successful in aiding the convergence is outlined. The model has been applied to many transition metal systems. In this article the results of calculations on the chlorides of Fe, Co and Cu are described. The results of these calculations are compared with experiment, and with the results of calculations by other methods.

K562--a human erythroleukemic cell line.

Abstract: We have studied the surface membrane properties of the human leukemic cell line K562 which previously has been reported to represent an early stage of granulocyte maturation. The surface glycoprotein pattern of the K562 cells obtained after galactose oxidase-NaB[3H]4 labelling and slab gel electrophoresis shows striking similarities with that of normal erythrocytes but is completely different from the patterns of normal and malignant cells of various stages of the myeloblast to granulocyte differentiation. Moreover, the K562 cell expressed the major red cell sialoglycoprotein, glycophorin, on its surface as shown by immunofluorescence and by immunoprecipitation from labelled membrane preparations. As glycophorin is exclusively found on erythroid cells in human bone marrow we conclude that the K562 is a human erythroleukemic line.

Binding of Drugs to Human Serum Albumin:: XI. The Specificity of Three Binding Sites as Studied with Albumin Immobilized in Microparticles

Abstract: Human serum albumin can be immobilized in spherical, macroporous microparticles of polyacrylamide of about 1 µm in diameter with retention of its native properties. It has been shown that diazepam, digitoxin and warfarin independently bind to albumin and can conveniently be used as markers of three separate, discrete binding sites on albumin. A simple technique has been devised by which the capacity of about 140 drugs and other compounds to affect the binding of the radioactively labeled markers has been studied. Some drugs, e.g. antirheumatic drugs of the isopropionic acid-type, some antidiabetic agents, penicillin derivatives, benzodiazepines, tryptophan, dansylsarcosine, and suiphobromophthalein efficiently displace diazepam. Other drugs, e.g., some diuretics, sulpha drugs, phenytoin, salicylic acid and butazone derivatives, azapropazoe, bilirubin, and dansylamide displace warfarin. Displacement of digitoxin is less common. In some cases the binding of the markers is improved, e.g., tamoxifen increases the binding of warfarin. Both competitive and allosteric mechanisms are responsible for the changed binding of the markers. Some results suggest the presence of more than the three binding sites for drugs on the albumin surface studied with diazepam, digitoxin and warfarin.

Structure of two spliced mRNAs from the transforming region of human subgroup C adenoviruses

Abstract: The papova viruses and the human adenoviruses are widely used as a model system to study cell transformation in vitro. In subgroup C human adenoviruses, fragment HpaI-E, which comprises as little as 4.5% of the adenovirus type 5 (ad5) DNA, is sufficient for transformation of rat embryo cells1. Analysis of messenger RNAs (mRNAs) from the transforming region of adenoviruses type 2 (ad2) has identified several spliced mRN A species2–4. Promoter mapping studies indicate that the leftmost early region contains two separate transcription units, E1A and E1B (ref. 5) (Fig. 1a). Region E1A is approximately equivalent HpaI-E. The complete nucleotide sequence of the HpaI-E fragment of ad5 was recently reported6. However, the spliced nature of early adenovirus mRNAs prevents a prediction of the amino acid sequence of the corresponding polypeptides directly from the DNA sequence. To study the structure of early ad2 mRNAs at the nucleotide level, we have used molecular cloning procedures to amplify the appropriate mRNA sequences. In this report, clones corresponding to the 12S and 13S mRNA from region E1A (Fig. 1c) have been isolated and characterised by hybridisation and sequence analysis. Our results enable us to predict the primary sequence of two related polypeptides from region E1A of human subgroup C adenoviruses.

Post-mortem distribution of dopamine and homovanillic acid in human brain, variations related to age, and a review of the literature.

Abstract: The post-mortem brain concentrations of dopamine (DA) and homovanillic acid (HVA) were determined in 16 parts of the brain from patients with no history of neurologic or psychiatric illness. Fifteen men and nine women, with a mean age of 61.0 +/- 18.7 years (range 23--92 years) were included. They had died from either ischaemic heart disease or cancer. In the post-mortem investigation several factors were controlled: age, time between death and autopsy, time between autopsy and chemical analysis and storage time (-20 degrees C). The DA concentrations in the different brain areas were found to be positively intercorrelated, especially those in the basal ganglia, hippocampus and the mesencephalon. The HVA concentrations measured in various cortical structures were also positively intercorrelated. In several regions of the brain there was a significant inverse correlation between the DA and HVA concentrations. The DA and HVA concentrations did not differ according to sex, but age had a marked influence on the DA concentration. Significant decrease with age was observed in the nucleus caudatus, globus pallidus, mesencephalon, hippocampus and in the cortex gyrus hippocampus. These findings are discussed in relation to the effect of aging neurons. A review of human post-mortem investigations on DA and HVA concentrations is also presented.

A Structural Probit Model with Latent Variables

Abstract: A model with dichotomous indicators of latent variables is developed. The latent variables are related to each other and to a set of exogenous variables in a system of structural relations. Identification and maximum likelihood estimation of the model are treated. A sociological application is presented in which a theoretical construct (an attitude) is related to a set of background variables. The construct is not measured directly, but is indicated by the answers to a pair of questionnaire statements.

A rapid method for the separation of functional lymphoid cell populations of human and animal origin on PVP-silica (Percoll) density gradients.

Abstract: Subclasses of lymphocytes can be separated on gradients of non-toxic polyvinylpyrrolidone-coated colloidal silica (Percoll) by virtue of differential densities. Such gradients can yield functionally active lymphocyte populations after brief centrifugation. Gradients can he generated in a discontinuous step fashion and centrifuged in standard table-top laboratory centrifuges or as self-generating gradients duriny ultracentrifugation. The density medium has low viscosity and can be made isotonic for virtually any use. Gradients have proved useful in both human and experimental animal studies, and high percentage yields allow for separations from small cell numbers. Methods are described for separation of whole blood and lymphotd subpopulations. including blasts stimulated with mitogens or in mixed lymphocyte reactions. The cytotoxic capability of various density fractions was evaluated for mixed lymphocyte culture-induced allogeneic killing and spontaneous, so-called ‘natural’ killer cell activity. The lower density associated with blast transformation allows for significant enrichments of stimulated cells from in vitro cultures. Higher thymidine incorporation, restimulation in mixed lymphocyte reactions, and greater cytotoxic capacity are associated with these‘blast’fractions.

Senile cardiac amyloidosis: evidence of two different amyloid substances in the ageing heart.

Abstract: In a material of seventy-two persons over 70 years of age. forty-seven cases of amyloidosis of the heart were found. In thirty-nine cases, deposits occurred only in the atria (isolated atrial amyl-oidosis. IAA), while in eight cases amyloid also was seen in the ventricles (senile cardiac amyloidosis, SCA). In some of the latter cases, small amyloid deposits occurred in other organs, especially the lungs. Some definite differences existed between the amyloid substance in SCA and IAA. Thus, tryptophan was demonstrated histochemically in SCA but not in IAA, and, furthermore, amyloid fibrils isolated from patients with IAA lacked protein ASCA, the fibril subunit protein of senile cardiac amyloid. It is concluded that the ageing heart may be the target of two different forms of amyloid, one only affecting the atria, while the other is more widespread within the heart and sometimes also is found in other organs.

Chloroquine serum concentration and side effects: evidence for dose-dependent kinetics.

Abstract: Serum concentrations of chloroquine were determined fluorometrically in 100 rheumatoid patients who had been treated with 0.25 gm daily for at least 2 mo. The total dose varied between 3.7 and 400 gm. No patient received more than 75 gm annually. In 15% of the patients side effects were noted. There was a relationship between serum concentrations and side effects but not with the total dose administered. Chloroquine displayed dose-dependent kinetics, which may indicate that close monitoring of serum concentrations is an aid to the safe and rational use of the drug.

Morphine kinetics in children

Abstract: The kinetics of morphine in the plasma of children (0 to 15 yr) can in most cases be adequately described by a triexponential function. When the dosage in children receiving morphine as premedication before surgery is based on kilograms of body weight, there are only minor differences in the kinetic patterns of morphine at different ages (0 to 1, 1 to 7, and 7 to 15 yr). No significant difference in the morphine kinetics was observed between patients (7 to 15 yr) receiving the drug only as premedication and those who also received doses during surgery. The minimum morphine concentration in plasma necessary to suppress the clinical signs of pain during surgery was found to be 65 ng/ml (95% confidence limits of 46 to 83 ng/ml). Based on these minimum effective plasma levels of morphine, there does not seem to be any difference between children of different ages in their sensitivity to morphine. No difference was found in the minimum effective level of morphine when clinical signs of pain were observed by different anesthesiologists.

Retinal and choroidal contribution to retinal metabolism in vivo. A study in pigs.

Abstract: The glucose metabolism of the retina was studied in vivo, by determining glucose, oxygen and lactate a-v differences for choroidal and retinal blood in pigs at different levels of intraocular pressure. At normal intraocular pressure the choroidal a-v differences were 0.07 and 0.11 mmol/1 for glucose and oxygen respectively. The corresponding figures for the retina were 0.44 and 2.15. At increased levels of intraocular pressure the choroidal and retinal glucose and choroidal oxygen a-v differences increased, thus at least partly compensating for reduced blood flow. A major part of the oxygen and glucose consumed by the retina was delivered by the choroid. The total amount of oxygen extracted from choroidal and retinal blood could only account for complete oxidation of 37% of the extracted glucose. The results obtained in determinations of lactate a-v differences indicate that part of the remaining glucose is used for anaerobic glycolysis.

The Nature of Lymphoid Cell Lines and Their Relationship to the Virus

Abstract: Lymphoid cell lines have been invaluable tools not only in studies of the biologic properties of Epstein-Barr virus (EBV), but also in the fields of oncology, hematology, immunology, genetics, and cell biology. In 1964, Pulvertaft (1964 a) and Epstein and Barr (1964) independently described the first cell lines from tumor biopsies of patients with Burkitt’s lymphoma (BL). Before this, attempts to cultivate normal and malignant hematopoietic tissue in vitro had usually led to a gradual deterioration and subsequent death of the various cell types within weeks or months (Osgood, 1958; Reisner, 1959). Only rarely had permanent cell lines been established from leukemic blood (Osgood and Broke, 1955) and bone marrow (Benyesh-Melnick et al., 1963). In the latter report, the sudden outgrowth of permanent cell lines with a lymphoblastoid morphology was described at a low frequency in fibroblastoid monolayers several weeks after initiation of bone-marrow cultures derived from children with leukemia, infectious mononucleosis (IM) and hemolytic anemia. This remarkable event was termed “lymphoblastoid transformation of fibroblastic bone-marrow cultures.” The meaning of the term “lymphoblastoid transformation” here was thus different from the “lymphoblastoid transformation” used to describe the morphologic changes of normal lymphocytes after exposure to phytohemagglutinin (PHA) (Nowell, 1960).

Marine maceration of skeletal carbonates in the Skagerrak, North Sea

Abstract: Skeletal carbonates in the sediments of the eastern Skagerrak Bay in the North Sea disintegrate into their microscopic structural elements, needles, fibres, flakes, and granules. The process, called maceration, takes place while the carbonates are exposed on the sea-floor, in contact with ambient seawater. All kinds of calcareous shells and skeletons are thus transformed into cryptic lime mud which then may be further dissolved, or redeposited elsewhere, In the area, maceration of carbonates is a major destructive agent, causing severe depletion of calcareous organisms in the fossil record. The diagenetic regime in the Skagerrak is a complete contrast to the classical warm-sea carbonate regime so extensively studied in areas like the Bahama Banks.

Parental adenovirus DNA accumulates in nucleosome-like structures in infected cells

Abstract: Micrococcal-nuclease digestion of adenovirus 2(ad 2) infected HeLa cell nuclei early after infection has been used to investigate the nucleoprotein nature of parental viral DNA. Viral DNA is more susceptible to nuclease digestion than cellular DNA. The pattern of digestion products changes as digestion proceeds from an indistinct pattern 1 hour post infection(pi) to a nucleosome-like pattern at 6 hours pi. The major differences between viral and cellular nucleoprotein products were i) a subnucleosome fraction from viral DNA and ii) the repeat size of DNA in viral nucleosomes was 165 base pairs and in cellular nucleosomes, 195 base pairs. Up to 50% viral DNA in nuclei 6 hours pi seems to be in nucleosome-like structures. Such patterns are not seen on digestion of partially-uncoated virus or isolated cores.

“Case studies” in accounting research

Abstract: Using case studies in accounting research can be meaningful from the perspective of several different “schools of thought” in social science Even if the role and relevance of case methods differ between schools, some general questions nevertheless can be raised In the paper, two types of criticism of case studies are discussed First, the criticism that case studies cannot provide any basis for generalization is argued to originate from an over-emphasis on data and observations and a neglect of theory building in the generation of knowledge Second, it is argued that the statement that case studies are appropriate for generating hypotheses but not for testing them has some truth It is shown, however, that case studies also can play important roles in the “testing” of hypotheses Finally, some advice for case researchers is presented

Cardiovascular and Electrodermal Responses Conditioned to Fear-Relevant Stimuli

Abstract: This study examined heart rate, finger pulse volume, and skin conductance responses in subjects conditioned to fear-relevant (snakes and spiders) and fear-irrelevant (flowers and mushrooms) slide stimuli by an electric shock unconditioned stimulus. A differential conditioning paradigm with an interstimulus interval of 8 sec was used. There were 4 habituation, 8 acquisition, and 20 extinction trials with each of the two cues. The results demonstrated reliable acquisition for finger pulse volume and skin conductance responses, with superior resistance to extinction for the fear-relevant conditioned stimuli. The heart rate data showed no differentiation between reinforced and nonreinforced cues during acquisition and extinction, and no effect of fear-relevance. This discrepancy between skin conductance and finger pulse volume responses, on the one hand, and heart rate, on the other, was interpreted as due to differences in innervation, with the former measures mainly reflecting sympathetic and the latter parasympathetic effects.

Intravital and electron microscopic study of bradykinin‐induced vascular permeability changes using FITC‐dextran as a tracer

Abstract: Fluorescein-labelled dextran (FITC-dextran) of molecular weight 145,000 was used to study vascular permeability to macromolecules by intravital and electron microscopy. Anaesthetised hamsters prepared for intravital observation of the cheek pouch microvasculature were given an intravenous injection of FITC-dextran. Leakage of macromolecules was induced by topical application of bradykinin to the cheek pouch microvasculature and observed in fluorescent light. Leakages occurred only from postcapillary venules of a diameter well below 50 micrometer. The cheek pouch preparation was rapidly fixed by immersion and samples of tissue with intravitally identified leakages of FITC-dextran were studied by electron microscopy. FITC-dextran appeared as black precipitates in the vascular lumen and also outside the lumen in bradykinin-treated animals. In most animal; gaps were found between endothelial cells and these gaps contained dextran precipitates. The results support much other evidence that bradykinin induces macromolecular leakage by opening gaps between endothelial cells in postcapillary venules.