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Biomedical subjects

K Andersson

Publications and source records attributed to K Andersson.

At least 361 records · Page 20Linked to original sources
PubMed1975

The relationship between molecular size and electrphoretic mobility in agarose gels as determined from a single population of growing RNA molecules.

Growing RNA molecules obtained from a defined transcription unit, the 75 S RNA transcription unit in Balbiani ring 2 of Chironomus tentans, have been analysed by electrophoresis in agarose. This set of RNA molecules forms a broad distribution of molecules with sizes ranging from very small up to the final product of giant size corresponding to 75 S RNA. The relative molecular weights along the migration path were calculated from a simple activity relationship derived from the expected distribution properties of a single population of growing RNA molecules. It was concluded that there is a linear relationship between the molecular weight and the logarithm for the mobility.

Animals↗
PubMed1975

Effects of cigarette smoking on learning and retention.

Verbal rote learning was studied on 10 habitual smokers in a smoking and non-smoking session. Smoking induced a significant decrease in the number of correct responses on the learning task as compared to non-smoking values. The imparied learning coincided in time by an increased arousal as measured by heart rate. A test of recall 45 min after the end of the learning period, when the pre-smoking arousal level had been restored, showed that retention was better in the smoking condition than in the non-smoking condition. The results were interpreted in terms of Walker's theory (1958) postulating a relationship between arousal level and consolidation of memory.

Adult↗
PubMed1975

Immediate effects of cigarette smoking as related to different smoking habits.

A questionnaire concerning interactions between the need to smoke and the external situation was used to select 8 "low-arousal smokers" and 8 "high-arousal amokers." The former were smokers who generally experienced their strongest need to smoke in low-arousal situations, characterized by e.g., monotony or boredom, while the latter experienced their strongest need to smoke in high-arousal situations, characterized by, e.g., anxiety or excitement. Members of each group were examined under smoking and nonsmoking conditions in a low-arousal situation, i.e., performing a vigilance-type sensorimotor task, and in a high-arousal situation, i.e., performing a complex sensorimotor task. It was shown that the two groups reacted differently to smoking in the two situations. In low-arousal smokers performance and general well-being were favourably affected by smoking in the low-arousal situation only. Conversely, performance and well-bing of the high-arousal smokers were enhanced by smoking in the high-arousal situation only.

Adult↗
PubMed1975

Silastic arthroplasty of the metacarpophalangeal joints in rheumatoid arthritis.

Fifty rheumatodi patients (fifty hands) had Silastic joint implants in 144 metacarpophalangeal joints. Average follow-up time was 2.5 years (maximum 3.5 and minimum 1.5). At clinical examination, gross power, range of motion, lessening of ulnar deviation, relief of pain, and appearance were determined. The results were correlated with preoperative indications. Postoperatively, there was no significant gain in gross power. The range of motion was somewhat increased and the lessening of ulnar deviation was marked. Relief of pain was achieved. Complications included fracture of four of the 144 implants, one infection, and six cases of tendon adhesions.

Activities of Daily Living↗
PubMed1975

The relationship between some psychological factors and the outcome of medical rehabilitation.

The purpose of the present study was to investigate the relationship between some psychological factors and the outcome or rehabilitation. The subjects were 70 patients at the Department of Rehabilitation Medicine, Central Hospital, Jönköping. The mean age was 45.8 years (range 20-66). They were subjected to an intelligence test, a personality inventory and a perceptual test. The outcome of the rehabilitation was measured with ratings by the staff members and by the patient himself. Positive factors for a sucessful rehabilitation was low age, good education, good intelligence and a high degree of dominance (i.e. self-confidence, ego-strength, a need to attract attention and no guilt feelings). A negative personality factor was passive dependence (i.e. lack of independence, application for assistance and dependence on other people). The most pronounced factor was field dependence-independence. The field independent subjects reached a more sucessful rehabilitation than the field dependent. This may be due to the fact that a field independent person makes his perceptual judgements according to inner frames of reference and directs and organizes his experiences more than does the field dependent. He also uses more complex and more specialized defences and experiences his own body in an analytical fashion which results in an articulated body concept and a well-developed sense of separate identity.

Adult↗
PubMedDate not supplied

Exploring buffer space for molecular interactions.

The interaction of two molecules binding to each other is described by two rate parameters, the association rate parameter k(a) and the dissociation rate parameter k(d). Under standardized conditions these kinetic parameters can be determined by analysis of their interaction in an affinity-based biosensor system, such as BIACORE(R) 3000. The association rate describes the collision frequency and the attraction between two molecules and the dissociation rate describes the stability of the molecular complex. By comparing the affinity of different molecules (calculated as the quotient of the association rate parameter and the dissociation rate parameter), an estimation of specificity can be obtained. For dissociation, two different aspects can be considered-the practical aspect, where one is interested in separating the two molecules, and the informative aspect, where one is interested in the reasons for the dissociation event. This review focuses on a method that was designed to solve the practical problem of regeneration, but eventually produced a considerable amount of information about the interactions themselves.

Antibodies, Monoclonal↗
PubMedDate not supplied

Predicting the kinetics of peptide-antibody interactions using a multivariate experimental design of sequence and chemical space.

A multivariate approach involving modifications in peptide sequence and chemical buffer medium was used as an attempt to predict the kinetics of peptide-antibody interactions. Using a BIACORE system the kinetic parameters of the interaction of Fab 57P with 18 peptide analogues of an epitope of tobacco mosaic virus protein were characterized in 20 buffers of various pH values and containing different chemical additives (NaCl, urea, EDTA, KSCN and DMSO). For multivariate peptide design, three amino acid positions were selected because their modification was known to moderately affect binding, without abolishing it entirely. Predictive mathematical models were developed which related kinetic parameters (k(a) or k(d)) measured in standard buffer to the amino acid sequence of the antigen. ZZ-scales and a helix-forming-tendency (HFT) scale were used as descriptors of the physico-chemical properties of amino acids in the peptide antigen. These mathematical models had good predictive power (Q(2) = 0.49 for k(a), Q(2) = 0.73 for k(d)). For the non-essential residues under study, HFT and charge were found to be the most important factors that influenced the activity. Experiments in 19 buffers were performed to assess the sensitivity of the interactions to buffer composition. The presence of urea, DMSO and NaCl in the buffer influenced binding properties, while change in pH and the presence of EDTA and KSCN had no effect. The chemical sensitivity fingerprints were different for the various peptides. The results indicate that multivariate experimental design and mathematical modeling can be applied to the prediction of interaction kinetics.

Amino Acid Sequence↗
PubMedDate not supplied

Micropreparative ion exchange high performance liquid chromatography: applications to microsequence analysis.

Data on the characterization of anion and cation micropreparative (50 x 1.6 mm i.d.) HPLC columns is presented. It is shown how subnanomole quantities of protein can be efficiently recovered from such columns, rendering them compatible for use in multidimensional chromatographic strategies for the purification of trace biological samples. By selection of appropriate solvent systems (e.g., buffer-free sodium chloride solutions), the small eluant peak volumes can be loaded directly onto the gas phase sequencer, and N-terminal sequence data obtained. The potential of the technique is illustrated for the purification of a GTPase activating protein (GAP-3).

Amino Acid Sequence↗
PubMedDate not supplied

Towards a two-dimensional database of common human proteins.

A protein pattern of common human proteins was constructed by comparing the two-dimensional gel electrophoresis (2-DE) protein patterns from five cell lines of different germ layers. Total cell lysate and the isolated and purified nuclei of each cell line were separated by parallel electrophoresis runs in a multiple casting system of highest reproducibility. The computerized image analysis of the digitized 2-DE gels revealed a master protein pattern for each cell line. By comparison of all master protein patterns a 2-DE protein map of only common human proteins was constructed as a basis for a new 2-DE database. In a first step we have started characterizing a number of spots by microsequencing, amino acid composition analysis, and mass spectroscopy.

Blood Proteins↗