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Biomedical subjects

G Johansson

Publications and source records attributed to G Johansson.

At least 127 records · Page 7Linked to original sources
PubMed1996

Effect of potential binding site overlap to binding of cellulase to cellulose: a two-dimensional simulation.

A computer simulation model for the binding of ligands to a totally anisotropic surface (infinite two-dimensional square lattice) with overlapping binding sites has been developed. The validity of the simulation has been proven by comparison with cases where the correct results are known. The simulation of kinetics shows that when the lattice is close to saturation, the true equilibrium state is reached extremely slowly due to a lot of rearranging of the ligands on the lattice. Based on these findings, the terms 'apparent saturation' and 'apparent maximum coverage' have been introduced and defined. The largest discrepancies between 'apparent maximum coverage' and the theoretically predicted value were observed for ligands of large size and/or irregular shape. As an example, the model has been applied to describe the binding of cellobiohydrolase-I core to Avicel. A formula for calculation of the intrinsic binding constant, maximal binding capacity and specific surface of cellulose from real binding data has been derived.

Adsorption↗
PubMed1996

Body composition and tissue distributions in growth hormone deficient adults before and after growth hormone treatment.

This study examines short and long-term effects of recombinant human growth hormone (rhGH) on body composition and regional tissue distributions by using a multicompartment technique based on computed tomography. Part I includes nine subjects aged 46 +/- 9 years with adult onset GH deficiency who were examined before and in the end of 6 months treatment with rhGH (0.4 U.kg-1.week-1) in a double-blind crossover trial. Part II is an ongoing open trial including seven of the males in part I. They were treated with rhGH (0.25 U.kg-1.week-1) over an additional period of 24 months. Adipose tissue (AT) was reduced by 4.7 kg (p < 0.01) while the muscle plus skin compartment (M) and visceral organs (V) were increased by 2.4 (p < 0.05) and 0.7 kg (p < 0.01), respectively, over 6 months of treatment with a high rhGH dose. A preferential lipid mobilization occurred in the visceral and subcutaneous trunk depots resulting in a changed AT distribution. Muscles of legs and arms increased while the increase of trunk muscles did not reach significance. The body composition changes were maintained over 2 years additional treatment. The preferential loss in visceral AT was further pronounced while other changes in tissue distributions observed during the first 6 months tended to be reversed on the lower rhGH dosage. It is concluded that growth hormone has profound and discordant effects on AT, M and V and with associated changes in tissue distributions. The beneficial effects on body composition seen in short-term treatment is preserved throughout an additional 24 months period of treatment.

Adipose Tissue↗
PubMed1996

Young adults' views on dental care--a qualitative analysis.

The aim of the present study was to determine young adults' views on dental care. The gathered data were gleaned from interviews and analysed in accordance with comparative method. It was possible to discern the views from two perspectives: the patients' opinions regarding costs in relation to given functions within dental care, and the attitudes to given functions in dental care per se. Costs for information and service were deemed questionable, whereas the costs for examination and treatment were accepted. The patients' stance was active with respect to information and treatment, whereas a greater degree of passivity prevailed within the areas of examination and service. According to this report, maintaining cheap dental care rates was deemed important. The patients questioned having to pay for information perceived as irrelevant to dental care. They expressed a hidden wish to assume an active role while being given more information, and to exercise greater influence with reference to own dental care, but were not in the habit of stating their views to dental staff. Thus, continuous patient satisfaction studies are vital in order to meet this group's needs. One suggestion for further research is to study how young adults regard dental care based on the theory presented.

Adult↗
PubMed1996

Alzheimer's disease, oral function and nutritional status.

OBJECTIVES: To study differences in nutritional, dental status and oral function between institutionalised patients with Alzheimer's disease and cognitively healthy elderly people living in the community. DESIGN: Comparison was made between two groups. Alzheimer's disease sufferers and healthy controls, using established criteria for anthropometric, mental and dental state. SETTING: An institution and residential area in Stockholm, Sweden. SUBJECTS: Forty patients with Alzheimer's disease living in a nursing home and 40 age- and gender-matched control subjects living independently. INTERVENTION: Dental status and anthropometric variables. RESULTS: Overnutrition was less frequent among the demented than the controls and more demented were undernourished. Dental status was similar in the two groups with few edentulous subjects but only 2 of 7 edentulous subjects with Alzheimer's disease wore dentures. Having natural teeth and many functional oral zones is important for food consistency choice, but not for nutritional status. In the Alzheimer group, the stage of dementia has a strong association to the ability to eat unaided and an association with dental status. CONCLUSION: There are differences in nutritional status between Alzheimer's patients in institutions and cognitively healthy elderly living at home. The choice of food consistency is correlated to dental status but nutritional status is not shown to be influenced by dental status. However, the ability to eat unaided is strongly correlated to cognitive status.

Aged↗
PubMed1996

Otoneurologic and audiologic findings in fibromyalgia.

Patients with fibromyalgia were studied with otoneurological and audiological tests. Altogether 168 patients (141 women) participated. Vertigo/dizziness was reported by 72% of the patients. Sensorineural hearing loss was found in 15% of the cases. Auditory brainstem responses (ABR) and oculomotor tests were applied, and statistical comparisons between patients and controls were performed. Significant differences were found for the absolute latency of wave V and for the I-V and III-V interpeak latencies, indicating brainstem dysfunction. Abnormal ABR recordings were found in 30% of the cases. In the oculomotor study the mean velocity gain for the smooth pursuits and the mean saccadic latency were significantly different between patients and controls. Abnormal saccades were seen in 28% and pathological smooth pursuit eye movements in 58% of the patients. Electronystagmography was pathological in 45% of the cases. The findings indicate that CNS dysfunction frequently occurs in patients with fibromyalgia, although proprioceptive disturbances might also explain some of the abnormalities observed.

Adult↗
PubMed1995

Cloning and characterization of a cDNA encoding a cellobiose dehydrogenase from the white rot fungus Phanerochaete chrysosporium.

The cDNA of cellobiose dehydrogenase (CDH) from Phanerochaete chrysosporium has been cloned and sequenced. The 5' end was obtained by PCR amplification. The cDNA contains 2310 translated bases excluding the poly(A) tail. The deduced mature protein contains 770 amino acid residues and is preceded by a 18 residue long signal peptide. The regions of the amino acid sequence corresponding to the heme and FAD domains of CDH were identified as well as the nucleotide-binding motif, the disulfide pairing and a methionine residue chelating the heme iron. No homologous sequences were found for the heme domain, however, the FAD domain appears to be distantly related to the GMC oxidoreductase family.

Amino Acid Sequence↗
PubMed1995

3-Heteroaryl-substituted quinuclidin-3-ol and quinuclidin-2-ene derivatives as muscarinic antagonists. Synthesis and structure-activity relationships.

A number of 3-heteroaryl-substituted quinuclidin-3-ol and quinuclidin-2-ene derivatives have been prepared and evaluated for muscarinic and antimuscarinic properties. The affinities of the new compounds (13, 14, 16-32, and 36-52a,b) were tested in homogenates of cerebral cortex, heart, parotid gland, and urinary bladder from guinea pigs using (-)-[3H]-3-quinuclidinyl benzilate [(-)-[3H]QNB] as the radioligand and in a functional assay using isolated guinea pig urinary bladder. The present compounds behaved as competitive muscarinic antagonists in the urinary bladder. The highest receptor binding affinity, Ki (cortex) = 9.6 nM, was observed for 3-(2-benzofuranyl)quinuclidin-2-ene (31). The corresponding 3-benzofuranyl (36) and 3-benzothienyl (37) homologues had about 3.5-fold lower affinity for cortical muscarinic receptors. All quinuclidin-3-ol derivatives (14 and 16-25) had lower binding affinities for the different muscarinic receptor subtypes than the corresponding quinuclidin-2-ene analogues when examined in the various tissue homogenates. In general, the new compounds showed low subtype selectivity. The structure-affinity relationships are discussed in terms of differences in proton basicity of the azabicyclic nitrogen and differences in geometric, conformational, and/or electronic properties of the compounds. The cortical antimuscarinic potency is also related to the complementarity of the compounds to the putative binding site of the muscarinic m1 receptor.

Animals↗
PubMed1995

Calculation of the isoelectric points of native proteins with spreading of pKa values.

The isoelectric points (pI) of native proteins are important in several separation techniques. For estimating pI values the net charge of several proteins was calculated versus pH by use of the Henderson-Hasselbalch equation. Amino acid composition, pKa values for amino acid side chains and for the N- and C-terminal groups, and the presence of other charged groups were taken into account. A set of pKa values was chosen for amino acid residues with ionizable side chains. Each particular type of ionizable group was assumed to have pKa values distributed around the chosen value, thereby simulating the situation in proteins and polypeptides. The calculated pI values showed reasonably good agreement with experimental ones for most of 16 native proteins over a wide pH range (3.4-11) when charge contributions of heme groups, sialic acid residues, etc., were taken into account. The calculated pI for the human red cell glucose transporter (Glut1) with one sialic acid residue was decreased from 8.8 to 8.5 by introducing pKa value spreading and became consistent with the experimental pI value of 8.4 +/- 0.05 at 15 degrees C determined in the presence of 6 M urea. The pI of the native Glut1 was lower, 8.0 +/- 0.1, at 22 degrees C. In general, the pI values for native proteins are affected by the three-dimensional structure of the proteins, which causes greater differences between calculated and experimental pI values than in the case of polypeptides for which pI values are determined in the presence of urea.

Amino Acids↗
PubMed1995

High-affinity binding of two molecules of cysteine proteinases to low-molecular-weight kininogen.

Human low-molecular-weight kininogen (LK) was shown by fluorescence titration to bind two molecules of cathepsins L and S and papain with high affinity. By contrast, binding of a second molecule of cathepsin H was much weaker. The 2:1 binding stoichiometry was confirmed by titration monitored by loss of enzyme activity and by sedimentation velocity experiments. The kinetics of binding of cathepsins L and S and papain showed the two proteinase binding sites to have association rate constants kass,1 = 10.7-24.5 x 10(6) M-1 s-1 and kass,2 = 0.83-1.4 x 10(6) M-1 s-1. Comparison of these kinetic constants with previous data for intact LK and its separated domains indicate that the faster-binding site is also the tighter-binding site and is present on domain 3, whereas the slower-binding, lower-affinity site is on domain 2. These results also indicate that there is no appreciable steric hindrance for the binding of proteinases between the two binding sites or from the kininogen light chain.

Amino Acid Sequence↗
PubMed1995

Cell-surface charge and cell-surface hydrophobicity of collagen-binding Aeromonas and Vibrio strains.

Partitioning in aqueous polymer two-phase systems of polyethylene glycol and dextran was used to detect and compare cell-surface charge and cell-surface hydrophobicity of Aeromonas hydrophila, A. caviae, A. sobria, Vibrio cholerae, and V. anguillarum strains. These strains have cell-surface components that bound either native or thermally denatured type I collagen (i.e., a mixture of the alpha1+alpha2 chains) and gelatin immobilized on latex beads. Our goals were: (1) to compare the possible relationship between the cell-surface charge/hydrophobicity and binding to collagen and (2) to evaluate the influence of the culture media on the expression of surface properties. There was no apparent relationship between cell-surface charge, cell-surface hydrophobicity, and binding to collagen. The expression of surface properties was dependent on the culture media. There was no relationship between binding to immobilized collagen and binding to soluble 125I-labeled collagen. Particle-agglutination reactivity differed when using various collagen-coated microbead preparations. There were general differences in the particle-agglutination reactivity when collagen-coated latex beads were prepared using different coating procedures. The negative charge and hydrophobicity of the various collagen-coated microbead preparations were also studied by partitioning in the two-phase system of polyethylene glycol and dextran. Under these conditions, the alpha1+alpha2 collagen-chain mixture covalently immobilized on carboxy-modified latex beads was less hydrophobic and negatively charged than gelatin and native collagen immobilized on the same kind of latex beads. For latex beads passively coated with collagen preparations, the alpha1+alpha2 collagen-chain mixture was more hydrophobic than gelatin and native collagen. We suggest that for screening collagen-binding among Vibrio and Aeromonas strains, a reliable and sensitive particle-agglutination assay should consider the collagen preparation and the coating procedure for the immobilization of collagen onto the latex beads. In this regard, carboxy-modified latex beads coated with an alpha1+alpha2 collagen-chain mixture gave the best results.

Aeromonas↗
PubMed1995

Quinuclidin-2-ene-based muscarinic antagonists.

A series of achiral 3-heteroaryl substituted quinuclidin-2-ene derivatives and related compounds have been synthesized by facile methods. The compounds were evaluated for muscarinic and antimuscarinic properties in receptor binding studies using (-)-[3H]-QNB as the radioligand and in a functional assay using isolated guinea pig urinary bladder. 3-(2-Benzofuranyl)-quinuclidin-2-ene (15) displayed the highest M1-receptor affinity in the present series (Ki = 9.6 nM).

Animals↗
PubMed1995

Ruptured thoracic aortic aneurysms: a study of incidence and mortality rates.

PURPOSE: The purpose of this study was to determine the incidence and mortality rate of ruptured thoracic aortic aneurysm (TAA) in a well-defined population. METHODS: Retrospective analysis of complied data from multiple registries in Stockholm, Sweden was performed. RESULTS: Eighty-two and 76 cases were identified from 1980 and 1989, respectively, for an equal incidence of 5 per 100,000. Forty-one percent of the patients were alive on arrival at an emergency hospital, but the overall mortality rate was 97% to 100%. CONCLUSIONS: The mortality rate of ruptured TAA is high. To decrease this high mortality rate, efficient screening methods for the diagnosis of TAA must be worked out, characteristics indicating high risk of rupture must be identified, and efforts should be made to increase the number of operations for ruptured TAA.

Aged↗
PubMed1995

A new method of using gas exchange measurements for the noninvasive determination of cardiac output: clinical experiences in adults following cardiac surgery.

New mathematical algorithms have been applied to a computer controlled closed breathing circuit system for non-invasive measurement of cardiac output (COniv). This system has been described in an animal study. Forty patients were studied 5 and 18 hours after cardiac surgery using the thermodilution technique as the reference (COtd). The variables entered into the algorithms for COniv were oxygen uptake, carbon dioxide elimination, end-tidal carbon dioxide partial pressure, tidal volume and arterial oxygen saturation. Mixed venous carbon dioxide partial pressure was obtained from an automatically implemented short rebreathing manoeuvre. Pulmonary perfusion was calculated by a modified Fick equation for carbon dioxide and the shunt flow added to obtain COniv. During mechanical ventilation, there was a good agreement between COtd and COniv (r = 0.8). The bias was -0.14 l/min and the precision was 0.77 l/min. The reproducibility of COniv was 0.03 l/min and for COtd -0.03 l/min with a standard deviation of the difference being 0.35 l/min for COniv and 0.31 l/min for COtd. In awake, but sedated extubated patients, the method proved unsatisfactory on account for uneven tidal volumes and difficulties with leakage around the mouth piece. We conclude that this new technique provides reliable and reproducible measures of cardiac output in sedated, ventilated patients.

Adult↗
PubMed1995

Cerebral dysfunction in fibromyalgia: evidence from regional cerebral blood flow measurements, otoneurological tests and cerebrospinal fluid analysis.

Measurements of regional cerebral blood flow (rCBF), analysis of cerebrospinal fluid, auditory brain stem responses (ABR) and oculomotor tests were performed in 19 patients with fibromyalgia. The results from the rCBF measurements showed a normal flow level with slight but significant focal flow decreases in dorsolateral frontal cortical areas of both hemispheres. The ABR results showed signs of dysfunction at least at the brain stem level and the oculomotor tests showed high frequency of pathology. The cerebrospinal fluid analysis showed discrete changes in the cell differential count. Possible explanations for the involvement of the central nervous system in fibromyalgia are discussed.

Adult↗
PubMed1995

Comparison of some salivary variables between vegetarians and omnivores.

The aim of the study was to compare salivary variables in a group of vegetarians with a group of omnivores. Twenty-nine vegetarians, 19 women and 10 men, mean age 35 yr, and 28 omnivores, 20 women and 8 men, mean age 35 yr, were compared in terms of salivary secretion rate, pH, buffer capacity, mutans streptococci and lactobacilli. The vegetarians had a significantly higher secretion rate, but there were no other significant differences regarding the salivary variables. The difference in secretion rate may have been caused by some lifestyle factor(s) differing between vegetarians and omnivores which probably mainly include nutrient(s), texture and roughness of the food.

Adult↗
PubMed1995

Comparison of the effect of the linseed extract Salinum and a methyl cellulose preparation on the symptoms of dry mouth.

The effect of a linseed extract Salinum and a sodium carboxymethyl cellulose preparation called MAS-84 was compared with regard to its effect on the symptoms of dry mouth. Twenty patients with xerostomia, who had been treated for cancer in the head and neck by radiation were recruited from the clinic for maxillofacial surgery, Malmo University Hospital. Following radiation treatment the salivation was severely reduced. The symptoms of a general feeling of a dry mouth, difficulties in chewing and swallowing, taste disturbances, problems with speech and mouth burning were registered on a subjective verbal rating scale. In addition plaque index and gingival bleeding were determined. The study design was crossover and performed single blind. The experimental period was 7 weeks. The patients were randomly divided into 2 groups. One group used Salinum and the other MAS-84 for 3 weeks. The fourth week was a wash out period and for the next three weeks the patients shifted preparation. Each of the preparations was used ad libitum. Registrations of the various parameters were undertaken on days 0, 7 and 21 of the respective period. At the initial examination all patients reported considerable disturbances from mouth-dryness. These symptoms were reduced in 15 patients during the Salinum period and in 9 during the MAS-84 period. The relief was significantly more pronounced during the use of Salinum compared to that during the use of the methyl cellulose preparation. On day 21 plaque and gingival bleeding were significantly reduced during the Salinum period but not during the MAS-84 period. The results of the present study confirm those of a previous pilot study and indicate that the linseed mucilage significantly reduced the symptoms of dry mouth. This effect increased with increasing time of saliva substitute use. The linseed mucilage Salinum appeared to be a suitable saliva replacement in mouth dry patients.

Aged↗
PubMed1995

Muscle fiber characteristics, capillaries and enzymes in patients with fibromyalgia and controls.

In 11 female patients with Fibromyalgia Syndrome (FS), biopsies from the m. vastus lateralis were analyzed, in order to reveal any possible changes which might explain muscular weakness and fatigue. Nineteen healthy subjects served as a control group. Light microscopy did not show any gross histopathological findings. Fiber composition and fiber areas did not differ between the two groups, except for a greater coefficient of variation of the area of type II A fibers and of the mean fiber area in the FS group. The number of capillaries per square millimeter and also the fiber area in relation to the capillaries, was lower in the FS patients. Analyses of enzymes showed decreased levels of 3-hydroxy-CoA-dehydrogenase and citrate synthase in the patient group. The reduced oxidative enzyme levels and capillarization indicate reduced physical activity, although this does not associate with muscle fiber hypotrophy.

Adult↗