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Biomedical subjects

K Johansson

Publications and source records attributed to K Johansson.

At least 127 records · Page 7Linked to original sources
PubMed1993

Intraduodenal infusion of a water-based levodopa dispersion for optimisation of the therapeutic effect in severe Parkinson's disease.

Motor performance of five patients with advanced Parkinson's disease was investigated during their optimum oral therapy (conventional tablets and/or depot capsules) and during a continuous duodenal infusion of levodopa. Due to the low water solubility of the drug, conventional tablets of levodopa+carbidopa (Sinemet) were milled and dispersed in a 1.8% aqueous methylcellulose solution. The dispersion was delivered nasoduodenally by a portable pump. The effect of levodopa in the two dosing regimens was estimated optico-electronically every 15 min and was also evaluated from videorecordings every 30 min and plasma levels of levodopa was regularly measured. Each dosage regimen the was studied twice, at a 2-4 day interval. Duodenal infusion improved motor function in all five patients and the fluctuations were reduced when compared to the oral therapy. Variation in plasma levodopa concentrations was 3-10 fold during oral therapy, while during the infusion a stable concentration was obtained. The therapeutic concentration varied from 0.3-3 ml-1 between patients. The relative bioavailability of levodopa in the solid preparation compared to the dispersion was in all patients 100%. Our results encourage further development of a duodenal infusion system with a levodopa dispersion for clinical use in parkinsonian patients who show severe fluctuation.

Administration, Oral↗
PubMed1993

Screening of amyloid precursor protein gene mutation (APP 717 Val-->Ile) in Swedish families with Alzheimer's disease.

Screening for the APP 717 Val-->Ile mutation in the amyloid precursor protein (APP) gene in 34 Swedish families with familial Alzheimer's disease (FAD), 16 sporadic cases of Alzheimer's disease and five patients with Down's syndrome (DS) failed to identify further cases of the mutation. These results suggests that the mutation is rare among Swedish families with Alzheimer's disease. In addition, we summarize present reports of the frequency of the mutation.

Aged↗
PubMed1993

A reagentless amperometric biosensor for alcohol detection in column liquid chromatography based on co-immobilized peroxidase and alcohol oxidase in carbon paste.

A reagentless carbon paste electrode chemically modified with covalently bound alcohol oxidase and horse-radish peroxidase was examined as a selective sensor in flow injection and column liquid chromatography. A combination of carbodiimide, glutaraldehyde, and polyethyleneimine was used for immobilizing the enzymes in the paste. The surface of the electrodes was protected by first forming a layer of electropolymerized ortho-phenylenediamine followed by deposition of a cation exchange membrane (Eastman AQ 29D). The electrodes were used for detection of hydrogen peroxide, methanol, ethanol, propanol, isopropanol, and butanol. Preliminary investigations of the use of this sensor for bioprocess control are reported.

Alcohol Oxidoreductases↗
PubMed1993

Enzyme replacement therapy of infantile Gaucher disease.

We report our experience from enzyme infusion therapy in a girl with infantile (type 2) Gaucher disease. When treatment was started at 5.5 months of age, she already had severe neurological symptoms. After three months of treatment, the hematological parameters and blood glucosylceramide levels were normalized. The spleen and liver sizes were reduced and the neurological deterioration seemed to have stopped. There was, however, no improvement of her existing neurological symptoms. Her lung function deteriorated because of constant aspirations. Enzyme treatment was stopped after seven months. We cannot recommend enzyme substitution therapy when severe neurological signs have already emerged.

Female↗
PubMed1993

Nitric oxide synthase in pig lower urinary tract: immunohistochemistry, NADPH diaphorase histochemistry and functional effects.

1. The distribution and colocalization of nitric oxide synthase (NOS)-like immunoreactivity and NADPH diaphorase activity in the pig lower urinary tract were investigated by immunohistochemical and histochemical staining techniques. Functional in vitro studies were performed to correlate the presence of NOS-immunoreactivity/NADPH diaphorase staining with smooth muscle responses involving the L-arginine/nitric oxide (NO) pathway. 2. NOS-immunoreactivity and NADPH diaphorase activity were expressed in nerve trunks and fine nerve fibres in and/or around muscular bundles in the detrusor, trigone and urethra. Thin nerve fibres that dispersed within the muscle bundles were mainly found in the urethral/trigonal area, whereas such fibres were less common in the detrusor. 3. Almost all neuronal structures that were NOS-immunolabeled were also stained for NADPH diaphorase. In contrast, the urothelium, which was intensively stained by the NADPH diaphorase technique, remained unstained by immunohistochemistry. 4. Electrical field stimulation of pig isolated trigonal and urethral preparations induced relaxations, which were inhibited by tetrodotoxin (1 microM) and NG-nitro-L-arginine (L-NOARG, 10 microM). 5. L-Arginine (1 mM), but not D-arginine, inhibited (25-30%) electrically evoked detrusor contractions. This inhibition was reversed by L-NOARG (0.1 mM). L-Arginine did not inhibit detrusor contractions in the presence of scopolamine (1 microM) and had no direct smooth muscle effects per se. 6. Acetylcholine (1 nM-10 microM) caused concentration-dependent relaxations of noradrenaline-induced contractions in pig vesical arteries. Removal of the endothelium practically abolished the acetylcholine-induced relaxation. Pretreatment with L-NOARG (0.1 mM and 0.3 mM) caused a rightward shift of the concentration-response curves to acetylcholine, but the maximal relaxation obtained was significantly reduced (to 65 +/- 12%; n = 6; P < 0.05) only at 0.3 mM L-NOARG. 7. In vessel segments contracted with K+ (60 mM), acetylcholine induced concentration-dependent relaxations. When the vessels were incubated with 0.3 mM L-NOARG and then contracted with K+ (60 mM) all relaxant responses to acetylcholine were abolished. 8. The presence of NO synthesizing enzyme in nerve fibres and the pharmacological evidence for NO-mediated relaxation of the trigone and urethra suggest that NO or a NO-related substance may have a role in inhibitory neurotransmission in these regions. In the detrusor, the presence of NO-synthesizing enzyme in nerves can be demonstrated, but its functional importance is unclear. NO, as well as other endothelium-derived factors seem to be involved in the endothelium-dependent acetylcholine-induced relaxation of pig vesical arteries.

Acetylcholine↗
PubMed1993

Can sensory stimulation improve the functional outcome in stroke patients?

After obtaining informed consent, we randomized 78 patients with severe hemiparesis of the left or right side within 10 days of stroke onset: 40 to a control group receiving daily physiotherapy and occupational therapy, and 38 to a group that, in addition, we treated with sensory stimulation (acupuncture) twice a week for 10 weeks. The median age was 76 years for both groups. Motor function, balance, and ADL (Barthel's Index) were assessed before the start of treatment and at 1 and 3 months after stroke onset; ADL was also assessed after 12 months. We assessed the quality of life (QL) using the Nottingham Health Profile 3, 6, and 12 months after stroke onset. Patients given sensory stimulation recovered faster and to a larger extent than the controls, with a significant difference for balance, mobility, ADL, QL, and days spent at hospitals/nursing homes. Whether acupuncture per se is responsible for the differences requires further study.

Activities of Daily Living↗
PubMed1993

Selection for litter size, body weight, and pelt quality in mink (Mustela vison): experimental design and direct response of each trait.

In a five-generation selection experiment, separate lines of mink (Mustela vison) were subjected to selection for improved litter size at 3 wk (F line), BW in September (BS line), and underfur density (P line), and combined selection for litter size and BW (I line). Underfur density was subjectively judged on live animals. One unselected line served as a control (C line). Significant changes were achieved in each trait: litter size in the last generation was 5.3 in the F line vs 3.7 in the C line; September weight in males was 2,254 g in the BS line vs 1,979 g in the C line, and the underfur density score, graded using a 5-point scale, was 4.1 in the P line vs 2.9 in the C line. In the combined line (I line) litter size was only slightly improved, whereas BW was substantially increased (male mean = 2,194 g). A univariate animal model was used to predict genetic values and to estimate variance components with a REML procedure. Heritability estimates were .14 +/- .09 for litter size, .39 +/- .06 for September weight, and .21 +/- .06 for underfur density. It was confirmed that the reproductive performance of heavy of fat animals was poor. Responses were higher than predicted when selecting for September weight and underfur density. In the last generation the average breeding values, relative to the base generation, were +.8 kits for litter size (F line), +365 g for male September weight (BS line), and +1 point for underfur density (P line). The study suggests that negative maternal effects on litter size may exist in mink.

Animals↗
PubMed1993

Associations between major histocompatibility complex genes and production traits in White Leghorns.

The frequency of the MHC haplotype B15 had been found in a previous study to be more than two times higher in a White Leghorn line selected for high egg production compared with the unselected control strain. To further evaluate these findings, matings were performed between chickens with the same heterozygous B genotypes, being combinations of the most frequent haplotypes, i.e., B15, B19, and B21. In total, more than 1,300 observations from two generations were analyzed. In each generation, approximately one half of the chickens were derived from the line selected for total egg mass, the other half from the control strain. The MHC genotypes were determined serologically. Additive and dominance effects of B haplotypes on production traits were analyzed using an individual animal model. The estimation of genotypic values, together with the analysis of gene substitution effects, showed that the B15 haplotype was associated with early sexual maturity and low egg production during the late production period, i.e., between 43 and 63 wk of age, whereas B19 was associated with later onset of sexual maturity. The association of B15 with early sexual maturity would thus explain the high frequency of the B15 haplotype previously observed in a line selected for high early egg production. No dominance effect of the B system was observed for any of the traits, suggesting that the present results were due predominantly to additive gene effects.

Animals↗
PubMed1993

Morphological response of the peritoneum and spleen to intraperitoneal biomaterials.

The present study was performed to evaluate the morphological response of the peritoneum and spleen to biomaterials. Silicone elastomer, knitted dacron or rubber was implanted, respectively, into a rat's peritoneal cavity and the morphology of the peritoneum and spleen was studied at 4 hours and on the 1st, 4th, 7th and 21st day after surgery. The morphological changes were identical among groups with different implanted materials. After intraperitoneal implantation of biomaterials from 4 hours and on, an infiltration of inflammatory cells was found in the slackened edematous superficial part of the peritoneum. Also noted in the spleen were stasis, vessel dilatation and fibrin deposition. With the help of scanning electron microscopy, a marked denudation and separation of the mesothelial cells, with infiltration of inflammatory cells, were observed. Peripheral leucocytes significantly increased in number one day after intraperitoneal implantation. Three weeks after intraperitoneal implantation, the materials were completely encapsulated and the morphological aberration of the peritoneum and spleen disappeared. The findings reveal the consequence and the resolution of the host-biomaterial interaction, which could contribute to the explanation of various pathophysiological alterations, including the translocation of enteric bacteria and the development of infectious complications after intraperitoneal biomaterial implantation.

Animals↗
PubMed1992

The gene for Best's macular dystrophy is located at 11q13 in a Swedish family.

A large Swedish family with more than 250 cases of Best's macular dystrophy has been clinically and genetically studied. The gene was traced to a couple born in central Sweden in the 17th century. Highly significant evidence for genetic linkage to DNA markers on chromosome 11q13 was detected. A lod score of 15.12 was obtained at recombination fraction 0.01 with DNA marker INT2 (also called FGF3). The retinally expressed gene ROM1, which maps to the same chromosomal region is a candidate for this genetic disease.

Chromosomes, Human, Pair 11↗
PubMed1992

Estimation of direct and correlated responses to selection using univariate animal models.

Analytic results obtained using simple models show that estimates of selection response of univariate experiments using animal models are completely dependent on the heritability used as prior when fixed effects are nested within generations, and both on the prior and on the true heritability parameter when fixed effects overlap across generations. Univariate animal model estimators of correlated changes of a trait not selected directly are usually biased. The absolute value of the estimate of the correlated response is smaller than the true value when the traits are only genetically correlated and larger than the expected value of zero when they are only environmentally correlated. The validity of the results derived from the analysis of simple models is confirmed using computer simulations, which illustrate the magnitude of the bias. It is emphasized that use of univariate animal models to estimate response in breeding programs whose breeding objectives include several correlated traits may lead to erroneous conclusions.

Analysis of Variance↗
PubMed1992

Piezoelectricity in dental materials, a conceivable cause of postrestorative sensitivity.

With the increased use of tooth-colored posterior inlays reports of postrestorative sensitivity have also increased. One of the symptoms the patients complain of is a sharp pain when the inlays are loaded through chewing and biting. Many explanations for the causes of dissimilar types of postrestorative sensitivity have been offered, but one conceivable explanation that has not hitherto been studied is the direct piezoelectric effect in dental materials. Direct piezoelectric effect means that when certain anisotropic crystals are mechanically loaded, a charge is generated on the surface. The aim of the present study was to examine whether this physical phenomenon occurs in certain materials intended for dental use. Specimens of four different dental ceramics and one indirect composite resin for inlays were mechanically loaded with various forces, and the current was directly recorded. Currents of up to 0.9 microA with a pulse duraton of 0.4 msec were extracted, and it cannot be excluded that the piezoelectric phenomenon and related properties may cause postrestorative sensitivity. This has to be taken into consideration when posterior inlays of the types concerned are used.

Acrylic Resins↗
PubMed1991

Rapid detection of type A influenza viruses with monoclonal antibodies to the M protein (M1) by enzyme-linked immunosorbent assay and time-resolved fluoroimmunoassay.

Monoclonal antibodies (MAbs) to the M protein (M1) were used in the development of direct detection systems for type A influenza viruses in clinical specimens. Optimal detection by an enzyme-linked immunosorbent assay was achieved when MAbs were used as capture antibodies and rabbit polyclonal antibodies were used as sandwich antibodies. Detection by the enzyme-linked immunosorbent assay required amplification of the virus. direct detection in clinical specimens (nasopharyngeal aspirates) was accomplished when MAbs recognizing two distinct antigenic sites of M1 were used in a time-resolved fluoroimmunoassay. Type A influenza viruses could be detected equally well in specimens obtained during epidemics of both H3N2 and H1N1 influenza viruses.

Antibodies, Monoclonal↗
PubMed1991

Contrasting subjective judgement and objective tests in the hearing-impaired.

The Hearing Performance Inventory (HPI, Giolas et al., 1979) was used to measure 21 moderately hearing-impaired persons' subjectively experienced problems in everyday listening. The HPI rating data show that the greatest problems are experienced on the dimensions 'understanding speech without visual cues', and 'perceived intensity' of sounds. 'Understanding speech with visual cues' has a high positive correlation with both 'social situation' and 'work situation' dimensions, whereas 'understanding speech without visual cues' correlates with 'social' and 'personal situation'. The correlations between the HPI and actual performance in the speechreading tests, and between the HPI and cognitive abilities that were assumed to be critical for speechreading ability, were also examined. It was found that vocabulary size, highly intercorrelated with guessing, was important to the 'social situation' dimension on the HPI. Guessing also constitutes an important cognitive predictor of speechreading skill. However, none of the HPI dimensions was directly related to objective communicative competence. Given the limitations of speechreading training, the data suggest that vocabulary and social skills should be focused on during communicative training.

Adult↗