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Biomedical subjects

K Johansson

Publications and source records attributed to K Johansson.

At least 73 records · Page 4Linked to original sources
PubMed1998

Cognition as a bridge between signal and dialogue: communication in the hearing impaired and deaf.

This paper is an overview of the research we have carried out at Linköping University on cognitive aspects of visual language processing and related communicative forms. In the first section, a cognitive individual difference perspective on speechreading is introduced. In the second, compensatory perceptual mechanisms are discussed on the basis of behavioral and neurophysiological data. The third section addresses further the issue of perceptual versus cognitive compensation, and the fourth and fifth sections apply a set of cognitive tests based on the concept of working memory for poorly specified language input to data on the successes and failures with cochlear implants, tactile aids and hearing aids.

Cognition↗
PubMed1998

Long-term intraduodenal infusion of a water based levodopa-carbidopa dispersion in very advanced Parkinson's disease.

OBJECTIVE: To evaluate the effects of continuous duodenal infusion of levodopa over time on the disabling fluctuations in motor performance in advanced parkinsonian patients. It has earlier been demonstrated that these fluctuations can be reduced by keeping the plasma concentration of levodopa constant. MATERIAL AND METHODS: In view of the low water solubility of levodopa a stable dispersion of the drug was developed and used for continuous intraduodenal infusion in patients with advanced Parkinson's disease. Nine patients were evaluated with respect to an optimal oral treatment, during nasoduodenal infusion by a portable pump and then followed for 6 months to 2 1/2 years when treated via transabdominal infusion. Upon each test occasion, over 2 non-consecutive days, objective movement analysis by means of an opto-electronic system was applied every 15-20 min and video recordings performed twice every h. On several test occasions plasma levodopa concentrations were analysed every 15 min. RESULTS: The patients showed improvement and decreased variance of their motor function. In the 2 patients followed over a period of 2 1/2 years levodopa plasma concentration showed reduced fluctuations on infusion and the levodopa consumption as well as mean levodopa plasma concentration decreased. CONCLUSION: Continuous duodenal infusion of levodopa is an alternative treatment strategy for patients with advanced Parkinson's disease when conventional therapy has failed.

Activities of Daily Living↗
PubMed1998

Comparisons of DNA-mediated immunization procedures directed against surface glycoproteins of human immunodeficiency virus type-1 and hepatitis B virus.

DNA vaccination methods were compared to examine the in vivo expression of HIV-1 gp160 and beta-galactosidase, and the resulting immune response. Beta-galactosidase plasmid showed expression rates of 2-5% of muscle fibers with or without pretreatments using bupivacaine or cardiotoxin facilitators 1 or 5 days earlier, respectively. In contrast, HIV gp160 expression was lower in untreated or bupivacaine-treated muscles, but was improved by pretreatment with cardiotoxin. Equal expression of beta-galactosidase and HIV gp160 was obtained using gene gun delivery to the epidermis. Unlike the i.m. in situ expression of gp160, the anti-HIV antibody response did not improve after muscle pretreatments but depended on the vaccination intervals. Gene gun delivery of pMN160 also resulted in a slow and low titered antibody response. In contrast, a single i.m. injection of plasmid encoding another viral envelope, HBsAg, resulted in earlier seroconversion to high titers without the need for pretreatments or boostings. Intradermal inoculation by gene gun using 100-fold less DNA resulted in the same anti-HBsAg antibody profile only after boostings. In contrast to the differences in antibody responses, a specific CTL response was obtained in all cases. Bupivacaine-treated muscles showed an extreme degree of edema with disruption of connective tissue (endo- and mesomysium) and was not well tolerated (4 of 19 mice died). Cardiotoxin created muscle necrosis and occasional (2 of 20 mice) development of fibrotic muscles. It is concluded that in vivo expression cannot be properly predicted using reporter gene experiments and that the resulting immune response does not follow directly with the expression rate. It is suggested that the antibody response may depend primarily on the nature of the antigen expressed rather than the DNA vaccination method. It is proposed that gene gun or i.m. injection be used without pretreatment in the case of DNA vaccination with plasmid encoding HIV MN gp160.

AIDS Vaccines↗
PubMed1998

A randomized controlled trial of rehabilitation at home after stroke in southwest Stockholm.

BACKGROUND AND PURPOSE: This study describes the methodology, patient outcome, and use of hospital and rehabilitation services at 3 months of a population-based randomized controlled trial. The purpose was to evaluate rehabilitation at home after early supported discharge from the Department of Neurology, Huddinge Hospital, for moderately disabled stroke patients in southwest Stockholm. METHODS: The patients were eligible if they were continent, independent in feeding, had mental function within normal limits, and had impaired motor function and/or aphasia 1 week after stroke. Patients were randomized either to early supported discharge with continuity of rehabilitation at home for 3 to 4 months or to routine rehabilitation service in a hospital, day care, and/or outpatient care. The home rehabilitation team consisted of two physical therapists, two occupational therapists, and one speech therapist; one of the therapists was assigned as case manager for the patient. The rehabilitation program at home emphasized a task- and context-oriented approach. The activities were chosen on the basis of the patient's personal interests. Spouses were offered education and individual counseling. A total of 81 patients were followed up for a minimum of 3 months. Patient outcome was assessed by the Frenchay Social Activity Index, Extended Katz Index, Barthel Index, Lindmark Motor Capacity Assessment, Nine-Hole Peg Test, walking speed over 10 m, reported falls, and subjective dysfunction according to the Sickness Impact Profile. Patient use of hospital and home rehabilitation service and patient satisfaction with care were studied. RESULTS: Overall there were no statistical significant differences in outcome. Multivariate logistic regression analysis suggested a systematic positive effect for the home rehabilitation group in social activity, activities of daily living, motor capacity, manual dexterity, and walking. A considerable difference in resource use during such a 3-month period was seen. A 52% reduction in hospitalization was observed: from 29 days in the routine rehabilitation group to 14 days in the home rehabilitation group. Patient satisfaction was in favor of the latter group. CONCLUSIONS: Early supported discharge with continuity of home rehabilitation services for the majority of moderately disabled stroke patients during the first 3-month period after acute stroke is not less beneficial than routine rehabilitation and can be a rehabilitation service of choice if follow-up at 6 and 12 months confirms the suggested effectiveness and considerable reduction in use of health care.

Activities of Daily Living↗
PubMed1998

A randomized study comparing manual lymph drainage with sequential pneumatic compression for treatment of postoperative arm lymphedema.

We compared manual lymph drainage (MLD) with sequential pneumatic compression (SPC) for treatment of unilateral arm lymphedema in 28 women previously treated for breast cancer. After 2 weeks of therapy with a standard compression sleeve (Part I) with maintenance of a steady arm volume, each patient was randomly assigned to either one of two treatment regimens (Part II). MLD was performed according to the Vodder technique for 45 min/day and SPC was performed with a pressure of 40-60 mmHg for 2 hours/day. Both treatments were carried out for 2 weeks. Arm volume was measured by water displacement. Arm mobility, strength, and subjective assessments were also determined. Lymphedema was reduced by 49 ml (7% reduction) (p = 0.01) in the total group during Part I. During Part II, the MLD group decreased by 75 ml (15% reduction) (p < 0.001) and the SPC group by 28 ml (7% reduction) (p = 0.03). The total group reported a decrease of tension (p = 0.004) and heaviness (p = 0.01) during Part I. During Part II, only the MLD group reported a further decrease of tension (p = 0.01) and heaviness (p = 0.008). MLD and SPC each significantly decreased arm volume but no significant difference was detected between the two treatment methods.

Aged↗
PubMed1997

A novel pathogenic mutation (Leu262Phe) found in the presenilin 1 gene in early-onset Alzheimer's disease.

Several mutations causing early-onset familial Alzheimer's disease (AD) have been detected in the presenilin 1 (PS-1) gene. Pathogenic mutations have also been described in an homologous gene, presenilin 2 (PS-2). In order to screen for mutations in these genes, cDNA samples from early-onset AD cases were analysed, using single strand conformation polymorphism (SSCP) and direct cDNA sequencing. Two missense mutations in the PS-1 gene were detected, a previously unidentified amino acid substitution Leu262Phe and an earlier reported amino acid substitution Glu318Gly. No disease-related mutations were found in the PS-2 gene.

Age of Onset↗
PubMed1997

Morphological and functional evidence against a sensory and sympathetic origin of nitric oxide synthase-containing nerves in the rat lower urinary tract.

To establish which type of nerves (parasympathetic, sympathetic or sensory) produce nitric oxide in the rat lower urinary tract, chemical denervation of primary afferents and sympathetic nerves was carried out by systemic treatment with capsaicin and 6-hydroxydopamine, respectively, followed by identification of neuronal nitric oxide synthase immunoreactivity. Functional in vitro studies were also performed to examine whether the synthesis and release of nitric oxide was affected following treatment with the respective neurotoxins. Nerve fibres immunoreactive for substance P and calcitonin gene-related peptide were found in control tissue, but could not be detected following capsaicin treatment. In comparison, nitric oxide synthase-immunoreactive fibres appeared to be unaffected by capsaicin treatment. Administration of 6-hydroxydopamine resulted in a complete disappearance of tyrosine hydroxylase-immunoreactive nerves, whereas nitric oxide synthase-containing nerve fibres did not appear to be affected by the treatment. In ultrastructural studies, nitric oxide synthase immunoreactivity, as studied by colloidal gold particles, was found in the axoplasm and not in association with intraneuronal structures or synaptic vesicles. Gold particles representing substance P immunoreactivity were seen as clusters associated with large granular vesicles. In consecutive sections of nerve fibres, substance P and nitric oxide synthase were not found in the same axon profile. In functional studies on urethral tissue, application of capsaicin (1 microM) produced a long-lasting relaxation. The nitric oxide synthase inhibitor NG-nitro-L-arginine (0.1 mM) had no effect on this response. Systemic treatment with capsaicin or 6-hydroxydopamine had no effect on nerve-evoked, nitric oxide-mediated relaxations. The data suggest that nitric oxide synthase-containing nerves in the rat lower urinary tract do not belong to nerve populations sensitive to either the sympathetic neurotoxin, 6-hydroxydopamine, or the sensory neurotoxin, capsaicin.

Acetylcholinesterase↗
PubMed1997

Expression of tissue inhibitor of metalloproteinases TIMP-2 in human colorectal cancer--a predictor of tumour stage.

The aim of this study was to investigate whether immunohistochemical staining patterns of tissue inhibitor of metalloproteinases TIMP-2 and matrix metalloproteinases MMP-2 and MMP-9 can be predictors of tumour stage and survival time in colorectal cancer. Frozen tumour sections from 212 patients operated on between January 1987 and November 1990 were investigated. Three mouse monoclonal antibodies--T2-101 against TIMP-2, CA-4001 against MMP-2 and GE-213 against MMP-9--were used. Positive expression of TIMP-2 (a) in basement membranes and (b) diffusely in stroma with (c) subglandular enhancement was found significantly (P < 0.01, P < 0.05, P < 0.05) more often in localized tumours than in tumours with regional or distant metastases. Neither pattern correlated with tumour differentiation. Patterns (a) and (c) correlated with longer survival time (P < 0.05); (b) reached near significance (P < 0.07). When the survival analyses were restricted to potentially cured patients, neither pattern could foretell death from cancer. Positive expression of MMP-2 in tumour epithelium and of MMP-9 in tumour-infiltrating macrophages were both independent of tumour stage and were without correlation with survival time. A large number of MMP-9-positive macrophages correlated (P < 0.05) with poor tumour differentiation, whereas weak or absent epithelial MMP-2 staining reached near significance (P < 0.08). Exploration of TIMP-2 expression is valuable for the discrimination between macroscopically localized and metastatic colorectal cancer, but it cannot predict which of the potentially cured patients are likely to have micrometastases. MMP-2 and MMP-9 stainings are of minor value in staging and prognostic prediction.

Adult↗
PubMed1997

Heritability for Alzheimer's disease: the study of dementia in Swedish twins.

BACKGROUND: Alzheimer's disease has been thought to have familial and sporadic forms, and several genetic defects have been identified that chiefly explain early-onset familial cases. In this study, our purpose was to detect all cases of dementia in an established twin registry and to estimate total extent of genetic contribution to liability to Alzheimer's disease. METHODS: At the first stage, members of the registry were screened for dementia, using in-person or telephone mental status testing. At the second stage, those who screened positively and their partners were referred for clinical work-ups, including neuropsychological assessment, physician examination, laboratory tests, and neuroimaging. Clinical diagnoses were assigned at a multidisciplinary consensus conference. Probandwise concordance rates were examined by zygosity, and structural modeling was applied to the data to estimate genetic and environmental influences, using both single- and multiple-threshold models. RESULTS: Sixty-five pairs were identified in which one or both was demented. The probandwise concordance rate for Alzheimer's disease among monozygotic pairs was 67%; the corresponding figure for dizygotic pairs was 22%. Heritability of liability to Alzheimer's disease was estimated to be .74; to any dementia, .43. The other variance is attributable to environmental influences. CONCLUSIONS: Findings indicate a substantial genetic effect for these predominantly late-onset Alzheimer's disease cases. At the same time, structural modeling results and large intra-pair differences in age of onset suggest that environmental factors are also important in determining whether and when an individual may develop dementia.

Age of Onset↗
PubMed1997

Dementia and driving: an attempt at consensus.

The number of older drivers in Sweden will be rapidly increasing during the next decades. A possible relationship exists between the increased relative crash risk of older drivers and the prevalence of age-related diseases such as dementia. However, a clear-cut policy for evaluating driving competence in demented persons is still lacking. In recognition of this fact, the Swedish National Road Administration invited a group of researchers to formulate a consensus on the issue of driving and dementia. This consensus document is aimed at providing primary care physicians with practical advice concerning the assessment of cognitive status in relation to driving. Suggestions are based on a review of existing research and discuss the use of general and driving-specific sources of information available to the physician. Consensus was reached on the statement that a diagnosis of moderate to severe dementia precludes driving and that certain individuals with mild dementia should be considered for a specialized assessment of their driving competence.

Aged↗
PubMed1997

The 1994 International Consensus Conference on Dementia and Driving: a brief report. Swedish National Road Administration.

A possible relationship exists between the increased relative crash risk of older drivers and the prevalence of age-related diseases such as dementia. However, although dementia effects cognitive functions essential for safe driving, the evaluation of driving competence in demented persons is problematic. A clear-cut policy, intended chiefly for primary care physicians, is still lacking. In recognition of this fact, the Swedish National Road Administration invited a group of researchers to review existing research and to formulate a consensus on the issue of driving and dementia. The consensus group suggested that physicians should routinely make a cursory evaluation of the mental condition of their older driving patients. When signs of cognitive impairment are detected, possible influence on visuospatial skills, attention, judgment, and memory functions should be carefully considered. Information from caregivers on past and current driving performance as well as functions relating to activities of daily living (ADL) should be taken into account. Consensus was reached that a diagnosis of moderate to severe dementia indicates sufficient cognitive impairment to preclude driving. In addition, diagnosed mildly demented individuals or nondiagnosed cognitively impaired individuals with functional deterioration should be considered for specialized assessment of driving competence.

Automobile Driving↗
PubMed1997

In situ preservation of the parathyroid glands during operations on the Thyroid.

OBJECTIVE: To study the microcirculation of the parathyroids before and after dissection during operations on the thyroid gland to see if there were better ways of preserving them. DESIGN: Prospective open study. SETTING: University hospital, Sweden. SUBJECTS: 16 Patients undergoing operations on the thyroid gland. 20 Parathyroid glands located anteriorly on the thyroid lobe were selected for study. INTERVENTIONS: Recording of microcirculation of the parathyroids with laser Doppler flowmetry. Recording of the macroscopic appearance of the parathyroid glands. MAIN OUTCOME MEASURES: Correlation between reduction in blood flow and the macroscopic appearance of glands while they were ischaemic. RESULTS: Parathyroid microcirculation before dissection gave a mean Doppler signal level of 4.6 (1.4) V. 30 minutes after dissection to preserve the gland the remaining mean (SD) signal was 37 (24)% of the initial level. At the end of the operation the microcirculation tended to recover about 46 (21)% of the original value (p = 0.33). The macroscopic appearance of the gland during the ischaemic period did not correlate well with the reduction in blood flow. CONCLUSION: During dissection to preserve normal parathyroid glands there was a discrepancy between the macroscopic appearance and changes in the microcirculation. The microcirculation recovers and this can be verified by laser Doppler flowmetry.

Adult↗
PubMed1996

Laser Doppler blood flow measurement in rectal resection for carcinoma--comparison between the straight and colonic J pouch reconstruction.

Lower rates of anastomotic leakage have been reported after rectal resection with a colonic pouch-anal anastomosis than with a conventional straight anastomosis. The microcirculation in the bowel segment that was used for construction of a colonic pouch or a conventional straight anastomosis was examined. Transmural colonic blood flow was measured by laser Doppler flowmetry during the operation before the construction of a straight (n = 16) or pouch (n = 14) anastomosis. The blood flow recordings were first done before dissection of the bowel at one point close to the planned bowel end and at another point 8 cm more proximally. A second recording was done at the same sites after dissection and, where appropriate, after construction of the pouch, but before the anastomosis was completed. In the straight group (end-to-end anastomosis), blood flow levels at the site intended for the anastomosis were significantly decreased following dissection of the bowel. In the pouch group (side-to-end anastomosis), blood flow levels at the site of the anastomosis were similar following dissection of the bowel and pouch construction. It is concluded that unaffected blood flow at the site of the anastomosis of the pouch may be a favourable factor for anastomotic healing.

Adult↗
PubMed1996

Blood supply and parathyroid hormone secretion in pathological parathyroid glands.

The blood supply of pathologic parathyroid glands and the relation between parathyroid hormone secretion and parathyroid blood perfusion was studied during surgery for hyperparathyroidism. Blood flow in 39 single adenomas and 20 glands classified as primary or secondary hyperplasia were studied intraoperatively with laser Doppler flowmetry. The ipsilateral inferior thyroid artery was occluded during continuous flowmetry recording, which resulted in a 40% reduction of parathyroid blood flow in both groups. In 12 patients with single adenomas, intact parathormone (iPTH) was measured intraoperatively before and during occlusion of the ipsilateral inferior thyroid artery and after extirpation of the adenoma. During occlusion the iPTH levels were mainly unchanged despite blood flow reduction of up to 80%. After removal of the adenoma the iPTH normalized within 15 minutes. In a control group of eight single adenomas, iPTH was measured similarly without vascular occlusion, demonstrating comparable iPTH levels. This study demonstrates similar routes of vascularization for single adenomas and hyperplastic glands, as was earlier seen for normal parathyroid glands. The increased parathyroid hormone secretion from single adenomas appears to remain mainly unchanged during significant blood flow reduction.

Adenoma↗
PubMed1996

Selection for egg shell strength in laying hens using shell membrane characteristics.

1. Divergent selection for attachment strength between the shell membrane and the calcium shell was performed in a White Leghorn strain. Multivariate analysis was used to estimate genetic parameters for shell membrane measurements and shell thickness. The aim was to investigate the possibility of improving shell strength in laying hens by selecting for increased attachment strength. 2. A significant direct selection response for attachment strength was achieved. There was a favourable correlated selection differential in the frequency of cracked eggs which resulted in a nonsignificant but favourable, correlated response. Selection for a strong attachment resulted in a thinner egg shell, and vice versa. Heritabilities were all relatively high (0.30 to 0.70). Most of the genetic correlations were in agreement with the achieved correlated responses. 3. Two factors that probably contributed to the responses in egg shell thickness were an unfavourable genetic correlation between attachment strength and shell thickness, and natural selection against changes in attachment strength, in the form of increased mortality during incubation and hatching. Problems connected with breeding for increased shell strength are discussed.

Animals↗
PubMed1996

Vas deferens aspiration and intracytoplasmic injection of frozen-thawed spermatozoa in a case of anejaculation in a diabetic man.

By using aspiration from the vas deferens, apparently good quality spermatozoa can be obtained for in-vitro fertilization (IVF) in cases of non-treatable anejaculation. Being squeezed from the epididymis during aspiration, the spermatozoa may be immature and their fertilizing capacity lower than that of ejaculated spermatozoa. Our case report describes a couple who achieved pregnancy when intracytoplasmic sperm injection (ICSI) was carried out with frozen-thawed spermatozoa aspirated from the vas deferens of a man whose anejaculation was associated with diabetes mellitus. In the aspiration, 50 x 10(6) spermatozoa were obtained. One half of them was frozen, and the other half was used fresh for conventional IVF, resulting in total fertilization failure of all the oocytes. The second treatment was ICSI, in which eight out of 11 oocytes injected with frozen-thawed spermatozoa showed normal fertilization. The second frozen embryo transfer resulted in a normal pregnancy.

Adult↗