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Biomedical subjects

K Johansson

Publications and source records attributed to K Johansson.

At least 91 records · Page 5Linked to original sources
PubMed1996

Pregnancy resulting from intracytoplasmic injection of spermatozoa from a frozen-thawed testicular biopsy specimen.

A testicular biopsy specimen was taken in connection with scrotal exploration of a healthy 35 year old man who had azoospermia. Bilateral severe scarring of unknown aetiology was found in the exploration, and no epididymal spermatozoa could be obtained. Spermatozoa from the fresh biopsy specimen were used for intracytoplasmic sperm injection (ICSI) on the same day. Two-embryo transfer resulted in biochemical pregnancy. The rest of the biopsy specimen was frozen as small pieces of tissue using glycerol as a cryoprotectant. ICSI was then performed with spermatozoa prepared from the frozen-thawed tissue. One embryo was obtained and transferred. The transfer resulted in pregnancy, and a living fetus was seen in ultrasound scans at the seventh and 16th weeks of pregnancy. It is possible to avoid repeated testicular biopsies by using cryopreservation of testicular tissue.

Adult↗
PubMed1996

Speech gestures and facial expression in speechreading.

Two experiments investigated the role of facial expression in speechreading. In Experiment 1 sentences were presented either with only the actor's face shown or with the actor shown in half-size. One happy script with happy, sad and neutral sentences was used, and either a content cue or an emotional cue was presented prior to each sentence. In Experiment 2 happy and sad sentences from one happy and one sad script were first recorded by the actor with a neutral face (face and shoulder shown) and then with a congruent facial expression. The results revealed that there was no difference in performance between half-size and face presentation, but content cues increased performance compared to emotional cues. As expected (Abelson, 1981), happy sentences were easier to speechread than sad in the happy script and vice versa. Also, facial expression raised performance for happy sentences in the happy script. Positive emotions are suggested to be associated with approach behavior in part relying on increased non-pantomimic speech gestures and articulation of the speaker (e.g., Davidson et al., 1990).

Adult↗
PubMed1996

Can a physician recognize an older driver with increased crash risk potential?

OBJECTIVE: To identify factors in a medical examination that distinguish convicted older drivers with traffic violations from other drivers. DESIGN: Matched case-control study. SETTING: Two countries in Sweden. SUBJECTS: Thirty-seven drivers older than age 65, whose driving licenses have been temporarily suspended, each matched to one control subject based on age, sex, type of driving license, year of first license, living area, educational level, and annual distance driven. MEASUREMENTS: Case and control subjects were compared with respect to medical history, medication use, blood tests, drawing and memory tests, Mini-Mental State Examination, medical status findings, visual acuity, and brain imaging procedures. MAIN RESULTS: The group of drivers with suspended driving licenses did not differ from matched controls with respect to visual acuity or presence of cardiovascular diseases. However, persons with suspended driving licenses were more likely than control subjects to have suspected or mild dementia (P < .010) and to perform less well on two easily administrated screening tests: copying a cube (P < .010) and 5-item recall (P < .010). Case subjects with crashes had significantly more cardiovascular diseases than case subjects with other moving violations (P < .050). These case subjects with crashes also had significantly more cognitive impairments than control subjects without crashes as shown by a higher clinical dementia rating score (CDR) (P < .001), lower score on the Mini-Mental State Examination (MMSE) (P < .050), and lower level of performance in the copying task (cube) (P < .050) and 5-item recall test (P < .010). They also had evidence of greater cognitive impairment than those case subjects with other moving violations. CONCLUSIONS: Visual acuity and common medical examination did not distinguish convicted older drivers with crashes or other moving violations from controls. There was evidence that even mild cognitive impairment contributed to the risk of losing a driving license because of crashes.

Accidents, Traffic↗
PubMed1996

Medical screening of older drivers as a traffic safety measure--a comparative Finnish-Swedish evaluation study.

OBJECTIVES: To evaluate the safety effect of age-related medical screening of older drivers by comparing the licensing laws and accident rates for older road users in Finland and Sweden. DESIGN: Post hoc comparison of Sweden and Finland with respect to three different risk variables. SETTING: Nationwide Swedish and Finnish accident, licensing, and population data from the year 1990 were provided for the present study by the local authorities responsible for tabulating these data. PARTICIPANTS: Data about all citizens born in 1960 or earlier, i.e., aged 30 years or more in the year of measurement, are included. MEASUREMENTS: Rates of police-reported private car accidents leading to personal injury, fatality rates of private car drivers and passengers, and fatality rates of unprotected road users. RESULTS: The age-related variation in private car accident and private car fatality trends was similar in both countries. Fatalities among unprotected road users (i.e., pedestrians, cyclists, and mopedists) increased more sharply with age among the older Finnish population than among the Swedish population. CONCLUSION: We found no safety-related reasons to implement age-related medical screening of older drivers of the kind practiced in Finland. On the contrary, by producing a modal shift toward a more risky mode of travelling, this screening may indirectly lead to higher fatality rates among older road users.

Accidents, Traffic↗
PubMed1996

Charges extracted from dental ceramics: an indication of piezoelectric activity?

A method was established for demonstrating charge generation on the surfaces of dental materials by means of mechanical loading with different forces. With this experimental set-up charges could be extracted both from the surfaces that were mechanically loaded and from the surfaces perpendicular to the applied force. When specimens of certain ceramics were subjected to mechanical loading and the charges extracted were related to the applied force, charges of up to 3 x 10(-3) pC/N were recorded from the surfaces perpendicular to the applied force and charges of up to 8 x 10(-3) pC/N from the surfaces that were mechanically loaded. The results from this study indicate support for the hypothesis that the extracted charges were created by direct piezoelectricity. However, further studies are necessary for decisive proof that true piezoelectricity occurs in these materials.

Ceramics↗
PubMed1996

Facial expressions and speechreading performance.

In the present study, the role of facial expressions in visual speechreading (lipreading) was examined. Speechreading was assessed by three different tests: sentence-based speechreading, word-decoding, and word discrimination. Twenty-seven individuals participated as subjects in the study. The results revealed that no general improvement as a function of expression was obtained across all tests. Nevertheless, skilled speechreaders could significantly improve their performance as a function of emotional expression in the word-decoding and word-discrimination conditions. Furthermore, a correlational analysis indicated that there was a significant relationship between the subjects' rating of confidence regarding their responses to each test-item and performance on speechreading tests where lexical analysis is a necessary task-demand. The results are discussed with respect to how information from facial expressions is integrated with the information given by the lip movements in visual speechreading, and also with respect to general models of face-processing (i.e., Bruce & Young, 1986; Young & Bruce, 1991).

Adult↗
PubMed1996

NADPH-diaphorase expression of endothelial cells during four weeks' healing of a stretch-ePTFE graft: an experimental porcine study.

Endothelial Nitric Oxide Synthase (eNOS) mediates the conversion of L-argine to NO and citrulline, which requires Nicotinamide Adenine Dinucleotide Phosphate (NADPH) as an essential cofactor. Evidence has been given that NOS accounts for the NADPH-diaphorase activity. The aim of the present study was to identify the histochemical and immunocytochemical appearance of NADPH-diaphorase and von Willebrand factor (factor VIII) respectively, in endothelial cells (ECs) during healing of stretch-expanded polytetrafluoroethylene (ePTFE) arterial grafts. On six Swedish domestic pigs an iliac bypass was bilaterally performed using 6 mm stretch-ePTFE grafts. The animals were allowed to survive one, two or four weeks. After explanation the grafts were prepared for NADPH-diaphorase histochemistry and factor VIII immunohistochemistry. Positive staining for the two identification markers was demonstrated after two weeks, whereas a more intense staining was seen after four weeks at the proximal and distal anastomoses, indicating maturation by time. No stained cells were observed at the mid-region of the grafts at any time. The cells differed from normal ECs, the former being less intense which may reflect immature ECs and probably a decreased expression of NO. In conclusion, the present study suggests tha NADPH-d histochemistry can be used to identify ECs. Whether a lower expression of NO compared to normal cells also means a reduced function, capable of causing adverse events has to be further evaluated.

Animals↗
PubMed1995

A gene for autosomal dominant progressive cone dystrophy (CORD5) maps to chromosome 17p12-p13.

Inherited retinal dystrophy is a common cause of visual impairment. Cone dystrophy affects the cone function and is manifested as progressive loss of the central vision, defective color vision, and photophobia. Linkage was demonstrated between progressive cone dystrophy (CORD5) and genetic markers on chromosome 17p12-p13 in a five-generation family. Multipoint analysis gave a maximum lod score of 7.72 at the marker D17S938. Recombinant haplotypes in the family suggest that the cone dystrophy locus is located in a 25-cM interval between the markers D17S926/D17S849 and D17S804/D17S945. Furthermore, one recombination was detected between the disease locus and a microsatellite marker in the candidate gene RCV1, encoding the retinal protein recoverin. Two additional candidate genes encoding retinal guanylate cyclase (GUC2D) and pigment epithelium-derived factor (PEDF) are located at 17p13.1. Moreover, loci for retinitis pigmentosa and Leber congenital amaurosis have been mapped to the same region. Identification of the cone dystrophy locus may be of importance not only for identifying functional genes in the cone system, but also for identifying genes for other retinal disorders.

Chromosome Mapping↗
PubMed1995

Co-existence of nitrergic, peptidergic and acetylcholine esterase-positive nerves in the pig lower urinary tract.

The distribution of NO synthase (NOS) immunoreactive nerves and the possible co-existence with other neurotransmitters were investigated in the pig lower urinary tract. NOS immunoreactive nerves were found in the muscle layer, in the lamina propria and around blood vessels. The density of NOS immunoreactive nerves was more prominent in the trigone and urethra than in the detrusor. All parts of the lower urinary tract were supplied by numerous acetylcholine esterase (AChE) positive nerves. The number of adrenergic nerves in the trigone and urethra was moderate to rich, whereas only very few adrenergic nerves were demonstrated in the detrusor. A low to moderate number of nerve fibres containing neuropeptide Y (NPY) and vasoactive intestinal polypeptide (VIP) were observed in the trigone and urethra, while very few were found in the detrusor. A small number of nerves, confined to the trigone and urethra, were stained for calcitonin-gene-related peptide, somatostatin and leu-enkephalin. Nerve fibres exhibiting immunoreactivity to bombesin/gastrin releasing peptide, gastrin/cholecystokinin, substance P or neurokinin A were virtually absent. Co-localization studies revealed that some NOS-immunoreactive nerves also stained for NPY, VIP or AChE. The present study shows that nitrergic nerves are present in the pig lower urinary tract in a density lower than the cholinergic, but higher than any of the studied peptidergic nerves. Coinciding localization of NOS-positive nerves with nerves expressing AChE, VIP and NPY suggests that NO may have a role as a messenger in the lower urinary tract directly and by interaction with other transmitters.

Acetylcholinesterase↗
PubMed1995

Bacterial translocation and intestinal capillary permeability following major liver resection in the rat.

Bacterial infections constitute a major cause of morbidity and mortality after major liver resection and mechanisms of this type of complication have been poorly understood. The present study evaluated the translocation of enteric bacteria to mesenteric lymph nodes, viscera, and the systemic circulation and gut capillary permeability of a fine ultrastructural tracer in rats subjected to sham hepatectomy or 70% hepatectomy. Furthermore, the preventive effects of water-soluble ethylhydroxyethyl cellulose (EHEC) were studied. Cultures of all samples from rats subjected to sham hepatectomy or 70% hepatectomy with preoperative intravenous administration of EHEC were bacteriologically negative. The incidence of bacterial translocation from the gut to the systemic circulation and mesenteric lymph nodes was 30 and 80%, respectively (P < 0.01), and to the liver and kidneys 50 and 40%, respectively (P < 0.05), 12 hr after 70% hepatectomy. Intestinal capillary permeability and endothelial cell membrane permeability increased with the development of bacterial translocation. Translocating bacteria appeared within the cytoplasm of capillary endothelial cells. EHEC restored the changes in gut capillary permeability induced by major liver resection. These results indicate that gut capillary permeability may play an important role in maintaining the integrity of the gut barrier function and that increased permeability may be associated with the development of gut barrier failure.

Animals↗
PubMed1995

Driver licenses as a measure of older drivers' exposure: a methodological note.

The limitations of the number of driver licenses as an estimate of driving exposure were demonstrated by comparing Finnish and Swedish driver licensing practices, licensing rates and accident rates of older drivers. In Sweden, there is no screening for older license holders, and most of them keep their licenses for life. In Finland, there is a heavy and costly medico-legal control system for older license holders, leading to both screening and self-screening. Consequently, in the two countries, the numbers of driver licenses do not reflect the numbers of active older drivers in the same manner. This difference affects the comparative accident statistics: with respect to population, Finland and Sweden have similar age trends in accidents risk, but with respect to the number of driver licenses, the Finnish older drivers seem to have a higher risk of accident than the Swedish ones. It is concluded that if group comparisons of accident risk are presented using the number of driver licenses as an estimate of exposure, the licensing legislation and practice should affect all the groups in an identical manner for the comparison to be valid.

Accidents, Traffic↗
PubMed1995

Real-time analysis of Oct protein-octamer interaction and transcription complex assembly.

Specific interactions between the protein-binding sequence of the immunoglobulin transcription regulatory element, the octamer, and Oct proteins have been investigated using a biosensor based on surface plasmon resonance. By analysis of in vitro translated Oct1 and Oct2A with a consensus octamer probe, it was shown that the affinity constant, association rate constant and dissociation rate constant of Oct1 were higher than for Oct2A. The biggest difference was in the association rate constants, but this difference was reduced when an octamer motif containing a point mutation was used as a probe. Elements in the octamer flanking sequence could increase the on-rate of Oct proteins to a mutated octamer while not decreasing the off-rate. Oct-octamer interaction in whole nuclear extracts could be detected readily in the biosensor and adapter interactions with template bound proteins were revealed. Thus, biosensor analysis represent a fast and convenient alternative approach to study specific protein-DNA and protein-protein interactions in analysis of transcriptional regulation.

B-Lymphocytes↗
PubMed1995

The role of emotionality and typicality in speechreading.

Two experiments were carried out to investigate how emotionality and typicality could influence speechreading performance. Typical and atypical sentences for a certain script, and emotional sentences (happy and sad content, presented with happy, sad or neutral facial expression) were shown without sound on a TV-screen. Two different scripts (restaurant and doctor) were used. In Experiment 1, hearing-impaired subjects participated and in Experiment 2, normal-hearing subjects participated. Experiment 2 also evaluated the effects of tactile information. The results from both experiments showed that typical restaurant sentences were the easiest to speechread of all sentence-types, in line with script-theory (Abelson, 1981; Anderson, 1983; Bellezza & Bower, 1981; Nottenburg & Shoben, 1980; Yekovich & Walker, 1986). For the doctor script, sad sentences were better speechread than happy sentences, also according to script-theory. In addition, perception of emotional content was enhanced by tactile information. Generally, both the cognitive and emotional effects are script-dependent, suggesting important social constraints on speechreading accuracy.

Adult↗
PubMed1995

Apolipoprotein epsilon 4 allele in Swedish twins and siblings with Alzheimer disease.

Allelic frequencies of apolipoprotein epsilon 4 were compared in 13 dizygotic twin pairs and 13 sibling pairs in which at least one member has Alzheimer disease (AD). Among discordant pairs of twins and siblings, frequencies were significantly greater in affected than intact partners. There was no significant difference in allelic frequencies between twins with a positive family history and twins with a negative family history. The epsilon 4 allele was more common in the sibling sample selected for family aggregation of AD than the twin sample. Several lines of evidence indicate that while the epsilon 4 allele appears to be one risk factor for AD, other etiological factors must be considered as well.

Aged↗
PubMed1994

Central plasticity in rat trigeminal primary sensory neurons innervating vibrissae after neonatal peripheral nerve injury.

This study was undertaken to investigate whether a neonatal vibrissa lesion in the rat may lead to a central plasticity in undamaged vibrissae innervating primary sensory neurons. One vibrissa follicle was removed on the day of birth. After 3-4 months, choleragenoid-horseradish-peroxidase was injected in an adjacent vibrissa follicle either within the row of the missing follicle or across the rows and in the corresponding contralateral follicle. The trigeminal ganglion and nucleus caudalis was studied following retrograde and transganglionic transport of the tracer. The number of labeled cells was not significantly different on the two sides, whereas the central terminal field of labeling was considerably increased on the side of the lesion, but only when the injected follicle was located in the same row as the missing one. Cortical plasticity after neonatal vibrissae follicle lesions may thus be associated with a corresponding plasticity in primary sensory neurons innervating the vibrissae.

Animals↗
PubMed1994

Enzyme-based biosensor as a selective detection unit in column liquid chromatography.

A reagentless enzyme electrode based on co-immobilized alcohol oxidase and horseradish peroxidase was used as the working electrode in an amperometric flow-through cell connected to a column liquid chromatographic (CLC) system for the selective detection of methanol and ethanol. The enzymes were covalently immobilized in carbon paste (graphite-phenylmethylsilicone oil) in the presence of polyethylenimine. Electrodes prepared from the enzyme-modified carbon paste were optimized with respect to their sensitivity and selectivity. Different membranes were cast or electropolymerized directly on the surface of the electrode to increase the long-term stability of the biosensor. The compatibility with the reversed-phase chromatographic system was established. A PLRP-S polymer-based separation column was used with phosphate buffer as the mobile phase. The selectivity of the enzyme electrode was also determined by injecting some easily oxidizable and possibly interfering species normally present in biological samples. The enzyme electrode was also used in an on-line system, consisting of a microdialysis probe as the sampling unit, the CLC system and the biosensor detection device, for the selective following of the ethanol produced when a paper pulp industrial waste water was fermented with Saccharomyces cerevisiae.

Biosensing Techniques↗