Search PubMed⌕ Search

Biomedical subjects

M Johansson

Publications and source records attributed to M Johansson.

At least 217 records · Page 12Linked to original sources
PubMed1994

Localization of the IGHG, PRKACB, and TNP2 genes in pigs by in situ hybridization.

The porcine genes encoding the immunoglobulin gamma heavy chain (IGHG), cAMP-dependent protein kinase catalytic beta subunit (PRKACB), and transition protein 2 (TNP2) were mapped to Chromosomes (Chrs) 7 q25-q26, 6q31-q33, and 3p13-cent, respectively, by in situ hybridization. Localization of the IGHG gene confirms the assignment of linkage group III to Chr 7. Our results show that the IGHG locus in pigs, similar to the situation in other mammalian species, viz. humans, mouse, cattle, and river buffaloes, is located on the terminal region of the chromosome. The assignment of the PRKACB gene extends the homology observed between porcine Chr 6q and human Chr 1p. Mapping of the TNP2 gene provides the first marker assigned to the p arm of Chr 3 in pigs. The present study contributes to the development of the physical gene map in pigs and also bears significance in terms of comparative gene mapping.

Animals↗
PubMed1994

A primary linkage map of the porcine genome reveals a low rate of genetic recombination.

A comprehensive genetic linkage map of the porcine genome has been developed by typing 128 genetic markers in a cross between the European Wild Boar and a domestic breed (Large White). The marker set includes 68 polymerase chain reaction-formatted microsatellites, 60 anchored reference markers informative for comparative mapping and 47 markers which have been physically assigned by in situ hybridization. Novel multipoint assignments are provided for 54 of the markers. The map covers about 1800 cM, and the average spacing between markers is 11 cM. We used the map data to estimate the genome size in pigs, thereby addressing the total recombination distance in a third mammalian species. A sex-average genome length of 1873 +/- 139 cM was obtained by comparing the recombinational and physical distances in defined regions of the genome. This is strikingly different from the length of the human genome (3800-4000 cM) and is more similar to the mouse estimate (1600 cM). The recombination rate in females was significantly higher than in males.

Animals↗
PubMed1994

Co-operation, participation and conflicts faced in public health--lessons learned from a long-term prevention programme in Sweden.

A comprehensive community-based programme for prevention of cardiovascular diseases (CVD) and diabetes was established in 1985 in a small municipality in northern Sweden. A cross-sectional survey to the general public was performed and semi-structured open-ended interviews were taken of actors at different levels. Notes from official records were also included in the study. The aim was to describe and discuss some factors that promote or constrain community participation in health programmes. The results generally confirmed that the right of definition concerning the health programme mainly remained with the health professionals. Community participation was mainly defined by the actors based on the medical and health planning approach and, thereby, as a means to transform health policy plans into reality by transmitting health knowledge and increasing consciousness among the citizens of the need for changing lifestyles. However, participation as a means of identifying problems and demonstrating power relationships and as elements in promoting local democracy was hardly represented among the actors at all. Overall, the CVD health programme was characterized by consensus between the actors. Despite this, debates and arguments about interpretations, social interests, personal conflicts and ideological constraints were observed. However, a majority of the public wanted the CVD preventive programme to continue.

Adult↗
PubMed1994

Integrating the porcine physical and linkage map using cosmid-derived markers.

An essential part in the development of informative linkage maps is to include genetic markers that have been anchored by physical mapping. Here a set of 18 porcine cosmid-derived genetic markers are reported that have been mapped by linkage analysis, and that also have been physically localized by fluorescence in situ hybridization (FISH). Three different strategies were used to establish polymorphic markers from the cosmid clones. Firstly, dinucleotide microsatellite loci were derived by sequencing cosmid subclones containing (CA)n repeats. Secondly, variable SINE 3' poly(A) tracts (SINEVA) were identified by direct SINE-PCR amplification of cosmid clones. Thirdly, the cosmids were used in Southern blot hybridization to detect restriction fragment length polymorphisms (RFLPs). Compared with the most recent consensus compilation of the porcine gene map, the present assignment of markers to chromosomes 2p, 3, 4, 10, 12q, and 16 represents the first loci mapped to these chromosomes, for which linkage as well as in situ data are now available.

Animals↗
PubMed1994

Abnormal DNA synthesis in polyamine deficient cells revealed by bromodeoxyuridine-flow cytometry technique.

Chinese hamster ovary cells were seeded in the absence or presence of the polyamine synthesis inhibitor 2-difluoromethylornithine (DFMO). At 1-4 days after seeding, the cells were labelled for 15-120 min with the thymidine analogue bromodeoxyuridine (BrdUrd) and they were then fixed directly after the labelling period. In addition, cells were labelled for 30 min and they were then allowed to progress in BrdUrd-free medium during a defined post-labelling time before fixation. An indirect immunofluorescence technique, using the monoclonal BrdUrd antibody and the intercalating stoichiometric DNA stain, propidium iodide, was applied to enable quantification of cellular BrdUrd and DNA contents, respectively, by flow cytometry (FCM). By comparing the mean DNA content of BrdUrd-labelled cells to the mean DNA contents of G1 and G2 cells, a relative measure of the position of the BrdUrd-labelled cells was obtained (relative movement). Relative movement data, obtained from control and DFMO-treated cells fixed directly after BrdUrd labelling, indicated that DFMO-treated cells entered S phase at a normal rate, while their progression through S phase was impaired. DNA histograms of BrdUrd-labelled control cells fixed directly after labelling showed that most cells were found in early and late S phase, while DNA histograms of BrdUrd-labelled DFMO-treated cells showed that most cells were in early S phase, indicating a delayed progression through S phase. Analysis of relative movement of cells that were allowed to progress in BrdUrd-free medium after labelling showed that DFMO treatment resulted in a significant lengthening of the DNA synthesis time. Labelling index was significantly higher in DFMO-treated, growth-inhibited cells than in early plateau phase control cells indicating an S phase accumulation in the former cells.

Animals↗
PubMed1994

Target and neurotransmitter specificity of fetal central nervous system transplants: importance for functional reinnervation.

The ability of grafted fetal ventral mesencephalic dopaminergic (DAergic) neuroblasts to reinnervate the unilaterally DA denervated rat striatum and improve motoric asymmetry has been well documented in several laboratories. The importance of host target specificity, and catecholamine (CA) neurotransmitter species, in the ability of grafts to ameliorate rotational responses to apomorphine and to affect electrophysiological characteristics of striatal neurons has not been systematically studied. We unilaterally lesioned Sprague-Dawley rats with 6-hydroxydopamine (6-OHDA) and verified the lesions using apomorphine (0.05 mg/kg, s.c.)-induced rotational behavior. Some of the animals subsequently received, intrastriatally, either DA neuroblasts from ventral mesencephalon that normally innervate the striatum, or from arcuate nucleus that do not. Additionally, two other groups were included that received either a CAergic graft from the noradrenergic nucleus locus coeruleus or a graft of cerebral cortex, which normally projects to the striatum but does not contain CAergic neurons. Only the fetal ventral mesencephalic grafts were able to reduce apomorphine-induced rotations and normalize striatal cell firing rates; striatal cell firing rates with ventral mesencephalic grafts were 1.43 Hz +/- 0.22, with arcuate nucleus grafts were 6.03 +/- 0.73, with locus coeruleus grafts were 4.71 +/- 0.74, and with cerebral cortex grafts were 4.36 +/- 0.45. Moreover, only the ventral mesencephalic grafts produced a dense tyrosine hydroxylase (TH)-immunoreactive nerve terminal network in the striatum; in contrast, the arcuate nucleus grafts did not reinnervate the striatum. In locus coeruleus grafted striata, few very long TH-positive axons were seen. We thus conclude that target specificity and neurotransmitter type are critically important in the ability of a graft to functionally reinnervate the 6-OHDA denervated striatum.

Animals↗
PubMed1994

The need for requirements engineering in the development of clinical decision-support systems: a qualitative study.

Insufficient requirements analysis has recently been suggested as a problem in clinical decision-support systems development. Therefore, to explore knowledge, practices and attitudes, key professionals in the area from four countries were interviewed regarding the early phases in the development process. For data collection, semi-structured interviews were performed and video-taped. As reference, documentation of the Action Design requirements engineering methodology was used. Two separate qualitative analyses of the data were made. The first was to identify central concepts and attitudes related to requirements engineering. In the second analysis, concrete circumstances surrounding decisions to use requirements engineering methods were investigated. This paper reports the results of the analyses and discusses changes in the planning and management of clinical decision-support projects in general, and it comments on development methods, using Action Design as reference. It is concluded that studies are needed to further investigate the problems real decision-support projects have to deal with. This knowledge can then be used to develop methods and tools which support design practices where existing structural, procedural and, building on this, technical obstacles are overcome.

Decision Support Techniques↗
PubMed1993

[Healthy children].

Explore the source record for details and available documents.

Abortion, Spontaneous↗
PubMed1993

Major histocompatibility complex monomorphism and low levels of DNA fingerprinting variability in a reintroduced and rapidly expanding population of beavers.

Loss of genetic variation due to population bottlenecks may be a severe threat for the survival of endangered species. Assessment and maintenance of genetic variability are thus crucial for conservation programs related to endangered populations. Scandinavian beavers went through an extensive bottleneck during the last century due to overhunting. In Sweden the species became extirpated but in Norway extinction was avoided by legal protection. Following reintroductions of small numbers of remaining Norwegian animals in 1922-1939, the Swedish population has increased tremendously, now harboring 100,000 animals. We show here that this viable population of beavers possesses extremely low levels of genetic variability at DNA fingerprinting loci and monomorphism at major histocompatibility complex (MHC) class I and class II loci. A similar pattern was also evident among Norwegian beavers but low levels of genetic variability were not a characteristic of the species since Russian conspecifics displayed substantial DNA fingerprinting polymorphism. However, the Russian animals were monomorphic at MHC loci, indicating that the European beaver is exceptional in its low level of MHC variability. The results demonstrate that a conservation program can be successful despite low levels of genetic variation in the founder population.

Animals↗
PubMed1993

Glial cell line-derived neurotrophic factor is expressed in the developing but not adult striatum and stimulates developing dopamine neurons in vivo.

The potential role of glial cell line-derived neurotrophic factor (GDNF) as a trophic molecule for midbrain dopamine neurons was examined using two different approaches: in situ hybridization and intraocular transplantation. The presence of mRNA for GDNF was noted in striatal and ventral limbic dopaminergic target areas in the developing (E20-P7) rat, but not the adult rat. Signals were also found in nondopaminergic areas during maturation, such as the cerebellar anlage, spinal cord, and thalamus. Lesions of the nigrostriatal pathway in neonatal or adult rats, using 6-hydroxydopamine injected into the medial forebrain bundle, did not elicit upregulation of mRNA for GDNF. Grafts of fetal ventral mesencephalon in the anterior eye chamber were exposed to repeated injections of GDNF, which elicited a marked and dose-dependent increase in transplant volume. A low (0.1 microgram/eye) and high (1 microgram/eye) dose of GDNF both led to a somewhat larger mean area of dopamine fiber outgrowth into host irides. In the transplants, cell counts of tyrosine hydroxylase (TH)-immunoreactive neurons revealed a doubling of cell numbers in the low-dose group and about four times as many cells in the high-GDNF-dose group compared to controls. Moreover, the density of TH-immunoreactive nerve fibers was markedly and significantly higher in transplants treated with the high GDNF dose. Since the volumes of these transplants were also larger, the total amount of both TH-positive cells and TH-positive nerve fibers was many-fold greater in the high-GDNF group than that in the controls. Taken together, these data support the concept that GDNF functions as a dopaminotrophic factor in vivo.

Aging↗
PubMed1993

Assignment of 20 microsatellite markers to the porcine linkage map.

Twenty-one porcine microsatellite markers were developed by screening DNA libraries and by a computer search of databases. The microsatellites were typed in a large three-generation family established by a cross between the European wild pig and a Swedish Yorkshire breed. Linkage analysis benefited from the fact that due to the divergence between the parental populations, the degree of microsatellite polymorphism was significantly higher in the F1 animals than in either of the parental populations. Parallel typing of a set of 35 restriction fragment length polymorphism, protein, and blood group markers rendered it possible to assign as many as 20 of the microsatellites to the porcine linkage map. Fourteen microsatellites were localized to a chromosome segment, whereas six constituted parts of unassigned linkage groups. Analysis of four microsatellites within genes allowed the assignment of the endoplasmic reticulum Ca2+ transport ATPase locus to chromosome 14, the assignment of the interferon-gamma and the diacylglycerol kinase loci to a new linkage group (XI), and the localization of the tumor necrosis factor beta locus close to the major histocompatibility complex (SLA) on chromosome 7 to be confirmed. Fluorescence in situ hybridization mapping of two microsatellite-containing cosmids assigned two linkage groups to chromosomes 9 and 12, respectively. In total, 27 new markers were added to the porcine linkage map, thereby almost doubling the number of markers on the map. Linkage groups are now present on 10 of 18 of the pig autosomes.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Positively charged amino acids placed next to a signal sequence block protein translocation more efficiently in Escherichia coli than in mammalian microsomes.

Positively charged amino acids are known efficiently to block protein secretion in Escherichia coli, when placed within a short distance downstream of a signal sequence. It is not known whether the same applies to protein secretion in eukaryotic cells, though statistical studies of signal sequences of prokaryotic and eukaryotic secretory proteins have suggested that the situation may be different in this case. Here, we show that identical charge mutations in a model protein have different effects on membrane translocation in E. coli and in mammalian microsomes, and that the 'charge block' effect is much more pronounced in the prokaryotic system. This finding has implications not only for our understanding of the mechanisms of protein secretion, but also points to a potential problem in the expression of eukaryotic secretory proteins in bacteria.

Amino Acid Sequence↗
PubMed1993

Assignment of the linkage group EAM-TYRP2-TPP2 to chromosome 11 in pigs by in situ hybridization mapping of the TPP2 gene.

Restriction fragment length polymorphisms are described for the genes coding for tripeptidyl peptidase II (TPP2) and tyrosinase related protein II (TYRP2) in pigs. A linkage group comprising these loci and the locus for blood group M (EAM) was established by two-point lod score analysis in a three-generation pedigree. Multipoint analysis indicated the linear order EAM-1.1-TYRP2-8.4-TPP2 (recombination distances are given as Kosambi cM). The linkage group was assigned to porcine chromosome 11--the first on this chromosome--through in situ hybridization mapping of the TPP2 gene. TPP2 is the first gene localized on this chromosome using in situ hybridization.

Aminopeptidases↗
PubMed1993

Cytogenetic analysis of six bronchial carcinoids.

Short-term cultures from four typical and two atypical primary bronchial carcinoids were cytogenetically analyzed. A lung metastasis from one of the atypical carcinoids was also analyzed. Of the four typical carcinoids, two had normal chromosome complements, while the other two had the karyotypes 46,X, -X, +7/47,XX, +7/47,XX, +X/46,XX and 47,XX, +7/46,XX. Both atypical carcinoids had chromosome abnormalities. One had the karyotype 45-46,X, -X,del(1)(q32),add(17)(p13), +add(19)(p13), -22, +r/47,XX, +X. The second carcinoid had the karyotype 78-81,XXY, +Y, +1,t(2;8)(q21;q24), +3, +4, +del(4) (q25), +5, +6,der(6)t(6;6)(q21;p21)x2, +7, +7, -10,add(14)(p11-13), +19, -21, +1-4mar. The metastasis from this carcinoid had the same aberrations, except that the del(4)(q25) had been lost and one to two markers had been gained.

Bronchial Neoplasms↗