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Biomedical subjects

L Bolund

Publications and source records attributed to L Bolund.

12 recordsLinked to original sources
PubMed1992

Expression of wild-type and mutant medium-chain acyl-CoA dehydrogenase (MCAD) cDNA in eucaryotic cells.

An effective EBV-based expression system for eucaryotic cells has been developed and used for the study of the mitochondrial enzyme medium-chain acyl-CoA dehydrogenase (MCAD). 1325 bp of PCR-generated MCAD cDNA, containing the entire coding region, was placed between the SV40 early promoter and polyadenylation signals in the EBV-based vector. Both wild-type MCAD cDNA and cDNA containing the prevalent disease-causing mutation A to G at position 985 of the MCAD cDNA were tested. In transfected COS-7 cells, the steady state amount of mutant MCAD protein was consistently lower than the amount of wild-type human enzyme. The enzyme activity in extracts from cells harbouring the wild-type MCAD cDNA was dramatically higher than in the controls (harbouring the vector without the MCAD gene) while only a slightly higher activity was measured with the mutant MCAD. The mutant MCAD present behaves like wild-type MCAD with respect to solubility, subcellular location, mature protein size and tetrameric structure. In immunoblot comparisons, the MCAD protein was present in normal fibroblasts, but essentially undetectable in patient fibroblasts homozygous for the prevalent mutation. We suggest that the MCAD protein carrying this mutation has an impaired ability to form correct tetramers, leading to instability and subsequent degradation of the enzyme. This finding is discussed in relation to the results from expression of human MCAD in Escherichia coli, where preliminary results show that production of mutant MCAD leads to the formation of aggregates.

Acyl-CoA Dehydrogenase↗
PubMed1992

Lateral growth and terminal differentiation during repeated epidermal regeneration in vitro. Age dependence and modulation by cholera toxin.

By incubating multilayered primary cultures of human epidermal keratinocytes in a low calcium medium, the suprabasal layers can be stripped off leaving a basal cell monolayer. When this monolayer is refed normal calcium medium a reproducible series of cell kinetic, morphological and biochemical changes take place resulting in the regeneration of a multilayered tissue. The stripping procedure seems to induce the selective proliferation of a cohort of basal cells that is committed to vertical migration and rapid terminal differentiation. In contrast, when the basal cells are allowed to regenerate in the presence of the strong mitogen, cholera toxin, lateral growth and continued proliferation are favoured at the expense of the capacity of the cells to differentiate. Repeated stripping of the same cultures disclosed a considerable heterogeneity in the capacity of the basal cells to regenerate the suprabasal layers. The number of times the basal cells could restore the suprabasal layers after repeated stripping varied from four to nine times. A negative correlation between donor age and regenerative capacity was observed. The experiments with repeated stripping of the same cultures also showed that the capacity to proliferate and to restore the multilayering was fully retained for at least four cycles of stripping-regeneration, whereas the capacity to terminally differentiate was rapidly lost. It is suggested that the present system of regenerating epidermal tissue cultures may serve as an experimental model for the study of epidermal tissue homeostasis and cellular aging.

Aging↗
PubMed1992

Fast one-step procedure for the detection of nucleic acids in situ by primer-induced sequence-specific labeling with fluorescein-12-dUTP.

We provide fast, simple, one-step procedures for sequence-specific detection of nucleic acids in situ. Tandem repeat sequences in DNA are stained within 30 min, and mRNA is stained within 2 h. The procedures are based on the incorporation of the newly available fluorescein-labeled dUTP into DNA synthesized in situ by primed in situ labeling, with denatured fragments of cloned DNA or oligonucleotides as primers. The extreme speed and simplicity of the reaction make it attractive for automatization in routine laboratory procedures and opens up new diagnostic possibilities.

DNA↗
PubMed1992

Assignment of the urokinase-type plasminogen activator receptor gene (PLAUR) to chromosome 19q13.1-q13.2.

The urokinase-type plasminogen activator receptor (uPAR) is a key molecule in the regulation of cell-surface plasminogen activation and, as such, plays an important role in many normal as well as pathological processes. We applied a cDNA probe from the corresponding gene (PLAUR) in a location analysis using a panel of human/rodent cell hybrids and in a multipoint linkage analysis of 40 CEPH families. These two independent studies both found PLAUR to be located on chromosome 19. The cell hybrid study suggested that PLAUR is located at chromosome 19q13-qter, and the multipoint analysis indicated that PLAUR is located at chromosome 19q13.1-q13.2 and surrounded by DNA markers in the following way (with distances given in recombination fractions): D19S27-.11-CYP2A-.06-PLAUR-.03-D19S8-.04-APOC 2-.24-PRKCG. Further, a ligand-binding study performed on cell hybrids verified the species specificity of the uPAR and confirmed the chromosome assignment.

Animals↗
PubMed1979

Origin of triploidy in spontaneous abortuses.

Fourteen triploid spontaneous abortuses were studied cytogenetically by sequential Q and C banding and the marker chromosomes were compared with those of the parents. The abortuses comprised all triploid cases in a series of 288 consecutive abortuses of the first 16 weeks of pregnancy occurring in one hospital. In 12 of the triploids the origin of the extra haploid set was conclusively determined, revealing six cases of dispermy, five failures in the first maternal and one failure in the first paternal meiotic division. The results were combined with those of five other studies comprising a total of 48 informative cases. Non-reduction in the second meiotic division seems to be of little or no significance in the origin of human triploidy. Dispermy is the predominant source, accounting for 40--50% of the triploid spontaneous abortuses. Non-reduction in the first meiotic division of the father seems to be the second-most frequent source although in the present material the corresponding maternal non-reduction is much more common.

Abortion, Spontaneous↗
PubMed1975

Synthesis of oviduct nuclear and chromatin proteins during steroid induced differentiation.

Synthesis of nuclear histones and nonhistones was studied in chick oviduct during stimulation with estrogen and progesterone. In estrogen primed chicks, as compared to progesterone primed chicks, oviduct nonhistones are enriched in polypeptides of 50,000 daltons and larger. A secondary stimulation with the steroids increases the amino acid incorporation into histones and nonhistones two to six fold. Injection with estrogen induces preferential labelling of nonhistone polypeptides at 50,000 to 60,000 daltons independent of the kind of primary stimulation. A secondary injection with progesterone increases the amounts of highly labelled polypeptides with a molecular weight of over 70,000 daltons.

Animals↗