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L Pulkkinen

Publications and source records attributed to L Pulkkinen.

125 records · Page 7Linked to original sources
PubMed1992

Expression of decorin in human tissues and cell lines and defined chromosomal assignment of the gene locus (DCN).

Earlier studies had shown that the expression of the gene coding for one eminent connective tissue proteoglycan, decorin (DCN), is deficient in the fibroblasts of 3 out of 15 Marfan patients (Pulkkinen et al., 1990). To obtain more information on the expression of this gene, various human tissues and cell lines were studied. High mRNA levels of decorin were detected in aorta, lung, skin, kidney, smooth muscle, and placenta, whereas significantly lower mRNA levels were found in the rest of the tissues analyzed. Two sizes of transcripts were observed in all tissues. The two transcripts of decorin most probably do not represent two different genes, since in situ hybridization gave only one strong signal, placing the gene in 12q21----q22. No tissue-specific differences in the two mRNA species of decorin were detected. This is in contrast to the gene of versican, another connective tissue proteoglycan gene, that was analyzed as a control; high expression of a longer transcript of the versican gene was found in brain and smooth muscle, whereas the shorter transcript was predominant in all other tissues studied. DCN was actively transcribed in cultured mesenchymal cells, whereas in cells of endothelial or epithelial origin, the transcription level was undetectable. These tissue- and cell type-specific variations in the expression of DCN may help to explain the complex phenotypic variation typical of individuals with Marfan syndrome.

Adult↗
PubMed1990

Deficient expression of the gene coding for decorin in a lethal form of Marfan syndrome.

The markedly decreased level of the messenger RNA of decorin, an abundant dermatan/chondroitin sulfate proteoglycan was found in the skin fibroblast culture of a lethally sick Marfan infant. Also, the amount of decorin polypeptide in the culture medium of the fibroblasts of this infant was markedly decreased. When the effect of interleukin-1 beta on the transcription of decorin was tested in these fibroblasts, the response was deficient as compared to control fibroblasts whereas transcription of type I and III collagen genes and versican was stimulated normally. The decreased decorin mRNA level, unresponsive to interleukin-1 beta in this lethally sick Marfan patient, stresses the significance of this proteoglycan in the formation of normal connective tissue. Furthermore, the low expression of this gene could be responsible for the connective tissue findings in this patient, representing a rare type of Marfan syndrome. The identical finding in three other, unrelated Marfan individuals suggests a more general significance of deficient decorin expression in this disease.

Blotting, Western↗
PubMed1990

Location on chromosome 15 of the gene defect causing Marfan syndrome.

BACKGROUND: Marfan syndrome, "the founding member" of the heritable disorders of connective tissue, is a common autosomal dominant disorder with highly variable clinical manifestations in the skeletal, ocular, and cardiovascular systems. The fundamental defect leading to this disease has escaped definition despite decades of research efforts by several groups of investigators. METHODS AND RESULTS: Using linkage analyses with polymorphic markers of the human genome, we mapped the genetic defect to chromosome 15 in five families with Marfan syndrome. With three polymorphic markers we obtained definitive proof of linkage in these families (lod score = 3.92, theta = 0.0 +/- 0.11). The most probable location of the gene for the disease is currently D15S45 (lod score = 3.32, theta = 0.0 +/- 0.12). CONCLUSIONS: The chromosomal localization of the mutation in Marfan syndrome is a first step toward the isolation and characterization of the defective gene and serves as a diagnostic test in families in which cosegregation of these markers with the disease has been confirmed.

Chromosome Mapping↗
PubMed1986

Restriction map of virulence plasmid in Yersinia enterocolitica O:3.

Restriction map of the 72-kb virulence plasmid isolated from Yersinia enterocolitica O:3 was generated using EcoRI, BamHI, HindIII, and XbaI restriction enzymes. The mapping was done after cloning all of the 13 BamHI fragments of the plasmid in Escherichia coli. In addition, the restriction enzyme analysis revealed two types of virulence plasmids (types I and II) in Y. enterocolitica O:3. No functional differences between the strains bearing type I or type II plasmid were observed.

Arthritis, Infectious↗
PubMed1986

Emergence of trimethoprim resistance in relation to drug consumption in a Finnish hospital from 1971 through 1984.

Emergence of trimethoprim resistance among urinary tract Escherichia coli strains, isolated mostly from long-term patients in the Turku City Hospital, Turku, Finland, was studied from 1971 through 1984. Emergence of resistance to trimethoprim was associated with changes in the consumption of both trimethoprim-sulfamethoxazole and trimethoprim, with occurrence of high-level trimethoprim resistance and sequences homologous to trimethoprim resistance transposon Tn7. Since 1971, resistance of E. coli to trimethoprim-sulfamethoxazole increased from 8 to between 32 and 35% in 1983 and 1984; resistance to sulfamethoxazole varied from 39 to between 40 and 44%. The frequency of DNA sequence homology with our Tn7 probe among trimethoprim-resistant E. coli strains was 42% from 1980 to 1981 and 64% in 1983 (P less than 0.005). Fourteen years after the introduction of trimethoprim therapy in this hospital, resistance has reached the level of resistance to sulfonamide.

Drug Combinations↗
PubMed1986

How to find a mutation behind an inherited disease.

The search for the mutations causing human diseases is reaching new gene areas with increasing speed with new cloned genes or polymorphic gene areas, being reported every week. The almost 300 cloned genes and over 1000 RFLP-loci of the human genome can be used as tools to approach most human gene defects. Once the linkage between the disease and the RFLP has been found, chromosomal "jumping" or pulsed field electrophoresis can be used to separate the DNA areas in the neighbourhood of the first found RFLP locus for more detailed studies and finally for the location of the defective gene. Once found, the detailed analysis of gene mutations still requires the use of several, technically very demanding approaches of molecular biology. New techniques, such as the multiplication of the required gene area in a test tube as well as RNase protection assays have been used successfully to pick out about 80-90% of the mutations which occur in one gene area and cause the disease of this gene area. The increased specificity and sensitivity of these modern approaches do not, however, necessarily lead to the rapid diagnosis of all inherited diseases. Even once a linkage has been established between RFLP locus and a disease the path is still a long one: as demonstrated in Duchenne's muscular dystrophy and Huntington's disease, we have diagnostic RFLP-linkages but the search for the gene defect continues. Further, the increased sensitivity of the mutation assays will eventually reveal all the variations in an individual.(ABSTRACT TRUNCATED AT 250 WORDS)

DNA Restriction Enzymes↗
PubMed1985

Trimethoprim resistance of Escherichia coli in outpatients in Finland after ten years' use of plain trimethoprim.

Development of trimethoprim resistance among Escherichia coli collected from urine samples in three areas in Finland was studied in 1978-1984. Three different trends of development of resistance were found: in the Turku area resistance has increased evenly during 1978-1982 from 5.4% to 10.1%, but thereafter a plateau seems to have been reached; in the Helsinki area resistance increased rapidly from 2.9% in 1980 to 11.1% in 1984, possibly due to the spread of a trimethoprim resistance transposon Tn7, which occurred significantly more often among E. coli strains in this area than in the Turku area; in the Rovaniemi area resistance has been at a plateau level, between 3.1 and 5.7%, during the whole study. No clear correlation between the consumption of trimethoprim and the level of resistance was found. The frequency of trimethoprim resistance in E. coli isolated from patients less than 65 years was 5.2% and in those isolated from patients greater than or equal to 65 years 14.7%.

DNA Transposable Elements↗
PubMed1985

Emergence of trimethoprim resistance in fecal flora.

The emergence of trimethoprim (TMP) resistance in fecal flora was compared in patients with urinary tract infection treated with TMP or TMP-sulfamethoxazole. No significant differences were found in the occurrence of TMP-resistant fecal aerobic bacteria in the two treatment groups before and after treatment.

Adolescent↗
PubMed1984

Characterization of trimethoprim resistance by use of probes specific for transposon Tn7.

Transposon Tn7 codes for resistance to trimethoprim and streptomycin. For detection of Tn7 by DNA-DNA hybridization, two recombinant plasmids were constructed. The former contained a 1-kilobase BamHI fragment and the latter contained a 4.3-kilobase EcoRI-BamHI fragment of Tn7. These DNA fragments, which did not include the drug resistance genes, were used as probes for detecting Tn7-like sequences in bacterial strains by colony hybridization. They hybridized strongly to bacterial DNA known to carry Tn7 but not to DNA known to carry transposons other than Tn7. These probes were used to study the occurrence of Tn7 in bacterial strains isolated in the Turku City Hospital in Finland. Transposon Tn7 was present in 47.2% of 199 trimethoprim-resistant enterobacteria (MIC greater than or equal to 8 micrograms/ml). Among the 69 Proteus mirabilis strains studied, 75% contained Tn7, although none of these strains transferred trimethoprim resistance in conjugation tests. The reliability of colony hybridization was further confirmed by Southern hybridization to detect the Tn7-specific 2.6-kilobase HindIII restriction fragment. Colony hybridization proved to be a sensitive and rapid method for detecting Tn7-determined sequences.

Bacteria↗
PubMed1983

Transferable trimethoprim resistance in three Finnish hospitals.

Resistance to trimethoprim in urinary tract isolates was studied in the Turku City Hospital in 1979 and 1980-81 and in the Turku and Kuopio University Central Hospitals in 1980-81. In the Turku City Hospital no changes occurred during this time in the frequency of strains highly-resistant to trimethoprim (MIC greater than 1000 mg/l) or of those in which transferable resistance was demonstrated. However, the nature of resistance has changed since 1979, when the only transferable pattern was trimethoprim-ampicillin resistance. In 1980-81 over half of the transfer-positive stains transferred only trimethoprim resistance. In the university hospitals the strains highly-resistant to trimethoprim occurred in 36.8% of strains resistant to greater than or equal to 8 mg/l. This is significantly less than 68.7% observed at the same time in the Turku City Hospital. Among the highly-resistant strains the frequency of those transferring resistance was the same in the university hospitals as in the Turku City Hospital.

Bacteria↗
PubMed1983

Hydroxyurea inhibits also the syntheses of thymine nucleotides and methionine in the cells of Escherichia coli.

Hydroxyurea not only inhibited the reduction of ribonucleotides, but also gave rise to need of exogenous methionine and thymidine for full growth in the cultures of Escherichia coli K12. In vitro the drug inhibited the formation of 5,10-methylenetetrahydrofolate by serine hydroxymethyltransferase in the cell extracts, which suggests that this reaction is a secondary target of hydroxyurea in the cells of E. coli. The syntheses of thymine nucleotides and methionine were also the most sensitive targets of hydroxylamine in the cultures of E. coli.

Escherichia coli↗
PubMedDate not supplied

Epidermolysis bullosa, pyloric atresia, and obstructive uropathy: a report of two case reports with molecular correlation and clinical management.

The epidermolysis bullosa-pyloric atresia-obstructive uropathy (EB-PA-OU) association is a rare, but well-described multisystem disease. While the prognosis at this time is still poor, an increasing number of patients are surviving to adolescence with aggressive care. It is important to understand this syndrome in order to anticipate medical complications and offer preventive strategies where possible. Prompt and expectant management of obstructive uropathy is crucial in these patients. Evidence of ureterovesicular obstruction may require bowel diversion, as excision of the obstructed ureterovesicular junction with reimplantation is often associated with a high risk of reobstruction. Many newborns succumb to sepsis or dehydration and electrolyte imbalance. Those infants who survive need close monitoring for the development of obstructive uropathy, failure to thrive, protein-losing enteropathy, respiratory compromise, and increased susceptibility to invasive infections. Once a clinical diagnosis is made, mutational analysis can confirm it and facilitate genetic counseling, as recurrence risks are 25% for this autosomal recessive condition. Mutational analysis enables direct genetic testing and accurate prenatal diagnosis. As more patients are studied, genotype/phenotype correlations may be possible.

Amino Acid Substitution↗
PubMedDate not supplied

Hemidesmosomal variants of epidermolysis bullosa. Mutations in the alpha6beta4 integrin and the 180-kD bullous pemphigoid antigen/type XVII collagen genes.

Epidermolysis bullosa (EB), a heterogeneous group of genodermatoses, is characterized by fragility and blistering of the skin, associated with characteristic extracutaneous manifestations. Based on clinical severity, constellation of the phenotypic manifestations, and the level of tissue separation within the cutaneous basement membrane zone, EB has been divided into distinct subcategories. Traditionally, these include the simplex, junctional and dystrophic variants of EB. Recent attention has been drawn to variants of EB demonstrating tissue separation at the level of hemidesmosomes, ultrastructurally recognizable adhesion complexes within the cutaneous basement membrane zone. Clinically, these hemidesmosomal variants manifest either as generalized atrophic benign epidermolysis bullosa (GABEB), EB with pyloric atresia, or EB with late-onset muscular dystrophy. Elucidation of basement membrane zone components by molecular cloning and development of mutation detection strategies have revealed that the hemidesmosomal variants of EB result from mutations in the genes encoding the subunit polypeptides of the 180-kD bullous pemphigoid antigen/type XVII collagen, the alpha6beta4 integrin, or plectin, respectively. Collectively, these data add to the understanding of the molecular complexity of the cutaneous basement membrane zone in EB, as attested by the fact that mutations in 10 different genes can underlie different variants of EB. Elucidation of mutations in different forms of EB has direct application to genetic counseling and DNA-based prenatal testing in families with EB.

Animals↗