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Biomedical subjects

D Kowalski

Publications and source records attributed to D Kowalski.

At least 55 records · Page 3Linked to original sources
PubMed1989

[Triiodothyronine (T3) and thyroxine (T4) levels in patients with bronchial asthma].

In 212 patients with bronchial asthma and 115 healthy controls the serum levels of T4 and T3 were determined. In patients not treated with corticosteroids a statistically significant rise of T3 and fall of T4 were noted. These changes were non-significantly smaller in the patients with pronounced dyspnea . During long-term corticoid++ therapy a tendency was observed for normalization of these changes.

Adult↗
PubMed1989

[Parathyroid hormone and blood pressure in patients with chronic renal failure treated by repeated hemodialysis].

In 36 patients with chronic renal failure treated with repeated haemodialyses the relationship was studied between the level of the C-terminal fragment of the parathyroid hormone in the serum and arterial blood pressure. Depending on the value of the concentration of this C-fragment the patients were divided into three groups: I with concentration below 200 pg/ml, II with concentration 2000-5000 pg/ml, III over 500 pg/ml. In the first group a statistically significant correlation was found between the concentration of the C-terminal fragment of the hormone in the serum and the values of systolic arterial pressure (r = 0.687; p less than 0.05) and diastlic pressure (0 = 0.637; p less than 0.05).

Blood Pressure↗
PubMed1989

[Usefulness of determining serum levels of prolactin in women with menstruation disorders].

In 173 women with oligomenorrhea or amenorrhea, serum level of prolactin (PRL) was determined by radioimmunoassay method. In 22 cases (12.7%) the concentration of PRL was above 15 ng/ml. From the above women in 9 cases (5.2%) of all examined patients pituitary microadenoma was diagnosed. In 1 patient with pituitary microadenoma, coexisting partially empty sella was diagnosed. The mean basal PRL concentration in women with menstruation disturbances without hyperprolactinemia (group I) was found to be 7.1 +/- 3.1 ng/ml while the women with hyperprolactinemia without pituitary microadenoma (group II) was 32.9 +/- 5.8 ng/ml. In women with diagnosed pituitary microadenoma (group III) PRL concentration was 131.8 +/- 47.7 ng/ml. The group II and III demonstrated statistically significant increase of serum prolactin level in comparison to group I. Moreover in comparison with group I, statistically significant reduction of serum level of FSH, LH and estradiol 17 beta was confirmed in group with pituitary microadenoma. In group II significant decrease of serum concentration of LH and estradiol 17 beta was stated as well as lack of significant difference in serum level of FSH, in comparison to group I.

Adenoma↗
PubMed1988

The ease of DNA unwinding as a determinant of initiation at yeast replication origins.

We have localized the DNA sequence that facilitates unwinding of a yeast replication origin, the H4 ARS. The readily unwound sequence lies adjacent to the previously characterized consensus core sequence of the ARS. Unwinding is detected through the formation of a single-strand-specific nuclease hypersensitive site in H4 ARS mutant derivatives present on supercoiled plasmids. Linker-scanning and linker-deletion derivatives exhibit wild-type nuclease hypersensitivity and ARS function, while large external deletions reduce or eliminate nuclease detectable unwinding and origin function. ARS unwinding and origin function can be rescued in the deletion mutants by inserting a biologically unrelated sequence with DNA unwinding properties similar to a functional ARS. The data clarify the nature of DNA sequence requirements in the ARS by suggesting that small substitutions, insertions, and deletions are tolerated in the region flanking the consensus core sequence because they do not significantly alter the unwinding properties of the region.

DNA Mutational Analysis↗
PubMed1988

Stable DNA unwinding, not "breathing," accounts for single-strand-specific nuclease hypersensitivity of specific A+T-rich sequences.

A long A+T-rich sequence in supercoiled pBR322 DNA is hypersensitive to single-strand-specific nucleases at 37 degrees C but not at reduced temperature. The basis for the nuclease hypersensitivity is stable DNA unwinding as revealed by (i) the same temperature dependence for hypersensitivity and for stable unwinding of plasmid topoisomers after two-dimensional gel electrophoresis, (ii) preferential nuclease digestion of stably unwound topoisomers, and (iii) quantitative nicking of stably unwound topoisomers in the A+T-rich region. Nuclease hypersensitivity of A+T-rich sequences is hierarchical, and either deletion of the primary site or a sufficient increase in the free energy of supercoiling leads to enhanced nicking at an alternative A+T-rich site. The hierarchy of nuclease hypersensitivity reflects a hierarchy in the free energy required for unwinding naturally occurring sequences in supercoiled DNA. This finding, along with the known hypersensitivity of replication origins and transcriptional regulatory regions, has important implications for using single-strand-specific nucleases in DNA structure-function studies.

Base Sequence↗
PubMed1987

Yeast regulatory sequences preferentially adopt a non-B conformation in supercoiled DNA.

Mung bean nuclease was used to probe for DNA unwinding in torsionally-stressed chimeric plasmids containing two micron plasmid sequences and the yeast LEU2 gene in a pBR322 vector. The yeast sequences are cleaved at only two sites, both of which map to regulatory regions: (1) the autonomously replicating sequence (ARS), an origin of DNA replication, of the two micron plasmid and (2) the transcription terminator region of the LEU2 gene. Nucleotide level analysis of the nuclease cleavage pattern shows that an A + T-rich structure, distinct from other non-B DNA conformations, is recognized. A computer analysis reveals that A + T content alone is not sufficient to explain the preferential occurrence of the A + T-rich structure in the ARS over other sequences of equal A + T content. The A + T-rich structure detected in the ARS maps to sequences required for DNA replication. Our findings demonstrate the DNA conformational flexibility of certain yeast regulatory regions and provide support for the hypothesis that the A + T-rich sequence in the ARS plays a role in DNA unwinding during the initiation of DNA replication.

Base Composition↗
PubMed1986

Altered DNA conformations in the gene regulatory region of torsionally-stressed SV40 DNA.

We used mung bean nuclease to probe the SV40 genome for DNA unwinding and unpairing. Cleavage occurred at a limited number of specific sites in supercoiled, but not relaxed DNA. The number and location of cleavage sites depended upon Mg2+ concentration. Without Mg2+, cutting occurred mainly in one early denaturation region located 3' to the t antigen gene and within the T antigen gene intron. With Mg2+, cleavage occurred at a number of alternative sites in the genome. Certain Mg2+ concentrations favored cleavage in the gene regulatory region. These cleavages were mapped at single nucleotide resolution and occurred in both transcriptional enhancers and upstream from the start of major late gene transcription. The cleavages occurred between 5 bp inverted repeat sequences, consistent with the recognition of unusually small cruciform structures.

Animals↗