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Biomedical subjects

A Molenaar

Publications and source records attributed to A Molenaar.

17 recordsLinked to original sources
PubMed2004

Mastitis increases mammary mRNA abundance of beta-defensin 5, toll-like-receptor 2 (TLR2), and TLR4 but not TLR9 in cattle.

Coordination of the primary defense mechanisms against pathogens relies on the appropriate expression of pathogen recognition receptors (PRRs) triggering the early release of effector molecules of the innate immune system. To analyze the impact of this system on the counteraction of infections of the mammary gland (mastitis), we characterized the bovine gene encoding the key PRR Toll-like receptor 9 (TLR9) and mapped its precise position on chromosome BTA22. The sequence information was used to establish real-time PCR quantification assays to measure the mRNA abundances of TLR9, TLR2, and TLR4 together with those of beta-defensin 5 (BNBD5), an early bactericidal effector molecule of the innate system, in healthy and infected mammary glands. Mastitis strongly increased (4- to 13-fold) the mRNA abundances of all of these genes except TLR9. Slight subclinical infections already caused a substantial increase in the copy numbers, though they did so the least for TLR9. Induction was not systemic, since mRNA abundance was low in uninfected control quarters of the udder but high in the severely infected quarters of the same animal. The number of TLR2 copies correlated well with those of TLR4, indicating coordinated regulation of these two PRRs during infection of the udder. Their coordinated regulation explains our unexpected observation that pure Staphylococcus aureus infections caused a strong increase also in TLR4 mRNA abundance. In situ hybridizations revealed that BNBD5 is expressed predominantly in the mammary epithelial cells (MEC) of the infected gland. Our data therefore suggest a significant contribution of the innate immune system to counteract mastitis and attribute a prominent effector function to the MEC.

Amino Acid Sequence↗
PubMed2000

Molecular characterization of STAT5A- and STAT5B-encoding genes reveals extended intragenic sequence homogeneity in cattle and mouse and different degrees of divergent evolution of various domains.

The STAT transcription factors form a family of signal transducers and activators of transcription. We sequenced the bovine STAT5B cDNA and both STAT5-encoding genes, STAT5A and STAT5B, representing the first complete description of any STAT5-encoding gene. DNA fiber FISH hybridization revealed that the genes reside only 40 kbp apart on BTA19. Both genes are segmented into 19 exons and all but two of the homologous exons are of equal size. The genes harbor a central block of nearly identical DNA sequence (97.5% sequence identity over 3373 bp), spanning from intron 5 to intron 9. Isolation and sequencing of the homologous segments from mouse revealed the same unusually high degree of intronic sequence conservation in these segments of the murine STAT5-encoding genes. However, the respective sequences are completely divergent between the two species. A comparison of the inter- and intragenic cDNA sequence preservation at nonsynonymous sites reveals that the DNA-binding domain is under the strongest selection pressure for both intergenic and factor-specific intragenic sequence preservation. The so-called "SH3" segment of the linker domain, in contrast, shows species-specific sequence identity in all but one amino acid residues in both factors, in cattle, human, and mouse. This indicates that the same species-specific selection pressure occurs on the linker domain from both factors, STAT5A and STAT5B. Thus, the comparison of evolutionary selection pressures resting on various domains suggests that the DNA-binding domain might contribute to differential DNA binding of STAT5A and STAT5B factors, while both might interact equally well with other cellular factors through a segment of the linker domain.

Amino Acid Sequence↗
PubMed1988

The depressed nasofrontal angle in aesthetic rhinoplasty.

Certain patients seeking cosmetic rhinoplasty present with a so-called depressed nasofrontal angle. In this condition, the most careful part of the nasal bone is underdeveloped. This gives the illusion of a nasal hump. Complete removal of this hump will create a hypoplastic nose. Partial reduction of the hump and augmentation in the nasofrontal area are indicated in these patients. Autogenous material is preferable for this purpose. A number of patients are presented with illustration of the technique.

Adult↗
PubMed1985

Plasma 1.25-dihydroxyvitamin D concentrations in preterm infants.

1.25-Dihydroxyvitamin D concentrations were measured in 10 preterm infants (mean gestational age 29 weeks, range 26-32; mean birthweight 1226 g, range 980-1700). Total parenteral nutrition was begun after birth and partial enteral feeding was started at 1 week of age. Total enteral feeding was achieved at a mean age of 26 days (range 16-47). The daily vitamin D3 intake was about 400 I. U. No clinical, chemical or radiological signs of rickets were observed. The mean 1.25-dihydroxyvitamin D concentration +/- SEM was 103.2 +/- 24.0 pmol/l at 1 week (range 9.6-252.0), 141.6 +/- 26.4 at 3 weeks (range 31.2-324.0), 153.6 +/- 21.6 at 6 weeks (range 67.2- 256.8), 165.6 +/- 24.0 at 9 weeks (range 74.4-307.2) and 153.6 +/- 21.6 at 12 weeks (range 76.8-268.8) postnatal age. The mean values at 6, 9 and 12 weeks were significantly higher (p resp. less than 0.01, less than 0.002 and less than 0.005) than in adults (88.8 +/- 7.2; n = 27). 1.25-Dihydroxyvitamin D concentrations were highly variable and did not correlate with 25-hydroxyvitamin D concentrations, plasma calcium and phosphorus concentrations and plasma alkaline phosphatase levels, nor with illness nor postnatal age. The data demonstrate that preterm infants are capable of producing high plasma levels of 1.25-dihydroxyvitamin D.

Alkaline Phosphatase↗