Biomedical subjects

D A Haas

Publications and source records attributed to D A Haas.

41 records · Page 3Linked to original sources

PubMed1987

Hypothalamic corticotropin-releasing factor immunoreactivity is reduced during induction of pituitary tumors by chronic estrogen treatment.

The role that estrogen plays in the regulation of corticotropin-releasing factor (CRF) is not known. A radioimmunoassay specific for rat CRF was utilized to measure the CRF-like immunoreactivity (CRF-ir) in the hypothalamus of ovariectomized rats treated with estradiol for periods up to 12 weeks. Compared to ovariectomized controls, estradiol treatment resulted in significantly reduced CRF-ir after 3 and 12 weeks, although no significant change was seen after 8 weeks. Anterior pituitary (AP) weight was greatly increased by estradiol treatment at all time points studied. Bromocriptine treatment for the last 3 weeks of the 12-week period, or removal of estradiol for 3 weeks after 9 weeks of treatment did not reverse the changes in CRF-ir even though significant regression of tumor size was achieved. There was no correlation between AP weight and CRF-ir in individual animals. These data show that chronic treatment with estrogen reduced hypothalamic CRF-ir content. Neither a direct estrogenic effect or an indirect effect mediated through alterations in the adenohypophysis could be ruled out.

Animals↗

PubMed1987

A highly diverged beta 1 exon in the DR region of the human MHC: sequence and evolutionary implications.

The DR subregion of the human major histocompatibility complex from a DR4 haplotype includes the well-characterized DR alpha, DR4 beta, DR(MT3)beta psi genes. In addition, the region between the DR alpha and the proximal DR(MT3)beta contains several copies of conserved DR beta-related sequences. These repeated elements, numbered II, III, and IV, include the DR beta signal sequence and a region located further upstream. Further examination of these conserved sequences showed that DR beta first intron sequences are present at the 3' ends of these repeats. Progressively longer portions of the DR beta first intron are conserved from repeat II to repeat IV, producing a gradient of conservation. The most complete repeat element of repeats II, III, and IV is associated with a lone beta 1 exon (DR beta 1). Upon sequencing, DR beta 1 was found to contain several deleterious mutations, indicating that it is nonfunctional. DR beta 1 has accumulated a large number of replacement substitutions and mutations at positions which are invariant in beta 1 domains from expressed DR beta genes: 77.8% of the nucleotide substitutions were replacement substitutions, and 41.5% of the amino acids at invariant positions have been altered. Calculations based on these figures suggest that DR beta 1 may have become inactive approximately 25 million years ago. There are, however, two histidine residues within a variable region which are unique to DR beta 1 and the DR4 beta gene, suggesting that they represent a gene pair which probably evolved by duplication of a single DR beta chain gene.

Amino Acid Sequence↗

PubMedDate not supplied

Drug use for the pregnant or lactating patient.

The dental patient who is pregnant or lactating may require management involving the administration or prescription of drugs. The approach of completely avoiding all drugs may not permit appropriate treatment of the patient and most often is not warranted. This article reviews the current considerations in the use of drugs in the dental patient who is either pregnant or lactating. The safety of the local anesthetics, vasoconstrictors, analgesics, antimicrobials, and sedatives used in dentistry is discussed.

Analgesics↗

PubMedDate not supplied

Comparison of articaine and prilocaine anesthesia by infiltration in maxillary and mandibular arches.

Claims that labial infiltration of the local anesthetic articaine HCl (Ultracaine DS) results in anesthesia of mandibular pulpal as well as maxillary and mandibular lingual soft tissue have never been scientifically substantiated. The aim of this investigation was to evaluate these claims, by comparing articaine to a standard anesthetic, prilocaine HCl (Citanest Forte). To investigate this, a double blind, randomized study was conducted in healthy adult volunteers. In each volunteer, the ability to induce maxillary and mandibular anesthesia following labial infiltration with articaine was compared to prilocaine given contralaterally. Anesthesia was determined by measuring sensation to electrical stimulation at the tooth, labial and lingual soft tissue for each of the 4 non-carious, non-restored, canines. Results showed that mandibular canine pulpal anesthesia had a success rate of 65% for articaine and 50% for prilocaine. Success rates for palatal and lingual anesthesia averaged 5% for each agent. As determined by chi-square analysis, no statistically significant differences were found between articaine and prilocaine for any tissue at any of the 6 sites (P greater than 0.05). A time-course assessment also failed to demonstrate a difference between the two drugs. Therefore these data are not consistent with superior anesthesia efficacy being produced by articaine at any site, including the mandibular pulpal, lingual or maxillary palatal tissues, in the canine teeth studied.

Administration, Buccal↗

PubMedDate not supplied

Antimicrobial resistance: dentistry's role.

The resistance of bacteria, fungi and viruses to antimicrobials is increasing rapidly, with deleterious consequences. Dentistry's role in this development is unclear, because the necessary information has not yet been collected. Nevertheless, dentists should recognize that it is essential to use antimicrobials in an appropriate and responsible manner, both to treat infection effectively, and to minimize the likelihood that the bacteria in the general population will develop resistance to antimicrobials. The purpose of this article is to make dentists aware of the concerns raised by antimicrobial resistance, and how it can be avoided.

Anti-Bacterial Agents↗