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P Burkhardt

Publications and source records attributed to P Burkhardt.

9 recordsLinked to original sources
PubMed2000

11Beta-hydroxysteroid-dehydrogenase isoforms: tissue distribution and implications for clinical medicine.

11Beta-hydroxylation is essential for glucocorticoid and mineralocorticoid activity of a steroid. The enzyme catalyzing this reaction is termed 11beta-hydroxysteroid-dehydrogenase (11beta-HSD). Two isoenzymes of 11beta-HSD have been characterized in human tissues. Whereas 11beta-HSD-I works mainly as a reductase, 11beta-HSD-II only functions as an oxidizing (inactivating) enzyme for physiological glucocorticoids. Thus, the tissue distribution of both enzymes plays a crucial role for the specific glucocorticoid status of an organ. This review summarizes our knowledge of tissue distribution of both 11beta-HSD isoenzymes, their physiological function and pathophysiological role in certain clinical abnormalities, and their relevance to the metabolism of synthetic glucocorticoid and mineralocorticoid compounds.

11-beta-Hydroxysteroid Dehydrogenase Type 2↗
PubMed1996

Nurse midwifery. Advanced practice nursing?

This article traces the roots and history of nurse-midwifery in the United States in order to demonstrate the reality of midwifery as a profession in its own right. From its beginnings in the late 1920s, the profession has gradually evolved from its clear roots in nursing to an identity of its own expressed through its professional organization, the American College of Nurse-Midwives. A review of other countries' experiences with midwifery reflect much of the U.S. process and results. The future challenge for both professions is to determine how they can exist in harmony, recognizing that they are complementary roles.

Canada↗
PubMed1976

[Treatment of 10 cases of symptomatic Paget's disease with etidronate (EHDP)].

10 patients with active symptomatic Paget's disease of bone have been treated for 6 months with disodium etidronate (EHDP) at a dose of 20 mg/kg/day. A statistically significant fall in the serum levels of alkaline phosphatase and urinary hydroxyproline was observed. However, only 2 patients experienced a significant reduction of bone pain. 6 patients were partially improved and 2 patients showed no change. Iliac crest biopsies after treatment demonstrated dimunution of the abnormal structure of the pagetic bone, but also a considerable increase in unmineralized osteoid borders. The future potentialities for treatment of Paget's disease are discussed.

Aged↗
PubMedDate not supplied

Metabolism of synthetic corticosteroids by 11 beta-hydroxysteroid-dehydrogenases in man.

The presence of an 11 beta-hydroxyl group is essential for the anti-inflammatory and immunosuppressive effects of glucocorticoids. Interconversion of the 11 beta-hydroxyl into the corresponding 11 beta-keto group and vice versa by 11 beta-hydroxysteroid-dehydrogenase (11 beta-HSD) may thus play a pivotal role in the efficacy of these steroids. Therefore, we have compared the metabolism of the endogenous glucocorticoid cortisol (F) with that of synthetic 9 alpha-fluorinated steroids by 11 beta-HSDs in humans in vivo and in vitro. Whereas 30% of the free steroids in urine after oral administration of 5 mg of F is F itself and 70% the inactive keto-product cortisone (E), the urinary excretion of an identical dose of oral 9 alpha-fluorocortisol (9 alpha FF) is 90% 9 alpha FF and 10% inactive 9 alpha-fluorocortisone (9 alpha FE). Kidney slices similarly convert F much faster to E than 9 alpha FF to 9 alpha FE; conversely, renal 11 beta-reduction of 9 alpha FE to 9 alpha FF is much more effective than that of E to F. Kinetic analyses in human kidney cortex microsomes prove that the preference of fluorinated steroids for reduction in human kidney slices is catalyzed by 11 beta-HSD type II: the NADH-dependent conversion of 11-dehydro-dexamethasone (DH-D), another fluorinated steroid, to dexamethasone (D) is very effective (high affinity, high Vmax), whereas reduction of E to F is very slow. In human liver microsomes (11 beta-HSD type I), nonfluorinated (E) and fluorinated 11-dehydrosteroids (DH-D) are both reduced to their corresponding active 11-hydroxyderivatives but with a Michaelis-Menten constant about 20-fold higher than for kidney microsomes (11 beta-HSD-II). Our results suggest that the decreased renal 11 beta-oxidation of 9 alpha-fluorinated steroids may offer pharmacokinetic advantages for renal immunosuppression. Furthermore, administration of fluorinated 11-dehydrosteroids is a new and exciting idea in glucocorticoid therapy in that small amounts of oral DH-D may pass the liver largely unmetabolized (11 beta-HSD-I has low affinity for such steroids) and may then be activated to D by high-affinity 11 beta-HSD-II, thus allowing selective immunosuppression in organs expressing 11 beta-HSD-II (kidney and colon).

Adrenal Cortex Hormones↗
PubMedDate not supplied

Findings from the American College of Nurse-Midwives' annual membership survey, 1995-1999.

American College of Nurse-Midwives (ACNM) membership data collected from 1995-1999 offer a description of the evolution of the profession of midwifery, as shown in the characteristics of certified nurse-midwives and certified midwives, including basic demographics, practice characteristics, and employment components. During the period studied, slight increases were noted in age, number of years in practice, salary, and education level. Although the overall proportion of midwives of color did not change appreciably during the 5-year period, the absolute numbers of culturally diverse midwives increased. Student midwives were found to be younger and more culturally diverse than they were in the early 1990s. Data about midwifery practice provide valuable information to health care managers, educators, policy makers, legislators, and professional organizations, which may guide allocation of resources and reflect how members of the professions can influence access to health care for women and their families.

Adult↗