PubMed Health⌕ Search

Biomedical subjects

E Hildebrandt

Publications and source records attributed to E Hildebrandt.

At least 19 recordsLinked to original sources
PubMed2001

Preceptors: a perspective of what works.

This article provides a perspective of clinical preceptor contributions to advanced practice nurse education. It supports quality clinical education in the face of the proliferation of academic programs, and the economics of the resulting competition. The strategies of 2 universities are used as examples of how nurse practitioner programs respond to issues such as who precepts students, how preceptors are identified, what draws preceptors to the role, and the effects of students on clinic productivity.

Humans↗
PubMed1996

Survey data collection: operationalizing the research design.

This article describes how indigenous interviewers were used to collect data about the health needs and resources in a black South African township. The survey was done during the dismantling of the apartheid political system of South Africa. The political unrest, distrust, and tension were barriers to carrying out a survey and threatened the quality of the data collection. A vulnerability of survey research is the difficulty in controlling the variables of the community and the interviewer during the process of data collection. How this survey was carried out, in this unstable setting, influenced the quality of the data and the validity and reliability of the research. The data-collection requirements were carried out in a way that was functional in the real-world setting while maintaining research standards. The criteria used for hiring interviewers and the content and delivery of training were effective in this tense, educationally disadvantaged community setting. Methods that were used to motivate and supervise interviewers were successful and are recommended for use in similar survey research.

Black or African American↗
PubMed1996

Building community participation in health care: a model and example from South Africa.

A conceptual model was developed for a community-based intervention study in a Black township in South Africa. The model shows a useful way to structure the complex role public health nurses play as they meet community health needs using a community's priorities and building toward community involvement in health and self-care. The model was applied over a 2-year period in an under-developed community of 100,00 people where the unemployment rate was over 50%, fewer than 10% of the homes had electricity, and only one-third had access to the sewage removal system. Over half of older adults interviewed were illiterate. The residents, in collaboration with the nurse researcher, gathered data, prioritized needs, and chose projects to produce solutions. The model guided activities for community empowerment through a deliberate transfer of information and expertise from the nurse to members of the community. Conceptual models or paradigms are useful to focus nursing strategies, to guide professional nursing practice, and to support interdisciplinary goals for cooperative efforts. The principles are also applicable in the United States and other developed countries as more effective ways to achieve health goals are sought.

Black or African American↗
PubMed1995

[Lipid island (xanthelasma) of the duodenal mucosa--a rarely found diagnosis and differential diagnosis].

A case report ist given on a 54-year-old patient with the so called lipid island (xanthelasma) in the duodenal mucosa. Xanthelasmas are very rarely located in the duodenal mucosa. The diagnosis and differential diagnosis of this entity are reported. The relevance of histochemistry and immunohistochemistry for differentiation of signet ring carcinoma cells in the mucosa is discussed.

Biopsy↗
PubMed1995

Regulation of calcium influx and catecholamine secretion in chromaffin cells by a cytochrome P450 metabolite of arachidonic acid.

These studies were designed to determine the role of arachidonic acid metabolites in catecholamine secretion from adrenal chromaffin cells. Inhibitors of the cytochrome P450-dependent metabolism of arachidonic acid were shown to interfere with stimulus-secretion coupling in cultured chromaffin cells. Ketoconazole (10 microM), clotrimazole (20 microM), and piperonyl butoxide (50 microM) inhibited carbachol-dependent catecholamine secretion by 44%, 83%, and 100%, respectively; histamine-dependent secretion by 25%, 60%, and 81%, and secretion induced by 59 mM KCl depolarization by 25%, 55%, and 89%. Uptake of 45Ca2+ into the cells in response to carbachol was inhibited 63% by ketoconazole, 86% by clotrimazole, and 95% by piperonyl butoxide; KCl-dependent uptake was inhibited 7%, 56%, and 85%, respectively. However, cytochrome P450 inhibitors did not inhibit catecholamine secretion when cells were stimulated with the calcium ionophores ionomycin or lasalocid. These results indicated the involvement of a cytochrome P450 product in controlling Ca2+ influx in response to membrane depolarization. Cells prelabeled with [3H]arachidonic acid formed a 3H-labeled metabolite which comigrated with authentic 5,6-epoxyeicosatrienoic (5,6-EET) acid on reverse phase and normal phase HPLC. Pretreatment with clotrimazole inhibited the production of this 3H-labeled metabolite. Addition of synthetic 5,6-EET (1 nM) to cells pretreated with piperonyl butoxide resulted in catecholamine secretion. These data suggest a role for a cytochrome P450 metabolite of arachidonic acid in agonist-stimulated catecholamine secretion.

8,11,14-Eicosatrienoic Acid↗
PubMed1994

A model for community involvement in health (CIH) program development.

Community involvement in health (CIH), a central concept in health development, is a participatory approach to health care that is organized from the perspective of the recipient. Putting CIH into practice represents a learning experience for the community, the health professionals involved and those responsible for the national climate in which this change takes place. The CIH process was operationalized over a two-year period in a black township in South Africa. A community survey identified the health needs and capacities related to the elderly, their families and their support system. Community groups and individuals, in partnership with the researcher, prioritized the needs that had been identified and then implemented four programs related to those needs. A process model was developed that provided the structure for initiating and maintaining these programs. The model helped people who were new to the community organizing to focus on general principles. It was flexible so that programs could be interpreted and implemented in the context of local culture and resources. The model was functional in guiding community nurses, lay community members and employees in health-related programs through the process of starting new programs. This approach empowered participants to move beyond only hoping for change or being puzzled by its elusiveness.

Adult↗
PubMed1991

Identification of a membrane-bound, glycol-stimulated phospholipase A2 located in the secretory granules of the adrenal medulla.

Chromaffin granule membranes prepared from bovine adrenal medullae showed Ca2(+)-stimulated phospholipase A2 (PLA2) activity when assayed at pH 9.0 with phosphatidylcholine containing an [14C]-arachidonyl group in the 2-position. However, the activity occurred in both soluble and particulate subcellular fractions, and did not codistribute with markers for the secretory granule. PLA2 activity in the granule membrane preparation was stimulated dramatically by addition of glycerol, ethylene glycol, or poly(ethylene glycol). This glycol-stimulated PLA2 activity codistributed with membrane-bound dopamine beta-hydroxylase, a marker for the granule membranes, through the sequence of differential centrifugation steps employed to prepare the granule membrane fraction, as well as on a sucrose density gradient which resolved the granules from mitochondria, lysosomes, and plasma membrane. The glycol-stimulated PLA2 of the chromaffin granule was membrane-bound, exhibited a pH optimum of 7.8, retained activity in the presence of EDTA, and was inactivated by p-bromophenacyl bromide. When different 14C-labeled phospholipids were incorporated into diarachidonylphosphatidylcholine liposomes, 1-palmitoyl-2-arachidonylphosphatidylcholine was a better substrate for this enzyme than 1-palmitoyl-2-oleylphosphatidylcholine or 1-acyl-2-arachidonyl-phosphatidylethanolamine, and distearoylphosphatidylcholine was not hydrolyzed.

Acetophenones↗
PubMed1990

Novel localization of a G protein, Gz-alpha, in neurons of brain and retina.

Recently, a cDNA coding for a novel G protein alpha-subunit, Gz-alpha, was isolated from a human retinal cDNA library and shown by Northern blot analysis to be expressed at high levels in neural tissues. We have prepared affinity-purified antibodies specifically directed against synthetic Gz-alpha peptides and employed immunohistochemical methods to map the localization of Gz-alpha in human, bovine, and murine retina and brain. By light microscopy, Gz-alpha was localized to the cytoplasm of neurons, with predominant reactivity in ganglion cells of the retina, Purkinje cells of the cerebellum, and most neurons of the hippocampus and cerebral cortex. Reactivity was confined to perikaryon, dendrites, and a very short segment of proximal axons, except for the retinal ganglion cells, in which the axons in the nerve fiber layer showed intense Gz-alpha immunoreactivity proximal to the lamina cribrosa. Pre-embedding immunoelectron microscopy demonstrated the presence of focal Gz-alpha immunoreactivity on the nuclear membranes, endoplasmic reticulum, and plasma membranes of Purkinje cell perikarya and in association with microtubules in their proximal dendrites. Subcellular fractionation studies confirmed the association of Gz-alpha with plasma and intracellular membranes. The localization of Gz-alpha and its unique amino acid sequence suggest that it may have a specialized function in neural tissues.

Animals↗
PubMed1990

[Results of sonographically-guided percutaneous procedures as therapy of liquid-filled space-occupying lesions in acute abdomen].

In the period from 1985 emergency sonographic study has been performed in 56 patients. In 44 cases we found intraabdominal abscesses, in 5 liver cysts with internal bleeding, in 5 postoperative lymphatic cysts, and in 2 cases loculated pleural empyemas. In 35 patients ultrasound guided therapeutic procedures were performed; there were 13 punctures (some repeated) and 22 drainages. In 29 patients no further surgical treatment was necessary. The over all success rate was 82.9%. One patient developed bacteremia after percutaneous drainage and an other developed subcutaneous abscess (complication rate: 5.7%). When abscesses are sufficiently drained no antibiotic therapy is needed.

Abdomen, Acute↗
PubMed1989

Phosphoamino acid analysis of protein immobilized on polyvinylidene difluoride membrane.

The direct analysis of phosphorylated proteins bound to polyvinylidene difluoride membrane (PVDFm) has been examined. Use of 14C-methylated marker proteins demonstrated that proteins electroblotted on PVDFm were quantitatively retained through a series of test conditions, which included 1 M hydroxylamine (25 degrees C, 30 min), 0.1 M NaOH (37 degrees C, 30 min), 0.1 M HCl (55 degrees C, 2 h), and 6 U/ml alkaline phosphatase (pH 9.5, 37 degrees C, 24 h). Approximately half the protein remained bound following 2-h treatment in 1 M KOH (55 degrees C). The same series of test conditions were employed to assess the stability of phosphorylated residues in 32P-labeled protein immobilized on PVDFm, in order to assign them as carboxyl-,N-, or O-linked groups. The properties of phosphorylated proteins as determined by this method were comparable to the properties that have been reported for soluble proteins. Use of the PVDFm immobilization step affords simplification of the experimental procedures and permits rapid, quantitative sample recovery using submicrogram quantities of protein. Further, the PVDFm-bound phosphoproteins could be subjected to partial acid hydrolysis directly on the membrane and required no further purification for subsequent identification of the labeled phosphohydroxyamino acids. Definitive identification of labeled phosphoserine residues in histone, phosphoserine and phosphothreonine residues in myelin basic protein and insulin receptor, and phosphotyrosine residues in autophosphorylated insulin receptor was accomplished with as little as 0.2 nCi in about 50 ng of phosphorylated protein.

Amino Acids↗
PubMed1988

Measurement of branched-chain alpha-keto acid dehydrogenase flux rates in perfused heart and liver.

The methods described here represent a flexible set of procedures for investigating the metabolism of the branched-chain alpha-keto acids and other substances in perfused organs, notably the rat heart and liver. These procedures have been used to investigate many aspects of the metabolism of the branched-chain alpha-keto acids not discussed here, such as the effects on branched-chain alpha-keto acid metabolism by exposure to alpha-adrenergic agents, by inhibition of the monocarboxylate translocator, and by the coinfusion of other metabolites.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1987

Role of activation of myocardial branched-chain 2-oxo acid dehydrogenase complex in the regulation of leucine decarboxylation during cardiac work in vitro.

The oxidative decarboxylation of L-[1-14C]leucine was measured in the isolated perfused rat heart under both working and non-working conditions. Stimulation of decarboxylation of the labelled substrate was observed in working hearts as cardiac work was increased, and in Langendorff hearts upon increasing the coronary flow rate. The rate of L-[1-14C]leucine decarboxylation was significantly higher (P less than 0.05) in hearts working against moderate afterload pressure when compared to Langendorff hearts perfused at a matching coronary flow rate. The rate of release of 4-methyl-2-oxo[1-14C]pentanoate to the perfusate was high in Langendorff hearts, and was unaffected by changes in coronary flow. In contrast, perfusate levels of 14C-labelled 4-methyl-2-oxopentanoate decreased significantly upon the establishment of the working condition (P less than 0.05). These findings suggested an enhancement in the efficiency of the decarboxylation of the 2-oxo acid in response to cardiac work. The amount of branched-chain 2-oxo acid dehydrogenase complex present in the active form was measured in freeze-clamped hearts. Cardiac work resulted in a rapid activation of the complex (P less than 0.02) within 5 min of work when compared to control Langendorff hearts perfused at matching coronary flow rates. To a lesser extent, increasing the coronary flow rate in Langendorff-perfused hearts also led to activation of the enzyme complex. These studies suggest the following: a) L-leucine oxidation in myocardial tissue can be accelerated by exercise as it is in other tissues; b) this regulatory response can be evoked by the contractile activity of the heart itself, independent of contributions by circulating factors or nervous stimuli; and c) regulation of the activity state of the branched-chain 2-oxo acid dehydrogenase complex is involved in the mechanism by which metabolic flux through this pathway is controlled during cardiac work.

3-Methyl-2-Oxobutanoate Dehydrogenase (Lipoamide)↗
PubMed1987

Ubiquitin has intrinsic proteolytic activity: implications for cellular regulation.

Ubiquitin is a protein of 76 amino acids found in every eukaryotic cell. Although ubiquitin is implicated in ATP-dependent nonlysosomal protein degradation and is also conjugated to specific cellular proteins, the role played by ubiquitin in cellular events has not been defined. We report that purified ubiquitin has intrinsic proteolytic activity and demonstrate that this activity is comparable to that of other well-characterized proteases. Monoclonal antibodies specific to ubiquitin inhibit proteolysis. Ubiquitin has protease activity over a broad pH range with an optimum at pH 8.0. It is stimulated by Ca2+ and is inhibited by high concentrations of phenylmethylsulfonyl fluoride and diisopropyl fluorophosphate. Ubiquitin will cleave proteins at a limited number of sites. We propose that the ubiquitination of a protein can convert that protein into an ad hoc specific protease and models are presented as to how this can play a role in regulating a variety of cellular events.

Antibodies, Monoclonal↗
PubMed1984

Indirect inhibition of vitamin K epoxide reduction by salicylate.

Salicylate antagonizes the vitamin K-dependent biosynthesis of clotting factors in the rat and produces an elevation of the ratio of vitamin K epoxide to vitamin K in the liver. Vitamin K epoxide is reduced to vitamin K by a vitamin K epoxide reductase, and 1 mM salicylate was required to cause a 50% inhibition of the dithiothreitol-dependent in-vitro reduction of vitamin K epoxide by this enzyme. This enzyme was, however, inhibited 50% by as little as 70-80 microM salicylate when reducing equivalents for the reaction were furnished by endogenous cytosolic reductants. This effect on the cytosolic reductant supply was shown to be unrelated to a previously demonstrated inhibition of DT-diaphorase by salicylate. The concentrations of salicylate at which significant inhibitory effects are exerted in-vitro (50-100 microM) are below the 200 microM levels observed in the livers of rats given an anticoagulating dose of salicylate.

Animals↗
PubMed1983

Formation of hydroxyvitamin K by vitamin K epoxide reductase of warfarin-resistant rats.

A new metabolite of vitamin K, 2(3)-hydroxy-2,3-dihydro-2-methyl,3-phytyl-1,4-naphthoquinone (hydroxyvitamin K), has been identified as a product of vitamin K epoxide metabolism in hepatic microsomes from warfarin-resistant rats, but not in those derived from normal rats. The structure was determined by comparison of the high performance liquid chromatography retention times, UV, IR, CD, and mass spectra of the unknown with chemically synthesized standards. Alterations in the formation of hydroxyvitamin K occur in parallel with alterations in total vitamin K epoxide conversion with respect to reaction time, extent of reaction, detergent stimulation, and inhibition by warfarin. Thus, hydroxyvitamin K appears to be a product of the warfarin-resistant vitamin K epoxide reductase. It is neither a substrate nor an inhibitor of epoxide reduction. Hydroxyvitamin K is formed from both enantiomers of racemic vitamin K epoxide with little stereoselectivity for the configuration of either the oxirane ring or the phytyl side chain. The reaction is stereospecific; however, the biologically formed (+)-vitamin K epoxide yields exclusively (+)-3-hydroxyvitamin K. Observation of this product is discussed as a key to understanding the normal reaction mechanism of the enzyme.

Animals↗
PubMed1977

[Radioimmunological determination of aldosterone in the serum. New method for the localization of aldosteronism].

It is described a radioimmunologic method for the determination of aldosterone in the plasma and the urine. The method possesses a high specifity, so that a chromatographic prepurification can be given up. The achieved sensitivity allows an analysis in 0.2 ml plasma. This radioimmunoassay can be used for the determination of the aldosterone concentration in the blood after side-separated taking from the adrenal veins by means of the catheter technique. With this a localisation diagnostics of the aldosteronoma is possible.

Aldosterone↗