Biomedical subjects

B E Carter

Publications and source records attributed to B E Carter.

10 recordsLinked to original sources

PubMed1997

Expanding nursing informatics knowledge through cirriculum development: a collaborative faculty practice model.

In 1992 an informatics faculty practice model was implemented between a major teaching hospital and a Melbourne university. This arrangement was characterised by the provision of a mutually beneficial exchange of experiences and information between the participant clinician and academic. By using such a conjoint faculty practice model it has been found that many informatics problems can be addressed. Over the past three years the model has been evaluated through a longitudinal study. Investigations have included monitoring curriculum change, program evaluation and evaluation of participant professional outcomes. Survey results are presented and the specific elements that have made this model successful are described.

Curriculum↗

PubMed1992

delta-Aminolevulinic acid dehydratase: effects of succinylacetone in rat liver and kidney in an in vivo model of the renal Fanconi syndrome.

Succinylacetone (SA) is a known inhibitor of the heme biosynthetic pathway in liver. We have demonstrated previously the SA enhancement of delta-aminolevulinic acid dehydratase (ALAD) in renal tubules, while this enzyme is known to be impaired by SA in the liver. The present studies, based on in vivo treatment of animals with SA, show equivalent degree of inhibition of specific ALAD activity in liver and kidney. Both tissues evidenced an ability to restore enzyme activity with time, the recovery occurring much more slowly in kidney than in liver. The discrepant in vitro and in vivo effect of SA on renal ALAD may be due to differences between a direct inhibitor-enzyme interaction and inhibitor actions in the living cell, respectively. Persistent tissue levels of SA, consistent with demonstrated SA in plasma and urine, might account for continuing inhibition, with the greatest tissue accumulation in kidney where the substance must be cleared for excretion.

Animals↗

PubMed1991

Renal heme metabolism in hereditary tyrosinemia: use of succinylacetone in rat renal tubules.

Succinylacetone (SA), a metabolic end-product found in urine from individuals with hereditary tyrosinemia and associated renal Fanconi syndrome and a known inhibitor of hepatic 5-aminolevulinic acid dehydratase (ALAD), has been used to study heme metabolism in isolated rat renal tubules. Heme biosynthetic porphyrin precursors are increased selectively in the presence of 4 mmol/1 SA. Total porphyrin content of the tubules are increased approximately 2-fold, while both ferrochelatase and heme oxygenase activities remain unaffected by SA. Nonetheless, total heme content is reduced, as was incorporation of radioactive label from amino[14C]levulinic acid. Cytochrome P-450 content remained unaffected. Impairment of iron uptake and/or transport within the cell or enhancement of heme catabolism via a non-heme oxygenase-dependent pathway could explain the observations.

Amino Acid Metabolism, Inborn Errors↗

PubMed1991

Succinylacetone effects on renal tubular phosphate metabolism: a model for experimental renal Fanconi syndrome.

Phosphaturia is a prominent component of the renal Fanconi syndrome associated with the autosomal recessive disease, hereditary tyrosinemia. Succinylacetone (SA), the metabolic by-product of the enzyme deficiency, can be shown to produce multiple adverse effects on rat renal epithelial cell function in vitro. With the use of this compound, we have examined its interaction with Pi handling by the renal tubule cell in order to form a basis for understanding the effects of endogenously generated SA in causing phosphaturia in the genetically affected kidney. In this report we have shown complete inhibition of sodium-dependent phosphate uptake by renal brush border membrane vesicles, decreased ATP production by the SA-exposed renal tubule, and reversible inhibition of State 3 oxidation of glutamate by isolated renal mitochondria. We conclude that the phosphaturia observed in hereditary tyrosinemia results from multiple metabolic effects of SA on the renal tubule which are additive and lead to intracellular Pi depletion and diminished ATP production.

Adenosine Triphosphate↗

PubMed1990

On rat renal aminolevulinate transport and metabolism in experimental Fanconi syndrome.

Hereditary tyrosinemia, an autosomal recessive disease of human infants, is characterized by severe liver disease, a renal Fanconi syndrome, and urinary excretion of large quantities of both aminolevulinate (ALA) and succinylacetone (SA). The latter is a metabolic end-product of tyrosine catabolism in affected individuals, produced by both liver and kidney, and is a potent inhibitor of aminolevulinate dehydratase (ALAD) in liver. This inhibition has been assumed to result in release of large amounts of aminolevulinate from liver into the circulation, with subsequent urinary excretion. In the present report we examine the effects of succinylacetone on rat renal cortical tubular handling of ALA and the relationship to tubular heme content, demonstrating a marked impairment of each. In contrast, maleic acid was found to have no effect on either renal ALAD or heme content. Thus, we conclude that renal handling of ALA in SA-treated rat renal cortex may indicate a contribution by the kidney to the increased net ALA excretion observed in hereditary tyrosinemia.

Amino Acid Metabolism, Inborn Errors↗

PubMed1990

delta-Aminolevulinic acid dehydratase: is there a form unique to renal cortex?

Succinylacetone (SA) is known to be a potent inhibitor of delta-aminolevulinic acid dehydratase (ALAD) in the liver. We have examined the effects of SA on the rat renal cortical enzyme, our observations indicating very different behaviour of renal versus hepatic ALAD with SA treatment. While the temperature response of ALAD in both tissues was similar, addition of 4 mmol/l SA inhibited liver ALAD at 37 and 55 degrees C and enhanced renal ALAD activity 2- to 3-fold at each temperature. This increase in renal ALAD was progressive with SA concentrations form 1 to 10 mmol/l. A pH titration curve for both liver and kidney ALAD showed the hepatic enzyme to have a single pH optimum, while the renal enzyme had two, each of which was distinct from that in liver. Kinetic studies with and without 4 mmol/l SA over a 50-fold ALA concentration range indicated SA-induced enhancement of renal ALAD over the entire range at both pH optima. Using 14C-labelled ALA, we have confirmed these observations made on the basis of a colorimetric assay for PBG, the enzyme product. We conclude that renal ALAD may be a different molecular species from the liver enzyme. Further studies may clarify the significance of these observations to renal heme synthesis.

Animals↗

PubMed1988

Effects of topical capsaicin on normal skin and affected dermatomes in herpes zoster.

Hyperalgesia and allodynia, lasting for months or even years, occurs in the form of post-herpetic neuralgia in approximately 70% of adults previously infected with the varicella herpes zoster virus. The present study aimed at testing the analgesic desensitising actions and reversibility of repeated application of topical capsaicin on disordered polymodal nociceptors and peptidergic sensory fibres mediating warm and pain sensation. Cutaneous nociceptor desensitisation was measured using the Glasgow automated thermal threshold test (Medelec TTT). For normal subjects (n = 69) the mean forearm warm threshold was 0.15 +/- 0.07 degrees C and the cold threshold was 0.14 +/- 0.10 degrees C. A variable degree of partial desensitisation of herpes-affected skin was found in 15 patients with post-herpetic neuralgia before capsaicin treatment where the mean threshold elevation for warm detection was 1.19 degrees C and 0.7 degrees C for cold detection, compared with the corresponding normal skin. In preliminary studies of 15 patients with post-herpetic neuralgia, good pain relief averaging 30% or 77% occurred in the affected dermatome(s) after 3 to 4 weeks of 0.01% or 0.05% capsaicin cream respectively, applied 3-4 times daily. The warm thresholds, after chronic capsaicin treatment, increased between 0.1 and 7.60 degrees C, the average elevation being 3.69 degrees C. By contrast cold thresholds after capsaicin altered inconsistently and by only an average of 0.08 degrees C. The results suggest that elevation of the warm threshold may indicate the desensitisation achieved by capsaicin treatment of skin polymodal nociceptors. Cold detection, being dependent upon A-delta cold fibre function, is unaffected by capsaicin treatment. There was a poor correlation between pain relief and elevation of warm detection in response to capsaicin treatment. Generally, it was found that those patients with less initial desensitisation to warm detection as a consequence of post-herpetic neuralgia experienced better pain relief after capsaicin was applied. The method used permits determination of the minimum effective desensitising dose of capsaicin, enables patient compliance and progress to be monitored and should allow the prediction of patients likely to achieve the best response to treatment.

Administration, Topical↗

PubMed1971

The detection of gratings in narrow-band visual noise.

1. The detectability of sinusoidal gratings comprised of either one or many cycles was measured in veiling luminances the spatial frequencies of which were either narrow- or broad-band.2. In narrow-band noise, the single-cycle grating was detected with approximately 0.6 log units less contrast than the many-cycle grating. On the other hand when both broad-band and narrow-band noise were present, there was no measurable difference in the detectability of the two types of grating.3. The results are interpreted as supporting the hypothesis of Campbell & Robson (1968) that spatially varying luminance patterns are processed by mechanisms selectively sensitive to limited ranges of spatial frequencies.

Differential Threshold↗

PubMedDate not supplied

Assessment of computer learning needs and priorities of registered nurses practicing in hospitals.

The purpose of this study was to identify computer learning needs of practicing nurses at the bedside. Knowles' adult learning theory clearly implies that learners have a role in identifying their learning needs. Expert opinion is the second source of needs identification and complements learner input. This principle served to underpin the conceptual framework of this study. A Delphi technique was used to solicit expert opinions from nurse informaticians about the computer learning needs of practicing nurses. A 75 knowledge/skill item questionnaire was developed from the expert consensus of the Delphi and distributed to 150 registered nurses considered to be computer novices. Novices' responses were compared to the experts' responses to identify content essential for nurses to be able to use computers in their practice. Further, sequence for content delivery was postulated through the comparison of expert and novice opinion relative to the essential/nonessential nature of the content.

Clinical Competence↗

PubMedDate not supplied

Impact of clinical information systems on nursing practice. Nurses' perspectives.

This article adds to the literature on the impact of computerized clinical information systems by asking nurses important questions about their nursing practices. A research tool was developed from collaborative work with clinicians who have used computers in their daily practice for more than two decades. A statewide study then was conducted on how nurses believed computer technology impacted their practice. This study also examined the different views that computer users and nonusers held. Questions were posed relating to resource consumption, nursing work practices, and professional and patient outcomes. It was found that nurses, whether computer naive or knowledgeable, clearly do not expect the technology to have negative impact on practice. The two groups differed mostly in the strength of their beliefs. One startling outcome, that slow computer response time delayed care, was identified within the computer-user group and direct action was taken as a result.

Attitude to Computers↗