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Biomedical subjects

G Bishop

Publications and source records attributed to G Bishop.

At least 19 recordsLinked to original sources

Dwarfism and cytochrome P450-mediated C-6 oxidation of plant steroid hormones.

BRs (brassinosteroids) are plant steroid hormones that are essential for normal plant development. The dramatic dwarfism exhibited by mutants in the CYP (cytochrome P450) enzymes involved in BR biosynthesis indicates a role for these hormones in plant growth and development. Since the mid-1990s, collaborative research has been geared towards developing a better understanding of the CYP85 class of CYPs involved in BR biosynthesis in both Arabidopsis and tomato. Some of the most recent observations include the fact that certain CYP85 CYPs catalyse the synthesis of the most bioactive BR, BL (brassinolide). Current evidence suggests that evolution of this function may have occurred independently in different dicotyledonous species. Interestingly, BL accumulates in tomato fruits, highlighting a key role for this hormone in fruit development. At the same time as developing a better understanding of the enzymatic function of these CYPs, we have also carried out experiments towards characterizing where and when these genes are expressed and mechanisms of their regulation. As expected for a hormone involved in growth and development, biosynthetic gene promoter activity is associated with young rapidly growing cells and with fruit development.

Arabidopsis↗

The Medical Emergency Team: 12 month analysis of reasons for activation, immediate outcome and not-for-resuscitation orders.

OBJECTIVE: To describe the reasons for, and immediate outcome following Medical Emergency Team (MET) activation. METHODS: Retrospective analysis of MET calls in 1998. RESULTS: There were 713 MET calls to 559 in-patients. Of the 559 patients 252 (45%) were admitted to ICU and 49 (6.9%) died during the MET response. The three commonest criteria for calling the MET were a fall in GCS>2 (n=155); a systolic blood pressure<90 mmHg (n=142) and a respiratory rate>35 (n=109). Cardiac arrests accounted for 61 calls and had an immediate mortality of 59%. The most common MET criterion associated with admission to ICU was a respiratory rate >35. Of patients who received MET calls based only on the 'worried' criterion 16% were admitted to ICU. The MET felt that a not-for-resuscitation order would have been appropriate in 130 cases (23%). NFR orders were documented during 27 of the MET calls. CONCLUSIONS: The MET system provides objective and subjective criteria by which medical and nursing staff can identify patients who become acutely unwell. A high proportion of these patients will require admission to Intensive Care. The MET system also provides the opportunity to identify patients for whom an NFR order should be considered.

Adolescent↗

Routine blood test ordering for patients in intensive care.

Current practice is for a number of blood tests to be routinely performed on intensive care unit (ICU) patients. A survey of routine blood testing amongst ICUs in Australia and New Zealand was conducted. Ninety-six ICUs completed the survey form. Blood electrolytes, liver function, arterial blood gases and full blood count were the most frequently ordered tests. Routine blood testing was not practised in 12.6% of ICUs. The presence or absence of written guidelines did not influence the frequency of the most commonly performed routine blood tests. Clinical and operational factors specific to each ICU appear to impact on such blood tests and guidelines for their use.

Australia↗

Intra-abdominal hypertension is an independent cause of postoperative renal impairment.

HYPOTHESIS: Intra-abdominal hypertension exerts an effect on renal function independent of other confounding variables. DESIGN: A prospective study of all patients admitted to an intensive care unit following abdominal surgery was undertaken between September 1, 1994, and July 31, 1997, in a single university hospital. MAIN OUTCOME MEASURES: Intra-abdominal pressure (IAP) was measured every 8 hours (normal IAP, 0-17 mm Hg); 18 mm Hg or higher was considered increased. Forward stepwise logistic regression determined whether intra-abdominal hypertension is an independent cause of renal impairment. RESULTS: A total of 263 patients (174 after emergency surgery), whose mean +/- SD age was 61.0 +/- 18.7 years and Acute Physiology and Chronic Health Evaluation II score was 14.6 +/- 7.7, were studied. Intra-abdominal pressure was increased in 107 (40.7%) of the 263 patients. Renal impairment occurred in 35 (32.7%) of the 107 patients with intra-abdominal hypertension and in 22 (14.1%) of the 156 with a normal IAP (odds ratio, 1.62-5.42). Using the Wald maximizing model, renal impairment was independently associated with 4 antecedent factors: hypotension (P= .09), sepsis (P = .006), age older than 60 years (P = .03), and increased IAP (P = .004). CONCLUSIONS: To our knowledge, for the first time in a large clinical study, IAP has been shown to be an independent cause of renal impairment, and it ranks in importance after hypotension, sepsis, and age older than 60 years. Surgeons need to be aware of the importance of intra-abdominal hypertension in patients postoperatively.

Abdomen↗

Assessing the appropriateness of coronary revascularization: the University of Maryland Revascularization Appropriateness Score (RAS) and its comparison to RAND expert panel ratings and American College of Cardiology/American Heart Association guidelines with regard to assigned appropriateness rating and ability to predict outcome.

BACKGROUND: Significant regional variation in procedural frequencies has led to the development of the RAND and American College of Cardiology/American Heart Association (ACC/AHA) guidelines; however, they may be difficult to apply in clinical practice. The University of Maryland Revascularization Appropriateness Score (RAS) was created to address the need for a simplified point scoring system. HYPOTHESIS: The study was undertaken to compare revascularization appropriateness ratings yielded by the RAND Expert Panel Ratings, ACC/AHA guidelines, and the University of Maryland RAS. METHODS: We applied these three revascularization appropriateness scoring systems to 153 catheterization laboratory patients with a variety of cardiac diagnoses and treatments. For each patient, appropriateness scores assigned by each of the three systems were compared with each other and with the actual treatment delivered. Concordance of care with appropriateness score was then correlated with outcome. RESULTS: There were significant differences among all three scoring systems in their ratings and in the concordance of treatment with appropriateness rating. When treatment provided was concordant with RAND ratings, there was a lower occurrence of subsequent coronary artery bypass grafting (CABG), the composite end point of either CABG or percutaneous transluminal coronary angioplasty (PTCA), and the composite end point of death, myocardial infarction (MI), or revascularization. When treatment was concordant with the ACC/AHA guidelines, there was lower occurrence of all-cause mortality, PTCA, the composite end point of either CABG or PTCA, and the composite end point of death, MI, or revascularization. When treatment provided was concordant with the RAS, there was lower occurrence of cardiac death, all-cause death, CABG, the composite end point of either CABG or PTCA, and the composite end point of death, MI, or revascularization. CONCLUSIONS: The RAS is a simple scoring system to assess revascularization appropriateness. When the RAND, ACC/AHA, and RAS systems are compared in a catheterization laboratory population, they rate the same patient differently and vary in their correlation of appropriateness rating with outcome.

Adult↗

The Medical Emergency Team.

The concept of a Medical Emergency Team was developed in order to rapidly identify and manage seriously ill patients at risk of cardiopulmonary arrest and other high-risk conditions. The aim of this study was to describe the utilization and outcome of Medical Emergency Team interventions over a one-year period at a teaching hospital in South Western Sydney. Data was collected prospectively using a standardized form. Cardiopulmonary resuscitation occurred in 148/522 (28%) calls. Alerting the team using the specific condition criteria occurred in 253/522 (48%) calls and on physiological/pathological abnormality criteria in 121/522 (23%) calls. Survival rate to hospital discharge following cardiopulmonary arrest was low (29%), compared with other medical emergencies (76%).

APACHE↗

An analysis of the critical problem of trauma center reimbursement.

There is a widespread perception that many trauma centers are poorly reimbursed, and many hospitals that once cared for trauma victims no longer do so, primarily for financial reasons. The problem is blamed on both uninsured and underinsured patients, but data supporting this perception are lacking. To determine the validity of these perceptions and to better understand the nature of trauma center reimbursement, a survey was conducted. A questionnaire on the volume of trauma seen annually and the reimbursement experience for trauma center (TC) and hospital (HO) patient populations was mailed to representative but nonrandomly chosen trauma centers. Seventy-one surveys were mailed and 25 were returned (35%). There were 15 Level I and 10 Level II centers; 16 were urban, seven were suburban, and two were rural. Eighteen centers (72%) reported significant underfunding of the TC in contrast to the HO, and 11 indicated that they would not be able to continue their current level of TC services with present reimbursement. For Medicare patients, HO cost recovery rates averaged 93%, but recovery rates were only 64% for TCs. For Medicaid beneficiaries, the HO cost recovery rate averaged 85%, but it was only 49% for TCs. Thirty-one percent of TC patients had no insurance coverage at all, in contrast to only 9% of HO patients. An aggregate loss equal to 19.9% of total costs was reported by respondents. This survey, while not representative of trauma centers as a whole throughout the United States, does suggest that there is a basis for the perception of underfunding of trauma care and indicates that such underfunding results from the combination of adverse selection and disproportionate share. We also describe a new method for assessing and comparing trauma center reimbursement.

Data Collection↗

Crescentic IgA nephropathy as a manifestation of human immune deficiency virus infection.

A 37-year-old Caucasian male homosexual presented with hematuria and rapidly progressive acute renal failure. He was found to have proteinuria and microscopic hematuria as well as RBC casts. Investigations revealed polyclonal gammopathy with five times normal serum IgA levels as well as elevated serum IgG. Renal biopsy showed evidence of crescentic IgA nephropathy with ultrastructural changes of tubuloreticular inclusions described in HIV nephropathy. He was found to be positive for human immunodeficiency viral antibodies. Renal function improved during follow-up after two doses of 1 g each of methylprednisone. In our opinion, this is the first case of HIV-related crescentic IgA nephropathy. HIV testing should be performed more frequently in patients presenting with acute glomerular diseases.

AIDS-Associated Nephropathy↗

A differential scanning calorimeter for ice nucleation distribution studies--application to bacterial nucleators.

A differential scanning calorimeter has been developed for the automatic detection and measurement of dropwise freezing within a sample of 100-200 water drops. A typical drop size of 1 microliter is employed. The sample is distributed on flat, square (4-cm) thermoelectric sensors and the temperature is scanned downward by conductive cooling to a liquid nitrogen bath. The rate of cooling, typically 1 degree C/min, is set by the choice of a heat conduction rod between the calorimeter and the liquid nitrogen bath. The voltages from the thermopiles along with a system temperature-measuring thermocouple are continuously monitored by digital voltmeters and recorded every half-second in a computer memory. A freezing event in a drop is detected by a characteristic voltage signal whose integral with time is proportional to the size of the drop and its heat of fusion. The half-life of a freezing event signal is 10 s for a 1-microliter drop. The integrated signal produced from multiple freezing events is shown to provide a direct measure of the number of drops frozen at a given temperature. A distribution curve and its smoothed derivative can be constructed directly from these measurements. The instrument, which is termed an "ice nucleometer," is illustrated in determining the ice nucleation distribution in a population of Escherichia coli harboring cloned ice nucleation genes.

Calorimetry, Differential Scanning↗

Generalized binding phenomena in an allosteric macromolecule.

A general macromolecular partition function is developed in terms of chemical ligand activity, temperature and pressure for systems described by an array of species which are characterized by their state of allosteric conformation and ligand stoichiometry. The effects of chemical ligand binding, enthalpy change, and volume change are treated in a parallel manner. From a broad viewpoint all of these effects can be regarded as specific cases of generalized binding phenomena. This approach provides a general method for analyzing calorimetric and ligand binding experiments. Several applications are given: (1) Thermal scanning data for tRNAphe (P.L. Privalov and V.V. Filimonov, J. Mol. Biol. 122 (1978) 447) are shown to fit a general model with six conformational states. By application of linkage theory it is shown that sodium chloride is expelled as the molecule denatures. (2) The results of calorimetric titrations on the arabinose binding protein (H. Fukada, J.M. Sturtevant and F.A. Quiocho, J. Mol. Biol. 258 (1983) 13193) are shown to fit a simple two-state allosteric model. (3) A thermal binding curve is simulated for an unusual respiratory protein, trout I hemoglobin (B.G. Barisas and S.J. Gill, Biophys. Chem. 9 (1979) 235), in order to illustrate both the similarities and differences between enthalpy and chemical ligand binding processes.

Allosteric Regulation↗

Child sex abuse treatment: some barriers to program operation.

A treatment program for sexually abusing families is described, which illustrates the complexities in the families, in the treatment required to assist them, and in the interrelations of agencies with whom they come into contact. The program used a multi-therapist, multi-modality treatment model in conjunction with expert consultants in medicine, psychology, art therapy, law, criminology, and research. The article discusses the formidable barriers to creating a treatment program that stem from the necessity of establishing linkages with other agencies and systems in the society. These barriers include the difficulty other service providers may have in recognizing the problem; the trouble doctors, lawyers, and policemen have in interviewing the young victims; the problems in the criminal justice system with obtaining justice for the victim by arresting and prosecuting the offender while protecting his rights; and the conflict of the schools caught between their responsibility as mandated reporters of abuse and the legal rights of the parent-offender. Questions are raised which may assist others embarked on developing similar programs.

Adolescent↗