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Biomedical subjects

P Lawrence

Publications and source records attributed to P Lawrence.

At least 19 recordsLinked to original sources
PubMed2005

Milk fat synthesis is unaffected by abomasal infusion of the conjugated diene 18:3 isomers cis-6,trans-10, cis-12 and cis-6,trans-8,cis-12.

It has been previously established that trans-10,cis-12 CLA is a potent inhibitor of milk fat synthesis. Although the mechanism of this action is not completely understood, it has been speculated that eicosanoid-like metabolites of this isomer formed by the activity of tissue desaturases may be responsible for its activity. The objective of this study was to investigate the effects of an enrichment containing an 18:3 conjugated diene, produced in the metabolism of trans-10,cis-12 CLA, on milk fat synthesis. Three rumen-fistulated Holstein cows (210+/-8 d in milk) were randomly assigned in a 3 x 3 Latin square experiment. Treatments were (i) control, (ii) trans-10,cis-12 CLA supplement (2.1 g/d; positive control), (iii) enrichment providing two conjugated diene 18:3 isomers (2.6 g/d of cis-6,trans-10,cis-12 and 4.0 g/d of cis-6,trans-8,cis-12) and trans-10,cis-12 CLA (2.1 g/d). Treatments were abomasally infused for 5 d at 4-h intervals, and there was a 7-d interval between periods. Milk yield, dry matter intake, and milk protein yield were unaffected by treatments. In contrast, the trans-10,cis-12 CLA supplement reduced milk fat yield by 27%, whereas the supplement enriched with conjugated diene 18:3 isomers (treatment iii) had no effect on milk fat yield beyond that attributable to its trans-10,cis-12 CLA content. The transfer efficiency of trans-10,cis-12 CLA into milk fat was 25 and 24% for treatments ii and iii, respectively. At the same time, the abomasally infused conjugated diene 18:3 isomers were transferred to milk fat with an efficiency of 33 and 41% for cis-6,trans-10,cis-12 and cis-6,trans-8,cis-12 18:3, respectively. Overall, short-term abomasal infusion of the conjugated diene 18:3 isomers had no effect on milk fat synthesis, thereby offering no support for an involvement of metabolites of trans-10,cis-12 CLA in the regulation of milk fat synthesis.

Abomasum↗
PubMed2005

Adaptive management and its role in managing Great Barrier Reef water quality.

Adaptive management is the pathway to effective conservation, use and management of Australia's coastal catchments and waterways. While the concepts of adaptive management are not new, applications involving both assessment and management responses are indeed limited at the national and regional scales. This paper outlines the components of a systematic framework for linking scientific knowledge, existing tools, planning approaches and participatory processes to achieve healthy regional partnerships between community, industry, government agencies and science providers to overcome institutional barriers and uncoordinated monitoring. The framework developed by the Coastal CRC (www.coastal.crc.org.au/amf/amf/_index.htm) is hierarchical in the way it displays information to allow associated frameworks to be integrated, and represents a construct in which processes, information, decision tools and outcomes are brought together in a structured and transparent way for adaptive catchment and coastal management. This paper proposes how an adaptive management approach could be used to benefit the implementation of the Reef Water Quality Protection Plan (RWQPP).

Animals↗
PubMed2002

Phenotype/genotype associations for yield and salt tolerance in a barley mapping population segregating for two dwarfing genes.

Barley traits related to salt tolerance are mapped in a population segregating for a dwarfing gene associated with salt tolerance. Twelve quantitative trait loci (QTLs) were detected for seven seedling traits in doubled haploids from the spring barley cross Derkado x B83-12/21/5 when given saline treatment in hydroponics. The location of QTLs for seedling growth stage (leaf appearance rate), stem weight prior to elongation, and tiller number are reported for the first time. In addition, four QTLs were found for the mature plant traits grain nitrogen and plot yield. In total, seven QTLs are co-located with the dwarfing genes sdw1, on chromosome 3H, and ari-e.GP, on chromosome 5H, including seedling leaf response (SGa) to gibberellic acid (GA(3)). QTLs controlling the growth of leaves (GS2) on chromosomes 2H and 3H and emergence of tillers (TN2) and grain yield were independent of the dwarfing genes. Field trials were grown in eastern Scotland and England to estimate yield and grain composition. A genetic map was used to compare the positions of QTLs for seedling traits with the location of QTLs for the mature plant traits. The results are discussed in relation to the study of barley physiology and the location of genes for dwarf habit and responses to GA.

Adaptation, Physiological↗
PubMed2001

Double bag or Y-set versus standard transfer systems for continuous ambulatory peritoneal dialysis in end-stage renal disease.

BACKGROUND: Peritonitis is the most frequent serious complication of continuous ambulatory peritoneal dialysis (CAPD). It has a major influence on the number of patients switching from CAPD to haemodialysis and has probably restricted the wider acceptance and uptake of CAPD as an alternative mode of dialysis. OBJECTIVES: This systematic review sought to determine if modifications of the transfer set (Y-set or double bag systems) used in CAPD exchanges are associated with a reduction in peritonitis and an improvement in other relevant outcomes. SEARCH STRATEGY: A broad search strategy was employed which attempted to identify all RCTs or quasi-RCTs relevant to the management of end-stage renal disease (ESRD). Five electronic databases were searched (Medline 1966-1999, EMBASE 1984-1999, CINAHL 1982-1996, BIOSIS 1985-1996 and the Cochrane Library), authors of included studies and relevant biomedical companies were contacted, reference lists of identified RCTs and relevant narrative reviews were screened and Kidney International 1980-1997 was hand searched. SELECTION CRITERIA: Randomised or quasi-randomised controlled trials comparing double bag, Y-set and standard CAPD exchange systems in patients with ESRD. DATA COLLECTION AND ANALYSIS: Data were abstracted by a single investigator onto a standard form and subsequently entered into Review Manager 4.0.4. Odds Ratio (OR) for dichotomous data and a (Weighted) Mean Difference (WMD) for continuous data were calculated with 95% confidence intervals (95% CI). MAIN RESULTS: Twelve eligible trials with a total of 991 randomised patients were identified. In trials comparing either the Y-set or double bag systems with the standard systems significantly fewer patients (OR 0.33, 95% CI 0.24 to 0.46) experienced peritonitis and the number of patient-months on CAPD per episode of peritonitis were consistently greater. When the double bag systems were compared with the Y-set systems significantly fewer patients experienced peritonitis (OR 0.44, 95% CI 0.27 to 0.71) and the numbers of patient-months on CAPD/ episode of peritonitis were also greater. REVIEWER'S CONCLUSIONS: Double bag systems should be the preferred exchange systems in CAPD.

Humans↗
PubMed2001

Culturally sensitive care of the Muslim patient.

The number of Muslims in the United States is growing. This article outlines a few of the major beliefs in Islam. Religious and philosophical factors that affect health care are discussed, and practical suggestions are made for nursing actions that lead to culture care preservation, culture care accommodation, and culture care restructuring. Major topics covered include the need for cleanliness, preparation for prayer, modesty, family structure, fasting and diet, and care of the dying.

Delivery of Health Care↗
PubMed2000

Evidence-based medicine and health economics: a case study of end stage renal disease.

This paper explores the potential for use of an economic evaluation framework alongside systematic reviews. Clinical issues in dialysis therapy for end stage renal disease are used as case studies. The effectiveness data required were obtained from a systematic review of randomized controlled trials. Resource use and cost data were obtained from three sources; the identified randomized controlled trials, a separate review of observational studies and primary data collection. The results of the case studies show that, although simple economic evaluations were possible, issues arose, such as how transferable results are between settings and how appropriate it is to focus on the average patient. The interface between economic evaluation and systematic reviews needs to be further developed in order to ensure that the best available evidence can be used to inform future policy and research.

Chi-Square Distribution↗
PubMed2000

Chronic effects of streptozotocin-induced diabetes on the ultrastructure of rat ventricular and papillary muscle.

Contractile dysfunctions have been demonstrated in different experimental models of diabetes which have similar characteristics to many of the abnormalities found in the clinical setting. Administration of streptozotocin (STZ) to young adult rats induces beta-cell necrosis of the pancreas which gives rise to hypoinsulinaemia and hyperglycaemia, features which are also seen in untreated type 1 clinical diabetes. We have investigated the chronic effects of STZ-induced diabetes on contraction in rat ventricular myocytes and ultrastructure of cardiac muscle. Diabetes was induced in male Wistar rats (230-270 g) with a single injection of STZ (60 mg kg(-1)). At 2 and 10 months after STZ treatment, the amplitude of contraction was larger in diabetic compared to control myocytes. Time to peak contraction was significantly longer at 2 months but appeared to normalise at 10 months after STZ treatment. In contrast, time to half relaxation of contraction was not significantly different after 2 months but was significantly reduced at 10 months after STZ treatment compared to control. Transmission electron microscope examination of cardiac muscle showed that the ultrastructure of cardiac muscle, especially structures associated with contraction, were not greatly altered after STZ treatment. Sarcomere lengths were not significantly different in papillary or ventricular muscle at 4 or 8 months after STZ treatment compared to control. Our data provide evidence that morphological defects in contractile myofilaments and associated structures cannot explain contractile dysfunctions seen in ventricular myocytes from STZ-treated animals.

Animals↗
PubMed2000

Evidence-based medicine in nephrology: identifying and critically appraising the literature.

BACKGROUND: Uncertainties about best management of end-stage renal disease (ESRD) are reflected in wide variations in practice. Systematic reviews aim to reduce uncertainty by strengthening the evidence base for clinical practice, allowing estimation of the benefits and risks of particular interventions, whilst minimizing the potential for bias. This paper describes the methods and conduct of six systematic reviews of aspects of the management of ESRD, and the yield in terms of trials found. METHODS: Our methodology was based on that recommended by the Cochrane Collaboration (an international initiative set up to perform and disseminate systematic reviews of health care). It involved a systematic search of electronic databases and bibliographic reference lists, together with handsearching of Kidney International for studies relevant to the management of ESRD, followed by a systematic assessment of study quality. RESULTS: Around 12,000 abstracts were assessed which had been identified from electronic sources. Of these, 2085 (18%) were deemed to be reports of possible randomized or quasi-randomized controlled trials relevant to the management of ESRD. Three hundred and forty were relevant to the six specific reviews, and after assessment of the full manuscripts, 39 studies were finally included in our reviews. Reports of a further nine trials, which were identified from other sources, were also included. The broad search adopted allowed the parallel development of a register of trials of all aspects of the management of ESRD. CONCLUSIONS: This study has demonstrated that the methodology of systematic reviews, as promoted by the Cochrane Renal Group, is feasible but has significant resource implications. The development of a register of randomized controlled trials (RCTs) related to the management of ESRD will facilitate this form of research in the future.

Databases as Topic↗
PubMed2000

Generation of medial and lateral dorsal body domains by the pannier gene of Drosophila.

The pannier (pnr) gene encodes a GATA transcription factor and acts in several developmental processes in Drosophila, including embryonic dorsal closure, specification of cardiac cells and bristle determination. We show that pnr is expressed in the mediodorsal parts of thoracic and abdominal segments of embryos, larvae and adult flies. Its activity confers cells with specific adhesion properties that make them immiscible with non-expressing cells. Thus there are two genetic domains in the dorsal region of each segment: a medial (MED) region where pnr is expressed and a lateral (LAT) region where it is not. The homeobox gene iroquois (iro) is expressed in the LAT region. These regions are not formed by separate polyclones of cells, but are defined topographically. We show that ectopic pnr in the wing induces MED thoracic development, indicating that pnr specifies the identity of the MED regions. Correspondingly, when pnr is removed from clones of cells in the MED domain, they sort out and apparently adopt the LAT fate. We propose that (1) the subdivision into MED and LAT regions is a general feature of the Drosophila body plan and (2) pnr is the principal gene responsible for this subdivision. We argue that pnr acts like a classical selector gene but differs in that its expression is not propagated through cell divisions.

Abdomen↗
PubMed1999

Primary antiphospholipid syndrome with moyamoya-like vascular changes.

We describe a young girl with antiphospholipid syndrome (APS) and moyamoya-like cerebrovascular changes which reversed after anticoagulation. Although there was a risk of hemorrhage from collateral vessels, we speculate that this treatment may have prevented progression of the vascular abnormalities, while resolution of the thrombus resulted in improved cerebrovascular circulation.

Antibodies, Anticardiolipin↗
PubMed1998

Phase I trial of a 96 h paclitaxel infusion with filgrastim support in refractory solid tumor patients.

A phase I study of a 96 h paclitaxel infusion with filgrastim support was performed to determine the toxicity, maximum-tolerated dose (MTD) and pharmacokinetics in patients with refractory solid tumors. In this phase I trial, the initial paclitaxel dose was 140 mg/m2/96 h followed by filgrastim (5 microg/kg/day s.c.) beginning 24 h after the paclitaxel and continued until granulocyte recovery. Cycles were repeated every 21 days. Patients with refractory solid tumors were eligible; however, only one previous chemotherapy regimen was allowed. The dose of paclitaxel was escalated by 20 mg/m2/96 h in subsequent cohorts until dose-limiting toxicity (DLT) occurred. Pharmacokinetic analysis was performed by quantitating paclitaxel concentrations at baseline, 24, 48, 72 and 96 h after the start of the paclitaxel infusion. Twenty-one patients were entered into this trial of which 19 were evaluable. A total of 52 treatment cycles were administered. DLT was seen in two of four patients at 200 mg/m2/96 h, and consisted of diarrhea, mucositis and granulocytopenic infection. The MTD of the 96 h paclitaxel infusion was 180 mg/m2 with filgrastim support. Mucosal and granulocyte toxicity were correlated with steady-state paclitaxel concentrations (Css) greater than 0.100 micromol/l. In the presence of liver function test 1.5 times or lower than normal, metastatic liver disease did not alter paclitaxel Css. Objective responses were observed in non-small cell lung cancer, small cell lung cancer and melanoma. The recommended phase II dose of paclitaxel infused over 96 h with filgrastim support is 180 mg/m2. Paclitaxel Css correlate with mucosal and granulocyte toxicity. In the presence of normal enzymatic function, metastatic liver disease does not affect paclitaxel clearance.

Adult↗
PubMed1997

Bilateral iliac artery aneurysms and pancake kidney: a case report.

Renal fusion and ectopia are anomalies of the proximal urinary tract that present a special challenge to vascular surgeons. We present a rare case of bilateral iliac artery aneurysms in a 70-year-old man with a fused pancake kidney. The patient underwent preoperative evaluation with a computed tomographic scan and angiographic examination, followed by bilateral iliac artery reconstruction. Pancake kidney is a rare renal anomaly, and its association with aortoiliac disease has been referred to only one other time in the literature. Successful management is dependent on preoperative recognition of the renal anomaly, aortographic examination to delineate renal blood supply, and careful operative preservation of renal vasculature.

Aged↗
PubMed1997

Comparative morphology of the alimentary tract and its glandular derivatives of captive bustards.

This study describes the gross anatomy of the alimentary tract of Houbara Bustards (Chlamydotis undulata macqueenii), Kori Bustards (Ardeotis kori), Rufous-crested Bustards (Eupodotis ruficrista) and White-bellied Bustards (Eupodotis senegalensis) maintained in captivity by the National Avian Research Center in the United Arab Emirates. The morphology of the alimentary tract and the proportions of each region were similar in all 4 species. The length of the oesophagus, combined proventriculus and ventriculus, small intestine, and large intestine formed 24.2-28.4%, 7.3-9.7%, 40.5-55.1% and 9.1-14.7% of the total alimentary tract length respectively. Neither crop nor oesophageal enlargement was observed in the birds examined in this study, although male Kori Bustards possessed a saccus oralis in the oropharyngeal cavity. Oesophagi, proventriculi, ventriculi, caeca and large intestine were well developed in all species. The small intestine was shorter than that of other avian herbivores and granivores when compared on a bodyweight basis. The well differentiated stomachs and well developed caeca of the bustards examined in this study are characteristic of omnivores. Analysis of the mean lengths of the alimentary tract components and weight of the liver and pancreas showed sexual dimorphism in cases where male and female data were available for direct comparison.

Animals↗
PubMed1993

The effects of recombinant human growth hormone and intradialytic parenteral nutrition in malnourished hemodialysis patients.

Malnutrition in hemodialysis patients is associated with increased morbidity and mortality. The use of intradialytic parenteral nutrition (IDPN) to improve nutritional parameters has been shown to be of limited benefit in most studies. We studied the use of recombinant human growth hormone (rHuGH) in potentiating the effects of IDPN in seven hemodialysis patients dialyzed with a Kt/V of 1.03 +/- 0.11 (mean +/- SEM), but with evidence of malnutrition: albumin, 3.2 +/- 0.18 g/dL; transferrin, 215 +/- 30 mg/dL; insulin-like growth factor-1 (IGF-1), 115 +/- 19 ng/mL, protein catabolic rate (PCR), 0.70 +/- 0.05 g/kg/d; and weight, 12.3% +/- 4.0% below ideal body weight. During 6 weeks of IDPN, resulting in an additional 18 +/- 4 kcal and 0.69 +/- 0.03 g of protein/kg body weight per dialysis session, albumin concentration increased to 3.5 +/- 0.14 g/dL (compared with baseline, P = NS), transferrin increased to 279 +/- 36 mg/dL (P < 0.002), IGF-1 increased to 152 +/- 32 ng/mL (P = NS), and PCR increased to 0.81 +/- 0.04 g/kg/d (P = NS). During the next 6 weeks, IDPN administration was continued and rHuGH, at a dose of 5 mg subcutaneously during each dialysis, was added to the regimen. This resulted in an increase in albumin concentration to 3.8 +/- 0.08 g/dL (P < or = 0.04 compared with end of IDPN phase), an increase in transferrin to 298 +/- 41 mg/dL (P = NS compared with end of IDPN phase), and an increase in IGF-1 to 212 +/- 45 ng/mL (P = 0.05 compared with end of IDPN phase).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1993

A human factors evaluation of two different machine control systems for log loaders.

The implement movement in today's mobile, heavy machinery does not correspond in a one-to-one proportion with hand control movement. This lack of correspondence places high perceptual and psychomotor demands on the operator. The objective of this study was to evaluate the human factors of two different machine control systems on a log loader in a controlled field setting. The traditional joint control system was compared with a co-ordinated control system. The two machines were tested on ten novice and six experienced operators. Operator performance was based on the time required to complete a task sequence, as well as reaction time. The results show that the novice operators performed significantly better in co-ordinated mode than they did in joint mode, whereas the experienced operators performed better in joint mode than they did in co-ordinated mode. Results indicate, however, that it would not take long for experienced operators to transfer their skills from joint control to co-ordinated control.

Forestry↗